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The History Of British Submarine Command Systems

by Commander David Parry

'Periscope Eye', the sine qua non for a submarine commanding officer

There has always been a symbiotic relationship between the submarine commanding officer, the submarine's sensors and whatever command aids were available. The harder and more often the three worked together the better was the attack solution provided.

In the early days, the relationship was purely between the CO and the periscope. Using only the periscope, a CO had to be capable of holding the surface picture mentally and directing his submarine into what he perceived as the optimum firing position to hit a target. With just a few simple tables to help him, an attack was conducted solely by eye and hence the moniker 'periscope eye' evolved and having a good 'periscope eye' became the sine qua non for a submarine CO.

E Class Attack Aid
E Class Attack Aid

An E Class Attack Aid

The simple tables used by submarine COs until the advent of the Is-Was survive in this example from an E Class submarine. The tables were:

  • Range from masthead height and periscope angle
  • Deflection angles for 29 and 41 knot torpedoes
  • Time, Speed, Distance

Periscope eye is what the submarine command course, be it the Periscope Course, the Commanding Officers Qualifying Course or the Submarine Command Course1 hoped or hopes to expose, develop and exploit. But, as there are so many aspects to 'periscope eye', they make it almost indefinable. Captain George Simpson, in his autobiography, Periscope all View, reflects on his time on Perisher in 1928 , "This sense of relative position in the Captain's mind's eye is what the success and the safety of the submarine chiefly depend upon". 2 Simpson again, talking about one of his commanding officers when he was Captain 10th Flotilla, in Malta during WW2, Lieutenant Edward A Woodward, says, "He had a particularly good eye for periscope attack". 3 At that time the periscope still dominated although there had been many improvements in asdics, and radar was about to make an appearance. The submarine CO also had by now, as we shall see, a few rudimentary instruments to help him. But, even after the war when John Coote refers to the capability of having 3-D vision through a periscope and being able to size up a given situation in full perspective, reliance on the periscope was still very much the case.4

Frigate seen through a persicope
Frigate seen through a persicope

A Frigate Seen Through A Periscope

The frigate looks like she will pass clear of the submarine but the CO has to determine whether she will pass sufficiently clear without him having to go deep for safety. All part of the 'periscope eye' capability.

A few generations later, Admiral Sandy Woodward reflected on the same issue when referring to holding a mental picture of the surface scene, "imagine sticking your head out of a manhole in Piccadilly Circus, taking one quick swivelling look around, ducking back down into the sewer and then trying to remember all that you have seen. The idea is to generate sufficiently accurate recall and timing to avoid a double-decker bus running over your head next time you pop up through the manhole". 5 Woodward was talking at the time of a well proven fire control system supported by a well understood and drilled command system albeit one that was an eclectic collection of nomographic plots.

In his paper 'Perisher: The Making of a Submarine Commander', written at the time of the Perisher centenary in 2001, Commodore Martin McPherson exposes but struggles with the periscope eye debate and adds a further dimension: "not get[ing] lost in the box". 6 Although he comes to an indistinct conclusion, he does prove that the ethos of the 'periscope eye' has endured from its earliest days, when eye and periscope were principal, to the computer-based command systems of the nuclear submarine.7

These, then, are some of the aspects of 'periscope eye': visual acuity through a periscope; the ability to visualise the all-round surface picture; the mental agility to solve the attack trigonometry; and the determination (often courage) to drive-home the attack.

The later United States Navy version was more practical and often hung around the neck on a lanyard

For the greater part of the past 100 years the submarine CO has been assisted by tools and instruments developed, in the main, by the imagination of submarine officers. Those attack aids have proliferated, matured and morphed over the years to form what is now known as a command system. This is the history of their evolution.

The 'Is-Was' - the first ubiquitous command aid

In the early years of submarine development, from the Submarine Service's conception in 1901 to WW1, the energies, intellects and attentions of submariners were focused principally on the development of the submarine itself. That is not to say, there were some important innovations that started with Captain Reginald Bacon's invention of the periscope8 and then the fitting of Fessenden gear in 19139, the forerunner of modern sonars, and the first radio that was fitted in the submarine Lieutenant Commander Martin Eric Nasmith in 1912.10

The Is-Was
Diagrammatic presentation of a later Is-Was that was mounted on a Sperry repeater
Diagrammatic presentation of a later Is-Was that was mounted on a Sperry repeater
The later United States Navy version was more practical and often hung around the neck on a lanyard
The later United States Navy version was more practical and often hung around the neck on a lanyard

At the same time, however, the Admiralty was pouring energy into the resolution of the surface ship gunnery fire control problem. The years of the British-German naval rivalry and expansion were filled with controversy and contention as to how best to direct naval gunfire. The principal rivalry was between the civilian inventor Arthur Pollen and the naval officer Frederic Dreyer, a contention and rivalry that survives, through the telescope of history, to today.11 Part of this gunnery story was created by a junior naval officer with a notable name, Lieutenant John Saumerez Dumaresq, and between 1902 and 1904 Dumaresq invented a manual mechanical instrument to determine the target's relative motion vectors. It was further developed, became electrical, and served throughout both world wars.12 The Submarine Service looked at using later models of the Dumaresq for finding target speed in 1925 but it was not favourably received. The principal reason was that the Dumaresq needed updating in the later stages of an attack, at the very time when the CO is trying to limit his periscope exposure.13

But one enterprising submariner was clearly familiar with the Dumaresq. This was Lieutenant Commander Martin Eric Nasmith,14 a man who was to become one of the most famous submariners. He joined the submarine service in 1904 and by July 1905, as a Lieutenant of just two months seniority and aged 22, he was appointed in command of the submarine D4.15 Nasmith was a prolific inventor.16 While there is no suggestion that he plagiarised the Dumaresq, when he later invented the Nasmith Director - an instrument to determine the optimum course to steer for an attack - its azimuth ring, bearing pointer and enemy bar clearly had reflections of the Dumaresq.17 The Nasmith Director was not, however, widely adopted. But his derivation from the Nasmith Director, the Is-Was, became a standard. The Is-Was provided the Deflection Angle, (DA), or aim-off. It was first used successfully in an attack by Lieutenant Claud Barry in the submarine D4 in 1918 when he sank the German U-boat UB72.18

The name Is-Was reflects "the key problem in computing the DA. Because the submarine and target both moved, computing the DA for where the target 'Is' right now only identified where the target 'Was' a moment ago. Because the target moved, it 'Is' somewhere else in the next moment of time, and because of this the DA had changed". 19 In other words, the Is-Was could not maintain a continuous solution.

The Is-Was was used extensively by both the Royal Navy Submarine Service and many other submarine services worldwide including, notably the United States Navy even when they had the far more sophisticated Torpedo Data Computer (TDC) as this excerpt, albeit fiction but well researched, from 'Run Silent Run Deep', and the now classic Clark Gable-Burt Lancaster 1959 film of the same name illustrates:

"Jim spoke again. "What course do I come to for a straight bow shot?"

Keith didn't answer immediately as he studied the figures on the face of the Is- Was. In a moment he said, "One-three-four," holding out the Is-Was to Jim as he did so."20

In 1929, following trials of the Spencer and Ionides Directors21 which were modifications to the Is-Was for 90° angling, it was intended to modify the Is-Was. That modification, however, was initially put on hold with the advent of a far more sophisticated innovation, the Submarine Torpedo Director (STD).22 But as the STD programme itself was delayed the Is-Was was eventually further improved, finally being connected to a Sperry gyroscope repeater so that it could be automatically updated. Shortly before the start of WW2, however, the Is-Was began to be finally replaced by the STD, or 'Fruit Machine' as it became known. (The Americans, had an earlier, parallel programme: the Torpedo Data Computer or TDC).23

The 1920s, a decade of invention

With the end of the war in November 1918 it seems that the submarine community had both the time and the intellectual capacity to reflect on how best to improve their capability. They produced an impressive plethora of initiatives in their search for a better attack solution and although many, if not most, failed, were rejected or proved too costly, it was not for want of effort. It is doubtful there has ever been a similar period of invention in the history of the Submarine Service. In particular, the 1920s was the time for proponents of the specially adapted submarine slide rule although there were many other inventions as well.

1920: Nasmith-Lockhart Slide Rule.24

As creative as ever, among the earliest inventors of this period reappears Nasmith. However, this time he teamed with another officer. His first post-war creation was known as the Nasmith-Lockhart Slide Rule.25 Nasmith was at this time a Captain in command of HMS Lucia and the submarine flotilla fighting the Bolsheviks in the Baltic. Anthony Bevis Lockhart DSC was a Lieutenant Commander in the flotilla. The purpose of the slide rule they invented was to find inclination or angle on the bow by taking vertical and horizontal angles of the target.

This was apposite, for back in 1903 Barr and Stroud had been approached by the Holland Torpedo Boat Company to design a rangefinder for submarine periscopes. The company was a natural choice for it was making most of the Navy's rangefinders and had a close working relationship with the Admiralty. However, there was no apparent enthusiasm from the Admiralty so any ideas were not taken to a design stage.26 Then, in December 1915 Commodore Sydney Hall, the Inspecting Captain Submarines,27 met Barr and Stroud's Chief Scientific Assistant, James French, to resurrect the earlier rangefinder work. The company

took a standard rangefinder, turned it through 90°, and mounted it vertically in the periscope. A mock-up was made and shown to Hall in July 1916 and shortly afterwards the company received orders for 13 FY1 range-finding periscopes.28 The first FY1 periscope, using a stadimeter was fitted in the minelayer submarine M3 within a year of being ordered in 1919.29 At the time Nasmith and Lockhart were in the Baltic so they may have been unaware.

Shortly afterwards, in the early 1920s, a periscope was developed that had the added advantage of being able to range in the horizontal plane as well as the vertical plane so if the target's length was known, the angle on the bow could be determined from the virtual length and thereby the target's course.30 This horizontal capability would have fulfilled Nasmith and Lockhart's ambitions but for reasons unknown it disappeared from later periscopes.

The stadimeter principle on the left was favoured by the British in the Barr & Stroud periscopes . An image of the target was superimposed on the real image using a known height. The Americans and Germans favoured the reticule on the right where a known height (or length) is assessed against the marks in the Kollmorgen and Zeiss periscopes respectively.

The Commander (S) at HMS Vulcan viewed the proposition circumspectly. He commented "There is a marked tendency in modern Submarine Officers to prefer the use of slide rules generally to tables". He further considered that "the instrument would not be of much help in the attack until after considerable practice"31 and suggested that the top half of the slide rule which gave range and distance off track be combined with a time, speed and distance slide rule.32 Nothing, however, appears to have happened to that suggestion for in 1927 Lieutenant Commander E B Clark, who was on Perisher at the time, proposed combining what appears to be the same two slide rules.33

1920: Garnons-Williams Instrument34

Lieutenant Commander Gerald Aylmer Garnons-Williams was clearly a superior officer. No lesser people than two future Flag Officer Submarines, Robert Raikes and Max Horton, were to say of him when he was First Lieutenant, in the as a qualified CO,35 that he had, "Ability exceptional. A most capable and reliable officer has much character and initiative… specially recommended for early promotion." 36

In 1920, when CO of the L21, Garnons-Williams invented a speed finding instrument which can better be described as a rate of change instrument used in conjunction with a modified Mark VIII Dumaresq. The genius of this invention was that it was an early, automatic time bearing plot. A band of paper was fed by clockwork in a vertical direction over a marking drum. The paper moved at a constant rate and provided a timescale. The horizontal axis provided a bearing scale and bearings were cut from the periscope with a mark being made on the paper. This allowed the rate of change of bearing to be obtained from the slope of the line. This was done using a revolving grid mounted in front of the paper with graduations around the ring on which it was supported. A downside of the instrument was found during trials by the Periscope Course (Perisher) officers who determined that when a target was sighted with an angle on the bow less than 30°, by the time the submarine had moved to increase the angle on the bow, and presumably increase the bearing rate sufficiently to be read on the instrument, the range was reduced to a point where there was a danger of the periscope being sighted.

In 1923, 13 instruments were ordered from Elliott Bros Ltd for trials at sea in a variety of submarines.37 However both Captains (S) Second and Fifth Submarine Flotillas decided against its continued use. Nonetheless, when the new CO of HMS Oberon in 1926, Lieutenant Commander Guy d'Oyly-Hughes learned that a Garnons-Williams instrument was to be fitted in his submarine he felt so emotional about it that he wrote directly to Rear Admiral (S) bypassing the normal chain of command asking that it be removed claiming that it did not produce anything like an exact answer, that most commanding officers did not use it and that it took up valuable space. We can only presume he won his case.

Although there is a suspicion that Garnons-Williams did not use his innovation himself he was not giving up.38 Ten years later, in 1933, when he was now Commander (S) Fifth Submarine Flotilla based on HMS Alecto he attempted to resurrect what he now called his Chemical Automatic Recorder. Unfortunately the 13 instruments that have been made in 1924 had all been returned to the dockyards and none could be found.

1921: Cooper Slide Rule39

Lieutenant Patrick Francis Cooper was CO of the H52 when he came up with the idea to simplify the attack process with a new slide rule that had five scales and multiple functions:

  • Range from masthead height
  • Distance off track from range and inclination
  • Speed, time and distance
  • Speed of enemy when closing on a steady bearing
  • Speed of enemy from range and change of bearing
  • Inclination of enemy from a vertical and horizontal angle

The introduction of such a complicated slide rule was, perhaps, something of a cultural change for the more established submarine officers. Captain Cecil Ponsonby Talbot, Captain (S), Second Submarine Flotilla, and later Rear Admiral (S), wrote:

"It is probably very useful to Officers who are adepts (sic) and have confidence in slide rules, but there is a large number of submarine officers (including myself) who are very suspicious of them, and consider they are likely to lead one astray in moments of stress".

Needless to say, Cooper's Slide Rule went nowhere although one had been produced for trial but whether such a trial took place is not known.

1922: Standley-Hutchinson Instrument40

Lieutenant Hugh de Lane Standley was First Lieutenant of the submarine H50 and Lieutenant Commander Alexander Scope Hutchinson was CO of the H44 when they combined to produce an automatic plotting instrument about which we know nothing else other than it was found to possess little advantage over hand plotting and was not proceeded with.

1922: Varley-Nasmith Periscope41

The Barr and Stroud periscope work mentioned earlier under the Nasmith-Lockhart initiative was ironical for Nasmith had subsequently teamed with another submarine officer, Lieutenant Commander Cromwell Hanford Varley although by now Nasmith was the Flag Captain in HMS Iron Duke so he had probably been working on the project while Captain (S) in the Lucia, his previous command. The idea of the Varley-Nasmith periscope was to have an additional eyepiece in the periscope through which could be viewed a model of a ship. The intent was then to compare the known inclination of the model against that of the target. The system was actually fitted in the submarine X1 for a trial but it was considered that the results did not justify the expense.

1922: Range Finding "Fixed Base" Periscope42

Lieutenant Commander Guy d'Oyly-Hughes, who was born an American,43 was a highly decorated submariner who had showed the extent of his courage, imagination and capability in the Sea of Marmara under Nasmith and later in command of the E35.44 He was to later die in contentious circumstances as Captain of HMS Glorious in June 1940.45 At the time he came up with his idea of the Fixed Base Periscope he was already an experienced submarine CO having commanded four submarines.46

D’Oyly-Hughes’ sketch of his Range Finding “Fixed Base” Periscope
D’Oyly-Hughes’ sketch of his Range Finding “Fixed Base” Periscope

D'Oyly-Hughes intent was to solve the range problem and improve the accuracy and thereby success probability of long-range firings outside 1500 yards. He considered that a horizontal rangefinder would be superior to the vertical one already developed because there will be no light differential. With a more accurate range and the use of a simple plotting device that he also suggested, in his view the 'art' of submarine attacking would be turned into a 'science'.

He was, however, only too well aware of just how likely a 4'6" long instrument was likely to be visible from a target ship. His rather impractical solution for this was to keep it sideways on until it was needed to take a range, similarly when raising and lowering. And he advocated some trials with a wooden mock-up mast secured to the fin of a submarine.

It is not known whether d'Oyly-Hughes was aware of, and therefore plagiarising, the 9 feet periscope range finder that had been installed in the submarine X1 just a year earlier47 or his idea was really original. No matter what, it is not really surprising that, however enterprising his ideas may have been, they were not taken up. The periscope vertical rangefinder continued being fitted throughout the fleet; the horizontal version went nowhere.

1923: Norfolk-Standley48

This time Standley teamed with Lieutenant Robert Galliano Norfolk to produce a 90° angle director. While the idea is noted in the records unfortunately there are no details about the instrument available.

1924: Vulcan Director49

HMS Vulcan was the depot ship of the Sixth Submarine Flotilla based at Portland. As no specific officers are named in association with this initiative we can presume it was a joint effort to create a 90° angle director to do, presumably, a similar job to the Norfolk-Standley. Five Vulcan Directors were purchased for trial a year later in 1925. In 1927 approval was obtained for an improved design to be worked out with a view to supplying all submarines. However, this idea was dropped in favour of the Spencer Director.

A 1924: Combined Slide Rule50

Lieutenant Commander EB Clark had probably just completed or was actually on Perisher when he developed his combined slide rule to supersede the one then in use by rationalising the number of slides. For example, on Clark's slide rule range and distance off track could be read simultaneously whereas it took two slides on the existing slide rule. Clark was credited with considerable zeal, energy and ingenuity but opinions were divided as to its further use. Captain (S) at Dolphin considered that it "possesses no marked advantages over the instrument now supplied". 51 Rear Admiral Henry Grace, Rear Admiral (S), decided that because the First and Second Flotillas were about to receive the Submarine Plotting Board Mark 1 he was not proceeding with the adoption of Clark's Slide Rule.52

Combined Slide Rule
Combined Slide Rule

Clark's innovation was to combine the two slide rules which was used extensively.

1924: Speed Finding Slide Rule53

Lieutenant Thomas Mark Taylor was CO of the submarine H47 when he produced his speed finding slide rule. It was trialled at sea in the submarines L23, L52 and M3 and was judged against the Garnons-Williams instrument. In favour of Taylor's slide rule were the ability to use minimum periscope in the final part of an attack and it was a lot cheaper. However, yaw of the submarine, which was compensated for in the Garnons-Williams, introduced errors and there were problems if the target 'zigged. It also suffered when angle on the bow was low. The conclusions were that while the instrument was of some value with the broad target, it was consistently in error and it was judged that equally good results could be obtained by the ordinary methods of plotting. An example of such plotting is shown. It's called the 'Millward method'54 and was based on three bearings and a single range from which is extrapolated the best course and speed to fit the bearings from the range. Future submarine officers would recognise it instantly as the Local Operations Plot (LOP)

1925: The use of the Dumaresq55

Dumaresq Mark VIII
Dumaresq Mark VIII

While the Dumaresq, in various developments, was used extensively in surface ships its application in submarines had been limited and not standardised.56 One of the first actions Rear Admiral Vernon Harry Stuart Haggard, the new Rear Admiral (S) took was to promulgate a suggestion by the Captain (S), Fifth Submarine Flotilla as to how to use a Dumaresq to find a target's speed. Trials were carried out by submarines at sea notably submarine L23 who identified three limitations concurred by his Captain (S) and Commander (S), Third Submarine Flotilla, namely, it was fiddly, could not be used by the CO himself and was reliant on an accurate range. The critical issue was that the accuracy of range decreased

the greater the range and at closer ranges the instrument demanded too much periscope exposure. While the instrument was not withdrawn it was left up to independent COs to use it at their discretion. Rather alarmingly, to modern sensitivities, the Captain (S), HMS Dolphin considered that "The most successful estimates of speed both in peace and war are generally those based on consideration of the circumstances, viz., the target ship, speed she can go, and the degree of hurry she is in etc." Clearly a man who believed in the 'periscope eye'.

1926: Murphy Bearing Plate57

It was Lieutenant John Murphy, who had been a Mate and therefore promoted from the lower deck, who came up with an idea of a night director although no details have survived but it was presumably fitted on the bridge of the submarine. It was trialled in the submarine Oberon, the captain of which was Lieutenant Commander D'Oyly-Hughes who must have reported it as unsuitable.

1928: Mackenzie Director58

Lieutenant Commander Colin Charles Lucas McKenzie had already been a submarine CO for nine years, and was rapidly approaching an out-of-zone for promotion status, when he suggested another type of night director that was to be mounted on a Sperry repeater. Like his career, he retired in 1933, it is unlikely that the Director was acted upon.

1928/1929: Spencer and Ionides Directors and Is-Was Mark II59

Commander Henry Spencer, a senior wartime-experienced submarine CO; was Commander (S) at the time of his Director development. He was attempting to modify the Is-Was to cope with 90° angle firing. One instrument was made for trial and was well reported on. Lieutenant Commander Hugo Meynell Bryan Ionides was either on Perisher or had just completed the course when he tried to modify the Is-Was in much the same way as had Spencer. (His surname was corrupted into the nickname 'Tinsides).60

The American 'Banjo'. An improved Is-Was, named after its shape. It was unwieldly in the confines of a submarine’s conning tower
The American 'Banjo'. An improved Is-Was, named after its shape. It was unwieldly in the confines of a submarine’s conning tower
Again one instrument was made and trials were conducted to compare it to the Spencer instrument. As a result of these trials it was decided to produce a new instrument to be known as the Is-Was Mark II. it would incorporate the best features of both the Spencer and Ionides Directors and the intention was to provide all submarines capable of 90° angle fire with the instrument.

The Americans had also improved on the Is-Was by producing a new handheld device that because of its appearance became known as the 'Banjo'. It had a top disc for relative bearings on which was set the target's angle on the bow and thereby course. Ships course was on a lower compass rose disc. An interchangeable baseplate for different torpedoes gave torpedo run in yards and gyro angle left or right from 0° to 180°. It was a cumbersome object, however, and not popular with submarine officers in the confines of an American submarine's conning tower.

The intention to produce the Is-Was Mark II was not proceeded with because the Submarine Torpedo Director (STD) was about to make its introduction and this was a new, important and almost revolutionary development.

1930: Modification to the Combined Slide Rule for 'O' Class Submarines61

First, however, Lieutenant Commander Philip Ruck-Keene62 had the privilege of making the recommendation for the last slide rule modification recorded during the decade - one that indicated that periscope rangefinders were now prevalent throughout the fleet. Ruck-Keene was the CO of the new submarine Oswald which he took out to the China Station and from which he was promoted. His suggestion was a modification of what was called the Hutchings Range Estimator. This was a slide rule graduated with the actual angle sub tendered at the periscope when used in low power (1.5 x magnification) which when read against the target height gave the range of the target. However, the periscope was also capable of ranging in

high-power (6 x magnification) in which case the rule was reading four times the actual angle. His modification was simple, he just wanted to re-graduate the scale and reword it to 'Rangefinder Angle'. No doubt this was done.

Plotting is introduced

The Plotting Board is conceived

One invention that was to have long lasting implications came from Lieutenant Commander Alistair Shand Cumming, an experienced submarine officer who had taken his Perisher in 1919.63 In 1925 he was on the staff course at Greenwich where an "experimental plotting instrument" with a pantograph for transferring bearing lines was being considered.64 This gave Cumming the idea of a similar instrument for use in submarines and he put forward the proposition for a circular plotting board.65

A contract to produce a plotting board to Cumming's design was placed with George Lee & Sons whose business was on The Hard in Portsmouth. The board is described thus:

The Plotter contains a revolving circular plotting board [25 ½ x 21 the half inches in diameter]66 the circumference being marked in degrees from 0° to 360°. This is mounted inside the body of the instrument, which contains a lubbers line. A protractor with a bearing arm is attached by means of a pantograph so that the bearing arm when set to 0° is always parallel to the lubbers line.

A table at the side enables the plotting officer to record the targets (sic) bearing, range, course, and the submarines' (sic) movements, below the above a time speed and distance run scale is provided. A small drawer is fitted containing a pair of dividers and a short scale. The latter is marked so that each small division represents the distance run in one minute at two knots, and each large division one minute at eight knots. (Scale 1-inch: 1000-yards.)67

The board was trialled in the submarines H32 and L56 and also by the then Instructional Officer (Teacher), Lieutenant Commander Gerald Edward Colpoys and his Perisher students in the attack teacher at Fort Blockhouse. (Whether he also trialled it at sea is not known). The trials were favourably commented upon, with a special commendation from Coploys who commented that all "officers should be required to be proficient in its use before passing out of the Training Class and Submarine Commanding Officers Course in the same way as examinations in the Battenburg are held for the qualification for the rank of lieutenant". 68

The idea clearly caught the imagination of Rear Admiral (S), and as a consequence, one of the last actions of Rear Admiral Haggard was to make a decision to provide a standardised Plotting Board for all L Class and later classes of submarine.69 The board was subsequently modified so that, among other things, the pantograph was removed and the protractor fitted in the box with the board all of which fitted in a drawer underneath the chart table.70

With the provision of the plotting board, in June 1927, Captain (S), First Submarine Flotilla, identifies the instruments that effectively make up the first command system. They were:

  • Iswas (sic)
  • Slide Rule [Combined Slide Rule]
  • [Cumming] Plotting Board
  • [Periscope] Rangefinder
  • Patent Log71

The Brewerton Plotting Table nearly makes it into submarines

Meanwhile, the surface fleet had been working on developing an automatic plotter for ships. The Brewerton Mark 1-A had been selected over the Sperry Villiers Odograph and in November 1928 Fleet Order 2989, Fleet Organisation, Exercises, Navigation etc. was issued pronouncing in detail: where the table was to be placed, the communications needed and the personnel to operate it in the five selected capital ships, and eight ships of the Mediterranean and Atlantic Fleets that were to get the tables for trial.72 The intent was that, following the trials, the tables will be provided to the wider fleet over the next two years. The staff of company that made the table, Booth & Brewerton, which seems to be lost to history, must certainly have been enthusiastic at the prospect of having to produce so many tables.

A single plot table was 5' x 4' (a double plot for flagship use was 9' x 4') consisting of a glass top with a pantograph arm for plotting and underneath an electrically driven position keeper fed by the gyro and log. It stood 2'6" high. This was a large piece of equipment to get through a submarine hatch.

While the surface ships to receive the plotters were given detailed instructions the Fleet Order identified that submarines were being dealt with separately. This was to cause some problems. Rear Admiral (S) was required to conduct a trial of the table but he had been misinformed. He was told that the table was 40" x 30" and the size could be varied to meet requirements. Thirty inches may just have gone down a submarine's hatch but when it arrived the table was found to be 46 x 39". Not only would the hatch be a problem, so would control room space so the only submarines they could possibly try it in were the X1 and K26. But by now the X1 was limited to 13 knots and this was not considered sufficient to test the table properly. Additionally, to fit a table in the K26 meant extensive modifications to tanks, ventilation, electrical equipment and not least the chart table which would lose chart stowage that would have to be moved to behind the Chief and Petty Officers' bunks. One can easily imagine how unpopular and impractical a solution that would have proved. As a consequence, the two submarines never did do any trials of the table.73 Nor, as Rear Admiral (S) made clear, was it going in an L Class submarine until its size was reduced to that of the plotting board, 26" x 22", and the height was reduced from its 2'6".

A Brewerton Plotting Table. The size was an encumbrance to submarine fitting.
A Brewerton Plotting Table. The size was an encumbrance to submarine fitting.

Clearly something was modified for a table was trialled in 1930 in the submarine L56. The commanding officer, Lieutenant Commander George Cunningham Paton Menzies, a most capable submarine CO who would later bring the China Flotilla to the peak of efficiency as Commander (S) just before WW2, found the table excellent for a strategic plot but otherwise no better than the Mark 1 Plotting Board with which he was probably more familiar. He did however, make a number of recommended modifications and these were adopted for a further trial in late 1930 in the attack teacher at Fort Blockhouse where once again Teacher and the Perisher students became the guinea pigs.

Teacher recognised some benefits of the Brewerton Plotter, notably that "it will give own ships position at any moment as accurately as the most efficient plotting board could obtain it. It relieves the plotting officer of any worry as to own ships position on the plot which is

the main difficulty with the present plotting board".(sic) Nonetheless, it was finally concluded that the Brewerton Plotter had no advantages over the plotting board. Rather, it had four disadvantages: its size ("great bulk"); reliance on an accurate log down to 1½ knots74; its use was deemed more complicated than the plotting board; and it called for additional mechanical upkeep. Some officers maintained a more conservative outlook on developments as one unknown staff officer indicates in an undated comment:

There are some CO's who are "Plot-minded" & who are prepared to sink their faith in such contrivances but I think (& hope) they [are] in the minority. The best & most successful S/M CO's are those who can carry a picture of the tactical situation in their heads & who can & do get hits without mechanical aids.75

Yet a further trial was conducted in the submarine Regulus in early 1933 and the commanding officer claimed that both on the surface and submerged it had worked "very satisfactorily" and "has been found to be of great value". 76 However, events had overtaken matters.

In 1924 the Admiralty Research Laboratory's (ARL) was developing a plotting table called the "Crawler", (the name appears to have been dropped in favour of the more prosaic ARL Table) which was a combined electrical and mechanical apparatus that resolved the course and speed of the ship into two components which by gearing were transmitted to a pencil travelling on a plotting table with a variable scale. The speed came from either a Forbes Log or alternatively from a clock on to which the estimated speed had to be set.77

The CO of the submarine L52 had been dispatched to Teddington to review this development which was the work of a Mr Young, a scientist at ARL, assisted by Messrs Champney and Lakey.78 He also had the opportunity to review the Sperry Villiers Odograph and the Brewerton Plotter. The conclusion he drew was that the ARL Table was better than the others because of the clock but that the size, cost and delicacy of the instruments did not justify their fitting in a submarine when the same job could be done by a Mooring (Plotting) Board. It was possibly because of this report that the ARL Table was not pursued and the Submarine Service was only spurred into action by the Fleet requirement to investigate the Brewerton Plotter

The ARL Table makes an appearance

he ARL Table was introduced into the Fleet in the mid-1920s and persevered into the 1980s. The picture shows the table's the centre point of the navigation centre in HMS Courageous. Surrounded by SatNav, SINS, Decca, gyro and log readouts the table can b e used for both navigation and the LOP although some boats had a second table for this purpose.
he ARL Table was introduced into the Fleet in the mid-1920s and persevered into the 1980s. The picture shows the table's the centre point of the navigation centre in HMS Courageous. Surrounded by SatNav, SINS, Decca, gyro and log readouts the table can b e used for both navigation and the LOP although some boats had a second table for this purpose.

In early 1931 Rear Admiral (S) was reminded of the ARL Table relative to the Brewerton Plotter.79 That is, it was being trialled in the tender to the anti submarine establishment at Portland, HMS Thruster, having already been at sea in the Nelson and Queen Elizabeth for two years. The trial reports must have been good for more ships were fitted with the tables80 and a decision was made in November 1933 that no more Brewerton tables were to be made and that the standard table for the future, made by Messrs Evershed & Vignoles,81 was to be the ARL Table.82 Submarines were to be fitted with one ARL automatic plotting table but they did not even appear in the list of priorities. Despite that, three tables were allocated for each of the three Thames Class submarines83 then building but before that happened, because of some doubt as to whether the tables would fit in the submarines, control room mock-ups were built. These were the first, and only WW2 submarines, to be fitted with an ARL Table until the A Class began to make an appearance at the end of the war followed soon afterwards by the T Class conversions. A note entitled 'An Introductory Lecture to Submarines' typed on flimsy foolscap sheets and dated 8th September 1958 survives as the first formal record of an ARL Table in a submarine. The note says that in the control room there is an: "A.R.L. plot to trace the directional movement (Track) of the submarine. Here a spot of light is projected from the plot upwards through a glass pane onto & plotting sheet spread over the panel. The spot is moved by the combined influence of the gyro compass, the log and a clock.84"

The ARL Table then became a permanent fixture of post-war and Cold War submarines and was fitted in all classes of submarine up to and including the Trafalgar Class.85 It was an integral part of the TCSS3-9 command systems when used for the LOP. By that time the ARL Table was very old technology indeed. This had been recognised and in the late 1970s a programme of development between ARL and Smiths Industries produced the Ship's Navigation and Plotting System (SNAPS).

The ARL Table in use as a LOP in an Attack Teacher
The ARL Table in use as a LOP in an Attack Teacher

Four of the principle components of the TCC9 command system can be seen here: the periscope, TCC, CEP in background and LOP in foreground. The TBP is out of view. In early days plastic strips marked with speeds to scale were used until the multi-pointed divider (below) was invented.

SNAPS replaces the ARL Table

In the surface fleet the ARL Table was being largely phased out of service as Action Information Organisation (AIO) automatic plotting systems took over. However, in the 1970s the importance of accurate navigation became increasingly important for the correlation of ships tracks during exercises and for use as a General Operations Plot. A 1976 Naval Staff Requirement started six years of development. The system that evolved had a central computer that took and processed inputs from all sources of navigation data, especially radio navigation aids. Importantly, for submarines, this included the Ships Inertial Navigation System (SINS). These inputs could be 'weighted' by the navigator to produce a best available navigational position.86 The table also performed as a Local Operations Plot (LOP) by performing target motion analysis on user input sonar and periscope information.87 It was, in effect, the automatic plotting table that had been called for many decades earlier.

A navigational console was designed for submarines to accommodate SNAPS, ships instruments, radio aids and a SINS remote terminal and was fitted into submarines in the late 1980s, the ARL Tables being replaced by the SNAPS table. This included the Trafalgar Class, Vanguard Class and even the Valiant Class. Astute was first fitted with a SNAPS table.88

From 2008, however, the Trafalgar Class and Vanguard Class of submarine had their SNAPS tables, in turn, replaced by RN WECDIS (Warship Electronic Chart Display and Information System). RN WECDIS consists of two linked consoles and a laptop for planning purposes accompanied by a 42 inch TV tilting screen. The hardware is supplied and maintained by Lockheed Martin but the software, which is to the International Maritime Organisation standards for EDCIS (Electronic Chart Display and Information System), is provided by OSI Maritime Systems. The Astute Class submarines also now have a WECDIS software system integrated into SMCS-NG.89

From plotting board to WECDIS was a long journey driven by technology, a submarine's capability and the tactical situation of the day. Although the developments demanded increasing knowledge and skills of the officers who used the equipment as an LOP during an attack, the underlying principles of that use, to determine course, speed and range of a target were unchanged.

The Submarine Torpedo Director is introduced

Commander Geoffrey Wyndham Wadham had had an inglorious career to date when he found himself working in the Directorate of Torpedoes and Mines (DTM) in 1927 for the second time in his career.90 His earlier appointment to DTM had been with the Fire Control Section in 1920-22. This was an important period during which the Admiralty Fire Control Tables (AFCT) were being developed under the leadership of the genius of Harold Isherwood supported by H F Landstad, from the Argo company,91 and a Service team of officers of which, presumably Wadham was one.92 Another participant was Hugh Clausen, the Chief Engineer in the Electrical Mechanical Department at the Admiralty's Ordnance Design Bureau. It is most probable that Wadham got to know Clausen during this period and picked- up the relationship when he returned to DTM in 1927.

But Wadham's appointments93 must have been 'square pegs in round holes', for Wadham was no intellect: he had gained no seniority as a Lieutenant and was a 2nd-class 'T' or torpedo specialist. However, he was clearly capable of identifying a problem and its potential resolution for while in his next appointment, in 1929, on the staff of the Rear Admiral Submarines, Martin Dunbar-Nasmith, he wrote a personal letter to Clausen in which Wadham identified the problem submariners had in determining the deflection angle or director angle as he called it (more commonly referred to as DA).94 The submariners, he said "So far they have had various directors which all have had little bars and pointers on them or if not have to be worked with a book of tables." He is clearly referring here to the earlier Nasmith Director and/or the Dumaresq, which both had bars and pointers of a kind and possibly the Is-Was although it is surprising he made no specific mention of the Is-Was which, by that time, had become the ubiquitous primary command aid. He identified the two differences between

firing a torpedo from a ship and a submarine as the latter fired only on relative bearings of 0°, 90° or 180°, whereas a ship fired from a much wider range of angles. Additionally, the submarine decided the track angle from which the DA for the target to reach the firing bearing was derived. This meant that the machine would have to take account of convergence invoked by the torpedo leaving the submarine and then turning to the torpedo track course. The resolution, he suggested to Clausen, was an instrument along the lines a of an existing torpedo sight.

It was from this approach by Wadham to Clausen that the Submarine Torpedo Director (STD), given the nickname 'the Fruit Machine' because of its similarity to vending machines of the day, was born.95

The STD was: "Designed to replace the present "Is-Was" instrument and the various slide rules used for subsidiary calculations". 96 It "is designed to cover, as far as is possible, all the requirements for firing torpedoes from submarines, either straight shots, or shots angled 90° right or left with proper allowance for "convergence". 97 But it failed to fulfil all the basic requirements to provide continuous:, up-to-date, target parameters of range, course and speed; torpedo gyro angle; and gyro angle transmission and setting.

Nor did its roll-out happen quickly. A demonstration model was not completed until 1934, (Clausen had had a nervous breakdown), when it was sent to Fort Blockhouse for trials in the attack teacher. Following a favourable report the director finally went into production in 1936 and began to be fitted to submarines in 1938 just in time for WW2.98 There were two versions which depended on the submarine's periscope to tube distance: the Mark 1 went into the smaller S Class and U Class submarines and the Mark 1x into other classes of submarine to be operated, according to Edward Young by the Third Hand.99.

The Submarine Torpedo Computer 'Fruit Machine'

On the left is the diagrammatic arrangement of the mechanism from TNA ADM 1/24278 Submarine Torpedo Director Marks I & I* Preliminary General Description

On the right is an STD in-situ in a control room

Three hundred STDs were made and another 80 went to the USA for transfer to the Russian Navy100 and they served throughout the war with great success but did not totally usurp the Is-Was which was often used to check a solution101. Quantification of the STD's efficacy came from the Awards Council hearing which concluded in Wadham's widow receiving an inventions award of £250 in 1945. There, the Director Naval Equipment is recorded as remarking, with reference to the STD:

It is in no way understating the case to say that very many tons of enemy shipping have been sunk by our submarines through using this instrument, and that a considerable percentage of this large total would probably not have been sunk without the use of it. The instrument has been an unqualified success". 102

Praise indeed, but there is no record of an award to Clausen, but then his job was to invent things.

The Slide Rule is not dead

The Torpedo Spreading Slide Rule or Greek Slide Rule
The Torpedo Spreading Slide Rule or Greek Slide Rule

Just to prove that the slide rule was not dead, many COs would still have an Is-Was to hand as a check on the STD and one of the long lasting innovations to come out of WW2 was the Torpedo Spreading Rule more commonly known as the Greek Slide Rule after its inventor, Lieutenant Commander Ypoploiarkhos E Tsoulkalas.103 This rule produced the firing interval and spread of various torpedo salvo combinations. Its use continued well after the end of WW2.

The American TBC: A possible replacement for the STD

Despite five U-boats being captured during WW2104 it was not until after the war that the British became fully aware of the German torpedo director, Torpedorichtungs-Weiseranlage (TRW). One ex-U-boat CO described it:

"The main torpedo fire-control table positioned near the periscope was unique and may well have given rise to justifiable astonishment after the war when our enemies had a look at it. It was not just a calculator of the normal kind with cog wheels, but a triangle-solving machine with various graphs and clones coupled up directly to the periscope. This made it possible to fire at five different targets in a convoy within the space of a few seconds without having to alter the original estimates of the convoy's course and speed. This device was largely responsible for our great successes in the Atlantic convoy battles". 105

Although unaware, the Royal Navy was well behind in terms of torpedo control. But in 1942, at the same time as the Germans were fitting their boats with the TRW, the Admiralty became aware of the American electro-mechanical, analogue Torpedo Data Computer Mark III(TDC).106 While having a fascia similar to the STD it did all that the STD failed to do. Consequently, much consideration was given to the purchase of an adaptation of the TDC for British submarines,107 an organisation under the Director Naval Ordnance (DNO) was set up and the intent was that the first TDC would be fitted in the Amphion.1082 There were many technical issues but with the acquisition of a few TDCs, these were by and large overcome. But there were some non-technical issues as well. The biggest of these was cost, the TDCs were unaffordable, supply was expected to terminate with the end of the war and they would probably be too late for the first A Class submarines.109

The unlikelihood of the American STD being available for British submarines was recognised by the Director of Naval Ordnance in August 1943.110 As a consequence, in September 1943 three schemes for the resolution of the fire control problem were tabled. Scheme A was for a simple modification to the STD for a gyro angle up to 30°. Scheme B was for a more elaborate modification for a gyro angle up to 55°. This scheme was not adopted. Scheme C was for a new design of STD.111 Admiral (Submarines) wanted the latter scheme to proceed with the highest priority but it was scaled back while consideration was still being given to the American TDC.112

The Torpedo Control System Submarines - TCSS2

The Scheme A modification to the STD was progressed to become the STD Mark IIx. Kipper Walker recalls it: "It had a position keeper which was meant to keep it up to date and required two operators!"113 The system became the Torpedo Control System Submarines 2 (TCSS2)114 and the disparagement implied in Kipper Walker's blog is echoed by Sam Fry's opinion of TCSS2*when he says "An adjunct had been fitted to make it [STD] the TCSS2*so that torpedoes could be angled rather than running straight using settings from the machine. The drill was horrendous and would have been so prone to error as to limit its use in war". 115

Meanwhile, at Bath, the Admiralty's endeavours to progress the Scheme C new design suffered a setback in 1952 when it produced a next generation prototype and sent it to the attack teacher at Rothesay. It lasted there just 24 hours, just long enough for Lieutenant Commander John Coote, the Commanding Officer Rothesay Attack Teacher, to realise that the new Torpedo Control Calculator's designers have not grasped the bearing rate issue. Back to Bath it went and it took some years for another computer to appear.116


The TDC could maintain a continuous solution wh ich the STD could not. However, the TDC was very large for the smaller British submarines and in the end it became unaffordable.

Made by Siemens it was in service in U - boats from 1942. It too was an electro - mechanical analogue computer that was part of an integrated fire control system.

That next computer, the Torpedo Control Calculator Mark 16 (TCC), came with the system to be known as TCS S/3 or TCSS3. The STD replacement, the TCC was, however, just one part of the complete TCSS albeit it is a central part. The full system had components that took feeds or provided data to every compartment in the submarine with the exception of the engine room thus making the submarine a complete weapon system. The Sound Room, Radar Office and Control Room (periscopes) all provided feeds into the STD/TCC. The Torpedo Stowage Compartment (Fore Ends) housed the amplifier cabinets and the Torpedo Tube Spaces both forward and aft received the settings for the torpedoes117. The principal components were:

  • The Submarine Torpedo Director (STD) which later became the Torpedo Control Calculator (TCC)
  • The Gyro Angle Re-transmission Unit (GARTU)
  • The Torpedo Order and Firing Instrument (TOFI)
  • The Torpedo Order Indicator (TOI)
  • The Tube Selection Unit (TSU)
  • The Amplifier Assembly


The TCSS3 was initially designed specifically for the T Class conversion submarines and the 21 inch Mark 8** torpedo. But the first installation was in HMS Andrew in September 1950 for sea-acceptance trials but the trials were a failure with three major defects the worst being the unacceptable errors in the determination of gyro angle.118 The resolution was to place the manufacturer of the TCCs with Barr and Stroud who were able to use their skills in precise gear cutting to resolve the problems.119 The result was a TCC accurate to within the required ±1°.120 When the system did get to sea the TCC was positioned at the foot of the conning tower ladder. This caused many problems from water coming down the tower and cascading over the machine. As a consequence, the T boasts had to either have the Elephant's Trunk121 rigged permanently on the surface or run opened-up for snorting on the surface.122


But the failure of the trials and the need to rectify the defects put the programme behind schedule causing interference with the next development, TCSS4. Although work started on TCSS4 in 1954123 it was intended for what was known as the 1953 submarine or the Boreas class although there is an indication it was also intended for the P Class submarines.124 The Boreas class sup>125 were to be submarines of about 1000-1200 tons, half the size of the Porpoise class and the TCSS4 was to include a number of operational features not fitted in the TCSS3. Two of these features may have been of the greatest importance. The first was a Bearings Only Analyser which was intended to use "the "Three bearing" method of deducing a relative course." - the Millward method. The second was that it would have a Target Position Keeper (TPK) and the first would provide a solution to the second.126 A complication was the adaptation of both TCSS3 and TCSS4 to accommodate the high test peroxide (HTP) powered, pre-patterned 'Fancy' torpedo - an attempt to replicate the German 'Inogolin', HTP powered torpedo by modifying a Mark 8 torpedo.127 However, the Boreas class was cancelled in 1956 following a rethink of submarine policy by the then Flag Officer Submarines, Rear Admiral Wilfred Woods. It was therefore decided that the Porpoise Class would have the TCSS3 with a Mark 12, 'Fancy’` capability. However, after the loss of the Sidon, (Lieutenant Commander Hugh Tyrell Verry), on 16 June 1955,128 the 'Fancy torpedo programme and hydrogen peroxide powered submarines were cancelled with the result that the Porpoise Class ended up with TCSS6.129 The downside was that the Bearings Only Analyser was delayed until 1971 and DCD.

TCSS5 and the TGCU1

With the cancellation of TCSS4 the focus of the Admiralty Gunnery Establishment, the responsible authority for the development of the systems, was the next variant TCSS5. Work had started in 1956 with the intention that the first production model would go into HMS Dreadnought in 1961. (She was finally fitted with TCSSS6).130 It was a complete rebuild of TCSS3 with some 1500 modifications being made so that all of Flag Officer (Submarines) 'user' proposals could be incorporated leaving just 20% of the original system. The TCC was re-designed by Barr and Stroud with a number of important modifications: repositioning and improving the hand-inputs; improved legibility of the dials; acceptance of transmissions from Asdic Type 187; and a re-designed angle-solver that improved accuracy among other things.131

An important capability was its interchangeability between torpedoes including wire guided weapons although the first British such weapon the Mark 23 'Grog' with its Torpedo Guidance Command System 1 (TGCU1) was only just starting trials at sea in HMS Scorcher at the same time as work began on TCSS5. The weapons the TCC was capable of interfacing with were the British torpedoes Mark 8 and Mark 20 'Bidder'. But it was also capable of interfacing with the American wartime Mark 16 mod 6, and the post-war Mark 27 mod 4 and Mark 28 mod 3 both electric passive acoustic homing weapons, a pre-set and search Mark 35 mod 2 and the new Mark 37 which was not yet wire guided.132


Anticipation of the introduction into service of the Mark 23 'Grog' torpedo brought with it, in 1965, the need for a new TCSS6 system that would be fitted in the remaining T Class, A Class and all P Class and O Class submarines. For the first time the fire control system had the ability to control a wire guided torpedo through the TGCU1, a rather ungainly piece of equipment with a poor display and poor ergonomics although Commander John Fieldhouse in the Dreadnought, trained his chef to operate TGCU1 – he was trying to make a point.133 But, the P Class and O Class could now fire weapons down to 300 feet.134

The TCC was upgraded to Mark 16 mod 3 incorporating eight important improvements including, most importantly, improved accuracy of the Angle Solver through a more exact method of setting it up by being able to take out the 'Fancy' capability thereby reducing range from 30,000 to 8000 yards, time of run to 11.25 minutes and reducing speed from 70 to 50 knots.135

TCSS9 and the TGCU2

The last analogue computer, TCC17, came with TCSS9, originally to replace theTCSS6 in the Oberon class. TCSS7 and TGCU1 had gone into the Valiant on build (replaced by TCSS9 and TGCU2 in 1972)136 but there is no record of a TCSS8. The big change that TCSS9 introduced was the TGCU2 and the ability to fire a Mark 24 Tigerfish torpedo. In fact, TCSS9 also had the capability to fire Mark 8 mod 2/3/4, Mark 20 (S), Mark 23 and the American Mark 37 mod 0, unguided, and Mark 37 mod 1 guided torpedoes.


Mk 23 & Mk 24 Torpedoes respectively

The ungainliness of control unit for the Mark 23 and the poor display panel for the Mk 24 guidance are evident.

But in 1967 the TGCU2 did not work and the original Project Leader had died of a heart attack taking much of the knowledge with him so TGCU2 needed a get-well programme and the Mark 24 Tigerfish trials were looming. The main issue was overheating. The lower drawer which had contained the cooling unit had been removed and replaced by the drum memory unit and its circuitry. To make matters worse, the hollow side skin of the unit was filled with cables which gave a Thermos flask affect and this affected both the germanium transistors and the analogue circuitry used to read and write to the drum memory. As a consequence, the Germanium transistors were replaced with silicon, analogue circuits were replaced with digital circuits and much of the system was redesigned.137

In the end, the TGCU2 made the test date only to find that the Mark 24 programme was not ready, the Tigerfish project had been working on the basis that TGCU2 would not be ready. The trials were a failure and it was another couple of years before they could be restarted. Nonetheless, TCSS9 was fitted in the Oberons and four of the Porpoise Class in a programme starting in September 1967 with HMS Oberon and running through to May 1974.138 It was also fitted to the Valiant Class and Resolution Class submarines.

In the end, the TCSS family spanned almost forty years. Even though some die-hard COs spurned its benefits139 it is not surprising that its use to determine the attack solution became a well-understood, well-drilled, well-executed and successful attack team effort, especially for the execution of a surface attack where the periscope and the captain's periscope eye were often the primary sensors. While the TCSS was central in this process it was complemented by an eclectic collection of mostly nomographic plots.

The search for a bearing-only solution

The early innovations

Shortly after the end of WW2 the policy for submarines, and thereby their tactical employment, changed to having a "primary aim… to be the destruction of enemy submarines". 140 This followed an important paper of 20 April 1949 by the Assistant Chief Naval Staff.141 The ramification of this doctrinal shift was that submarines, when attacking other submarines, could no longer rely on the periscope but would have to use sonar-only information. This, in turn, meant that the Target Motion Analysis (TMA) of an attack would have to rely on a bearing only analysis (BOA) and thus started a search for a resolution of this

problem. It became a priority of the Admiralty Gunnery Establishment as a series of papers pay testament;142 it also became the focus of thinking in the attack teachers.

Fortunately, some selective appointing was clearly in play at the Rothesay Attack Teacher for some of the Submarine Service's most cerebral officers found themselves on the staff and these intelligent and experienced submarine officers had both the facility and the time to give thought to the submarine vs submarine battle and its BOA analysis problems.

First was Lieutenant Commander Dicky Tibbatts, about whom John Coote, no slouch himself, talks in an admiring manner: "the brightest and most refreshing thinker at his level in the Submarine Service". 143 While at Rothesay in the late 1940s, Tibbatts had written a perspicacious paper entitled 'A Quick All-Round Look' identifying the short fallings in effective torpedo control systems. (At the time submariners were struggling with TCSS2). Clearly the Chief of Staff at the time was no match for Tibbatts' intellect, took offence and the paper was killed leaving the Royal Navy's Submarine Service lagging its peers for many decades.144

The first, and only, submarine ever credited with sinking another submarine when both were dived i.e. conducting a bearing-only 'blind attack', was HMS Venturer (Lieutenant James Launders) when she sank U-864 off Norway on 9 February 1945.145 Tibbatts took up the mantle of the BOA that this sinking illustrated by developing a choreography of pointing the target and then altering 90° to determine a unique solution for course and speed with a scaled ruler.146

Coote followed Tibbatts at Rothesay in 1950 and he took Tibbatts' innovations to the next step by developing the Time Bearing Plot (TBP): a vertical perspex sheet graduated in squares so that an appropriate scale could be used. It was mounted in the Control Room so that it could be viewed clearly with an operator sitting behind the sheet and, writing backwards, mark-a stoneup the bearings of the target using a chinagraph pencil. The TBP complemented the LOP, which had morphed from the Plotting Board to the ARL Table, as the two principal plots for the TCSS family's command system. (The Americans went one step further with their GUPPY submarines by replacing a wardroom bulkhead with a transparent plexiglass relative-bearing display, converting the wardroom table to the geographical plot - the equivalent of the LOP - removing an engine to accommodate pumps from the pump room and using the pump room to accommodate the TBP).147

Time Bearing Plot - The see-through Perspex sheetis marked in small for plotting squares bearing on the 'x' axis and time on the 'y' axis. An operator sat behind and wrote back-to-front.
Time Bearing Plot - The see-through Perspex sheetis marked in small for plotting squares bearing on the 'x' axis and time on the 'y' axis. An operator sat behind and wrote back-to-front.

Other notable submarine officers on the staff at Rothesay continued the search for the perfect BOA solution. Among them were: Lieutenant Commander Peter Herbert,148 who invented the 'Ettrick-method', a mathematical method of solving the bearings only problem so named because Herbert got his best ideas when gazing over the beautiful Ettrick Bay but its use fell by the wayside;149 Lieutenant Commanders Tony Whetstone150 and Mike Henry151 devised the Wet Hen plot (Wet for Whetstone and Hen for Henry) when they were 'riding' the USS Tullibee during a submarine v submarine exercise off New London in 1963. "It was another attempt to devise a way of firing using only the target's bearing rate to get a homing torpedo within range of the target. It was used by the USN in submarine v submarine exercises, but never succeeded in properly solving the problem and was not used by the Royal Navy"152. And Lieutenant Commander Sam Fry, later Teacher and Captain, considered the job of First Lieutenant of the Rothesay Attack Teacher as a plum job in 1956-1957 where the main thing he learnt was the BOA issue.153

The Contact Evaluation Plot

By the late-1960s TCSS6/9 were well proven, efficient fire control systems for the weapons of the time albeit the TGCU2 had ergonomic limitations (not to mention the torpedo) and the use of the TCC, chinagraph-TBP, pencil-multi-dividers-ARL Table-LOP, stopwatches and slide rules were a well-understood, well-drilled, well-executed and successful attack team effort, especially for the execution of a surface attack where the periscope and the captain's periscope eye were the primary sensors. But the tactical scene was BOA-focused where the sonar was the primary sensor and the attack team was having to become more of an analytical, consultative organisation. The captain was still, of course, central to the organisation because he was in command. But now, with him and around him, was the evolving command team concept.

Along with this evolution from periscope primacy to sonar dominance, and often its plethora of contacts, came a necessity to be able to understand both the surface, and underwater pictures on-the-watch rather than having to close up the attack team all the time which could, realistically, only manage one contact - the target - confidently. The resolution to this was the Contact Evaluation Plot (CEP) which was developed as an evolution from the earlier, rudimentary sonar Type 186 plot,154 The CEP comprised a role of graph paper displaying about 2ft² on which was plotted all contacts, both visual and sonar, together with own ship's movements and any other important information. The CEP was to become essential for a dived submarine and a generation of submarine officers who had lived with it throughout their careers found it difficult to dispense with when computerisation was later to arrive.

A Radar Plotter at the CEP
A Radar Plotter at the CEP
A Typical CEP Plot
A Typical CEP Plot
Own ship's course is the heavy straight lines. Further information would be added at the side. The CEP was an art.

More BOA initiatives

The Americans, not unsurprisingly, had also been very active in trying to find a BOA solution. In the 1960s and 1970s the USN had a very large and active tactical research and development organisation. Foremost in TMA, and especially BOA, was COMSUBDEVGRU TWO (CSDG-2) which became COMSUBDEVRON TWELVE (CSGS-12)155 but which is more commonly referred to as 'Devron 12'. Based in Groton, Connecticut the organisation had been formed in 1948 to develop the best practice experiences of the war.156 The Royal Navy had an exchange Lieutenant Commander liaison officer attached to Devron 12. Lieutenant Commander Robin King had been one of those liaison officers and in 1965, as a Commander, he set up the Royal Navy equivalent at Rothesay in the building that housed the attack teacher. This was called the Submarine Tactical Development Group (STDG) and an American submarine officer replicated the appointment of the British officer at Devron 12. STDG was to later morph into the Submarine Tactics and Weapons Group (STWG) when it was based in Faslane.

Undoubtedly, some of the developments by the Americans found their way across the Atlantic. One of the plots they used was the Lynch Plot and although some British submarines used it, for example Peter Samborne had one in HMS Sturdy in the early 1950s,157 it was not universally used in British submarines. The Lynch Plot had been invented as far back as early WW2 by the then Lieutenant FC Lynch USN (later Rear Admiral). His submarine, R-1, was to conduct some trial attacks against surface ships using an early sonar. He created the plot within two days and then perfected it, at sea, during the war.158 The variant used in British submarines was circular with own ship in the middle, not unlike the Plotting Board. Bearing lines were plotted and the bearing rate was marked along the bearing line using a special ruler. This produced a relative course. With an alteration of own ship's course, a second set of plots would intercept the first and the intersection between the first and second provided a range.

Another TMA method developed in the United States and used on occasion in British submarines was the Speiss Range. It applied to the TBP where a curve was either extended on, or back, to get a triangulation following an own ship's course alteration. The method was developed in 1953 by F N Speiss, not at a naval establishment but at the Scripps Oceanographic Institute in the USA. However, Speiss had been a wartime submariner.159

The most well-known, well-used BOA innovation to come out of the United States didn't come from Devron 12, it came from the USN Submarine School and a young lieutenant called John Ekelund in 1956. Looking at the problem afresh, Ekelund made some assumptions that enabled an equation to be created that gave range. But because his equation was based on assumptions of changing own submarine's speed across the target's bearing and the changes in the target's rates of bearing change, he needed empirical proof that it worked. So he co-opted the attack teacher over lunchtimes and ran through different scenarios. Convinced of his findings he had to bypass his immediate superiors to get his equation into the submarine domain where it was quickly adopted.160

The 1936 Range

Bearing Rate Protractor
Bearing Rate Protractor
1936 Range Slide Rule
1936 Range Slide Rule

It is too much of a coincidence that the Ekelund Range is not what became the 1936 Range in the RN and which the Americans, had it not been called the Ekelund Range, would have known as the 1934 Range.161 The 1936 Range was used extensively on the TBP and the CEP and its principles underpin some of the mathematics behind the later computer-based command systems. Ignoring the proof of the formula, the 1936 Range is expressed thus:

RANGE = 1936 (OSA 1~-OSA 2)/(Bdot 1~-Bdot 2)162 or
RANGE = 1936/1 x Change in Own Speed Across/Change in Bearing Rate or
RANGE (in Kyds) = 2 x Change in Own Speed Across/Change in Bearing Rate163

The bearing rate on the TBP was derived by smoothing out the curve by eye and then reading off the bearing rate at the tangent using a specially graduated protractor that would fit to the graduations and an arm would lie along the curve at the appropriate place. Many rules of thumb developed as the 1936 Range became familiar.

Frequency becomes key

Two events that were to have marked influences on the future development of submarine command systems then occurred. The first started shortly before the STDG was formed, when a Submarine School Weapons Officer, Peter Collinson, recognised that as the surface fleet was developing its computer-based AIO, the Submarine Service's arcane, manual nomographic plots, chinagraphs, pencils, paper and multi-pointed dividers while being well understood and used to maximum effect, were obsolescent certainly archaic. Collinson realised that being able to optimise the capabilities of the new nuclear submarines would

necessitate an influx of more scientifically thinking officers into the submarine cadre. This was appreciated within FOSM's staff and serendipitously, by way of the tennis court,164 a young Oxford mathematician, Lieutenant Guy Warner, an Instructor Officer, was not too unwillingly co-opted on to an Executive Officers' Training Course for submarine training. This was to prove a prescient and fortuitous move, for in 1967 Warner joined STDG and from hereon in Warner's participation in the resolution of the BOA problem and the development of future command systems was to prove a central factor in their success.

The appointment of Commander Sandy Woodward to command HMS Warspite marked the other milestone. When he had been Teacher, and was taking over from Sam Fry, Woodward realised that Fry knew the target was turning for the next training run because of the Doppler shift in the active sonar on the frigate escorts. Woodward developed this and "was able to apply some fairly ordinary mathematics, which, with some simple electronic equipment to do most of the work, produced all sorts of amazing information previously unavailable to us."165 At the time, Woodward introduced the rather unsuccessful idea of tuning forks in the control room to determine Doppler shift. But his reference to the 'amazing information' was something very different.

Commander John Hervey had previously been the CO of the destroyer Cavalier before he joined the Warspite without any special training166 to conduct a Special Navy Collection Programme (SNCP) mission167 during which he collided with a Soviet submarine. Woodward was to relieve Hervey, but before he took command he naturally wanted to avoid getting into a similar position. The key to it, he had surmised, would be the Doppler shift he had identified as Teacher. Not, this time, from a high-frequency active sonar, but from a low frequency noise radiated from the target. The sort of noise that had often been used to classify a contact. He went to see STDG which, under Commander Charles ET Baker, had been analysing the Warspite incident.

The trick, STDG concluded, was to reach a range-steady state that would reveal the base frequency to be analysed. The frequency above base then indicated that the range was closing and below base that the range was opening - valuable information, independent of bearing movement, when in the submarine trailing mode. Moreover, Warner, on the staff of STDG, devised a mathematical formula to work on an HP35 hand held calculator and a Range Evaluation Plot that plotted frequency rather than bearing evolved. although it had limitations when the frequency was unstable. A Low frequency analysis was now being used to glean tactical information. The frequency needed to be stable so that changes were due to relative movement only. Thus, it had to be emanating from high-grade machinery typical of nuclear submarines. To get useful numerical information it was necessary to measure frequency very accurately and only a few submarines initially had the sonar to do that. In 1969, the first Submarine Trailing Manual was written by STDG168 and a new generation of (circular) slide rules was born.169

But getting to the base frequency was not an easy thing to do.

Two Range Rate Circular Low Frequency Analysis Slide Rules

"Initially when narrowband tonals became the trailing norm the RN fell into the trap of deriving a so-called target base frequency eg 300HZ. Having calculated or estimated target range, adjustments were made to this range based upon the observed Doppler shift up or down plotted on a time frequency plot. What was not appreciated was that tonals being emitted from a Soviet submarine were often unstable and what could look like opening Doppler was in fact a closing situation". 170

It was realised that the observed frequency rate combined with bearing rate could be used to calculate target range. This was called a 1959 range and its own circular slide rule was developed. 171

A 1959 Range Sliderule
A 1959 Range Sliderule

Richard Sharpe got his opportunity to put the STDG manual into practice when he became CO of HMS Courageous in 1974 by which time Courageous had relieved the Warspite of SNCP duties. Sharpe used a colourful but apt analogy to explain the BOA problem:

"The most important and obscure of the submariner's black arts is the need to establish viable estimates of target course, speed and range, when provided only with passive sonar bearings. It is difficult enough when the noise source is constant, as in a cavitating surface ship propeller, but achieves a whole new plane of obfuscation when the contact is irregular. A simple analogy is that it is like being in a field with a herd of cows in pitch darkness. You can hear munching, the swish of tales, footfalls and the occasional seismic contribution to global warming, but only a fool would claim that he knows the exact PIM (position and intended movement) of any individual animal. Part genius or pure 'con job'.172

Later, when on the staff of FOSM, Sharpe went on to write a seminal document for submariners, 'The Concept of Operations' with its maxim "Not only prepared for war but operationally committed to today's confrontation". 173

The Computerised Command System

DCA174: the first fully computerised command system

As Sandy Woodward was preparing himself for his time in the Warspite in Faslane further south two developments under the Tactical Data Handling System (THDS) for submarines project were underway. The first was a joint private-venture by Vickers, Ferranti and Gresham Lion based on the Ferranti FM1600B computer. Hello yesterday the right the good life here quickly okay okay I give the Argo firm Marica call a yet to fight It was known as the Tactical Information Organisation System (TIOS) and it was being developed for the Oberon class. Although it was sold to the Israeli and Brazilian Navies it was not installed in British submarines.175

In 1971, the other initiative underway was at AUWE, the development authority for a system that was to become known as DCA. DCA was to accompany TCSS9 as the command system

replacing the manual plots and TCC. Ferranti were the lead contractor and DCA too, was based on the Ferranti FM1600B.176 The choice of the Ferranti FM 1600B, a military version of the Ferranti Argus computer, followed an earlier decision by the MoD to standardise computer development under the Christchurch Committee which rationalised the competing Elliott Bros., Marconi and Ferranti to just the Elliott 920 and Ferranti Argus ranges. The FM 1600 B processor had been selected for the surface ship CAAIS systems giving credibility for DCA.177

Warner joined the DCA project by way of an appointment to the very large Ferranti computer-based trainer project at HMS Dryad. He was, therefore, well-versed in the Ferranti surface ship AIO programmes and in computer technology in general.178

But he had joined too late to participate in the decision as to the principles behind DCA and he realised the software would have some limitations due to the least squares and exponential smoothing mathematical principles on which it was based. Also, operationally, although it could cope with many contacts it could still only cope with one target. The project had been made aware of the principles of Kalman filtering that had already been used by the Americans in navigational and guidance systems by RAE Farnborough179 but it was Warner who had the inspiration to adopt the principles to resolve the BOA problem. Although his ideas were too late to have an influence on the development of DCA, Warner wrote the necessary software for the use of Kalman and tried it out on the AUWE computers. It worked but it wasn't adopted.180

DCD: an interim measure

In the same year, 1971, HMS Courageous was nearing completion in Barrow so the SNCP programme was in urgent need of a BOA computer for close range use. Lieutenant Commander John Bench was the Naval Projects Officer and responsible for a major part of the design. He wanted to use the DCA BOA software to gain some sea experience in its operability, but this was vetoed for cost and resource reasons. A ready-made version was therefore sought and the Swedish Navy had one, but for political neutrality reasons they declined to provide it even though they had provided a similar version to the Norwegian Navy. AUWE and Ferranti therefore had to put together an interim piece of equipment known as DCD fitted with a 1600B computer and standard modules to reduce design and manufacture time. The design was completed within six weeks and the first module ready for installation within nine months when it was installed in the Courageous' control room between the LOP's ARL Table and the CEP.181 The DCD emulated the TBP but allowed an operator to generate his own solution using manual manipulation of range, course and speed to match the bearing rate being developed by the DCD. Sonar bearings were automatically input but the Human-Computer-Interface (HCI) used hand wheels to input the key parameters.182

Only two were produced183 and although technically they may have been a success, especially with the urgency with which they were designed and made, the operators in the Courageous were not so enamoured.184 Two issues were that, like the TBP, it could only handle one target and for unknown reasons it used to spew out paper tape "usually at the least convenient time, much to the irritation and frustration of the CO, the embarrassment of the maintainers and the covert amusement of the rest of the Control Room Team."185 One can imagine the effect of this in a tense tactical situation. The other limitations, however, were that it required an operator and so did nothing to relieve the manpower-dependency of the command system and, of course, if the bearing rate match was made it was not necessarily the correct solution (although a course alteration could help to create a unique solution).

The DCA programme progresses

While DCD was going to sea in 1971, progress on the development of DCA with its least squares algorithms - and following not far behind, its replacement DCB - continued. In addition to dormant software failings were the ergonomics of the HCI, for DCA was a scion of ADAWS. While internally the computer language used was updated from Coral 64 to Coral 66 and its core store increased from 32k to 64k the inherited HCI was to cause problems. Much effort had been put into developing a "conversational mode of interacting" HCI and many technology solutions have been looked at. Light pens were deemed to be the most flexible and proved popular in other systems.186 DCA inherited the light pen for its HCI. It had also inherited a hierarchical library-based input procedure neither familiar nor intuitive to the operators but to which they were burdened. This caused frustrations and operators tended to take their frustration out on the light pens, unsurprisingly breaking them.187

The two displays, with an operator each, usually ran time and bearing on one display and a plan picture on the other but with built in flexibility. In between the displays, was the Principle Coordinator Officer's console which displayed various basic ship's information and had a sonar Type 2001 active display repeater, although, as submarines rarely transmitted it was little used other than as an OOW chinagraph notebook. An issue with the DCA picture display was that the contact solutions were presented on a plan display rather like a radar display. This generated a perception that 'what was seen was the truth' when in fact, it could be anything but the truth. The syndrome was identified by Commander Mike Boyce,188 when he was Commander Submarine Sea Training, as 'Kalmanitis'.189 Another was that, in the years when personal computer technology was in its infancy, perhaps barely born, it took a long time for submarine command teams to adjust and develop anything like the symbiotic working relationship with the new command system that had prevailed with TCSS9. A reason for this may well have been the training offered to officers. Submarine initial training classes were being trained in the command systems but the training received by command-qualified officers who were being confronted by the technology for the first time was far more suspect.190 The Americans, on the other hand, ensured their officers were given thorough and excellent training in their command systems as Dan Conley experienced when at Devron12.191

Whatever the reasons, and because DCA, like DCD, was prone to failures some COs kept a clandestine CEP. Even as late as 1983, when DCB had long replaced DCA, Commander Martin Macpherson, CO of HMS Trafalgar, when she was commissioning had a clandestine CEP installed. Going on board for a celebratory glass of champagne, the then FOSM, Sandy Woodward spied the CEP and berated Macpherson who stood his ground. The two had to be parted by the then First Sea Lord, John Fieldhouse, who reminded them that the occasion was a party. Macpherson got to keep his CEP.192

With these issues unresolved, DCA went to sea in HMS Swiftsure in 1973 followed by HMS Sovereign in 1974 and HMS Superb in 1976. Like all new classes of warship, first of class trials was a lengthy business and the Swiftsure weapon system sea trials did not happen until 1975 and even then, they did not go too well. DCA was not satisfactory.

DCA's get-well programme

In 1974 when John Bench, now a Commander, re-joined the THDS project as Project Manager, now at the Director Underwater Weapon Projects (DUWP), DCA software and DCB hardware projects were in critical states and, with the three submarines already at sea, or about to go to sea, a 'get-well' programme was needed desperately. The situation was exacerbated by the fact that DCA was also the command system for DCB and secondly, the prime-contractor had moved from Ferranti to the, by comparison minnow, Gresham-Lion thereby creating internal project tensions.193 Bench had a formidable task.

The problems for the project then multiplied: the engineers working on the DCB fire control console were out of control so Bench used a simple but practical resolution194; there were many technical issues for example with computer memory, power supplies and the printed circuit boards; and the consoles failed their shock tests. Then Ferranti went into receivership; PPL, suppliers to Ferranti of the only disc that met the sea environment went into liquidation; and finally Gresham-Lion too went into liquidation. But the latter was only a restructuring, Bench persuaded Gresham-Lion to buy PPL and the Ministry of Technology, because of avionic as well as naval activities,195 bailed out Ferranti so as not to endanger the surface fleet command systems programme, almost all of which have been provided by Ferranti.196

The resolution to DCA's BOA ills was to introduce the Kalman algorithms developed by Warner. The decision to take this action was made by Bench and while it was self-evident in the interests of the command system it was a politically brave decision for it meant that "many scientific egos were punctured". 197 Although the ergonomics remained the same, the system now had the capability to deal with 25 contacts at once. But DCA still had to be complemented by TCSS9 which by now was obsolescent and a replacement was badly needed. This was to come in the form of DCB in the late 1970s when it first went into HMS Sceptre.

Missiles join the weaponry inventory

At the same time of the furtive 'get-well' programme the requirement for a submarine launched, anti-ship missile (USGW) was introduced and DCB would have to fire such a weapon. To achieve this, DCB was modified to include 'Matched Search Patterns' which constrained the search pattern of the missile to minimise the target alert time and to reduce the risk of striking non-target vessels.

The initial missile contenders were the French Sub-Martel and the US Sub-Harpoon. The French then offered Sub-Exocet but it would not fit RN submarine torpedo tubes and French reticence to declare details at level 2 excluded the weapon. Sub-Martel was also discounted on technical and performance grounds so the chosen weapon became Sub-Harpoon with development work starting in April 1975.198

Soviet Battle Group tactics demanded a salvo fire of four Sub-Harpoons. Achieving this caused what Bench describes as "the technical fight of the century". 199 The issues focused around the discharge of the weapon from the submarine to achieve the appropriate salvo threat against the target. The technical aspects were exacerbated by lead DUWP Division (RNSH) finding itself at loggerheads with the Discharge Division. After a little démarche and legerdemain by the Discharge Division with MoD and FOSM,200 and the levelling of the situation by Bench pointing out that the Discharge Division's solution would have resulted in four inert weapons being discharged, a resolution was reached and the redesigned discharge sub-system was integrated with the Command and Fire Control Systems.201

A Missile Setting Equipment (MSE) evolved based on an Elliott 920B with three intents: as a risk reduction unit to match to TCSS9 if DCB failed; to investigate the use of commercial microprocessors in a submarine environment; and as a special fit to accelerate weapon trials. It was a success and led to Bench presciently recommending the future use of commercial processors to Vice-Admiral Lindsay Bryson202 who was about to become Controller of the Navy. Bryson, however, took the Ferranti line of large computers as the way forward and indeed the 1600E it went into the DCB derivative, DCC, and the Type 2400 submarines in the early 1990s. Bryson was to be proved wrong.203

DCB replaces DCA

DCB had the same DCA command system based on the Kalman algorithms but with two sets of control room consoles: two Command Consoles, separated by a Principal Coordination Officer's (PCO) station, two Fire Control Consoles and two 1600B computers. The Submarine Weapons Interconnector Sub System (SWISS) accompanied DCB to replace a many TCSS9 units in the fore ends. DCB was fitted in all new build submarines and back-fitted into the DCA-fitted S Class and the Valiant Class starting with HMS Courageous in 1978 where it had to be shoe-horned into the control room commandeering the space of a wardroom shower and intruding into the space needed for the search periscope operator.204

1978 was also the year that the Sceptre sailed from Barrow as the first boat to take DCB to sea. The DUWP project, overseen by Bench, had been at pains to improve the HCI and had , among other things, improved the displays ensuring commonality between the command system and fire control, provided a graphical representation of the tactical picture rather than digital, and created intuitive keyboards rather than the previous hierarchical library structure. Even so, it took time for the symbiotic relationship between system and operator to develop. The Sceptre's CO, Commander Rob Forsyth, was content with the fire control side of DCB but clearly did not trust the solutions being generated by the command side. These issues were exacerbated by there being the A/S 1081 attack teacher, Nemesis, with DCA at Faslane, but no DCB-fitted, attack teacher.205 Forsyth resolved the learning problems in an innovative way: he used the Nemesis staff who were, of course, particularly adept at using DCA in the attack teacher. The fact that the staff were Wrens did not deter Forsyth who took them to sea in the Sceptre so they could generate simulated targets, the tracks of which were known, and compare them with the DCB generated solutions. While it did not alleviate all the doubt, it helped greatly but it must be remembered that Forsyth was of the TCSS generation and, while he found a way to develop a good working relationship with DCB, getting to grips with computer-based command systems was a struggle for many others of the same generation.206

The difficulty was exacerbated by the poor bearing accuracy of the 2001 sonar, although the increase in bearing information being made available to the Kalman algorithms as 2001 was improved and the increased use of towed arrays improved the Kalman generated solutions. Computer memory was also an issue, for DCB used two Ferranti FM1600B computers using 64k memory for the command system and 48k for fire control.207 In an attempt to resolve this particular issue DCB was provided with an automated CEP called Diablo which suffered an operator reaction similar to DCD.208 Then, although clever work had been accomplished to maximise capability into the computer using the Fixpac language, it was prone to the occasional crash which, if it occurred at a critical moment, meant a long, frustrating five- minute wait for the command while the system has restarted.209

DCB in HMS Courageous
Either side of the PCO's console, standing out, are the TMA consoles. The two fire control consoles with their double screens are furthest away
Either side of the PCO's console, standing out, are the TMA consoles. The two fire control consoles with their double screens are furthest away
The automatic CEP, the Diablo
The automatic CEP, the Diablo

The close-range, high-bearing rate scenario

An issue that was present with DCA, but which had been rectified to an extent by Boyce when he was the Submarine Warfare Officer (Tactical Systems), (SWO(TS)), was now prevalent to a greater extent in DCB. This was the inability to deal with close range high bearing rate situations a more - something that had given at least two COs something of a surprise.210 How much the resolution to the problem was a result of the joint RN-USN effort at Devron 12 that studied close detection encounters is uncertain.211

Fortunately, two of the brighter brains in submarines were on hand to resolve the problem. Commander Doug Littlejohns was now SWO (TS) and Warner was on FOSM's staff. They got together and clandestinely co-opted an attack teacher where, over a series of nights of 'tweaking' and testing against initially pre-planned and later open-play tactical situations, they identified some consistent and constant errors which Warner was able to rectify. This was not, however, before invoking the displeasure of the Ferranti engineers but once they realised the effectiveness of what Littlejohns and Warner were doing they all began to work together.212

Just because they had produced DCA and DCB, work did not stop at AUWE. For a start, DCH, which replicated some of the DCB capability and was designed to integrate sensors and navigation had been developed by Ferranti. It was destined for ten O Class submarines starting with HMS Onyx in late 1987.213 The Upholder Class were built in the late 1980s/early 1990s with DCC, another spin-off of DCB, which was planned to be replaced by DCB's replacement system. The four Upholders, however, were sold to Canada where DCC was replaced by Lockheed Martin's CCS 876 compatible with the American Mark 48 torpedo.

DCG: Iterative Target Motion Analysis

Within AUWE, an Iterative Target Motion Analysis (ITMA) had been developed. Although this was based on the same least-squares principle as the original DCA it was improved upon by its iterative process. But its innovation was that it used a PDP 11/44 computer with a disk memory.214 Moreover, it was just in time for some of the submarines to take down to the Falklands including, after the war, HMS Splendid commanded by Commander Tony Smith. Smith wrote an approving report on ITMA and it was subsequently developed as a stand-alone add-on to DCB, called DCG. Its importance, however, was that it proved that military- specific computers like the FM1600B did not have to dominate operational command systems but rather, off-the-shelf, commercial systems could be used practically at sea as Bench had advocated some four or five years earlier. Functionally, it introduced a new man- HCI a or with soft keys and new keypads. It was divided into eight application areas: Target Motion Analysis and Track Management, Oceanography, Weapon Support, ESM, On-board Training, Sonar Support and Confidence Checks. It was a multi-tasking, multi--user machine that could run simultaneous programmes with no relation to each other and for more than one operator. It interfaced with DCA/DCB and had a manual data entry


DCG was developed at AUWE but it was the joint-venture of Gresham Lion, who joined with Cap-Scientific, a software company, to form Gresham-CAP that won the production contract.215

Another, not dissimilar development was yet again a joint RN-USN programme at Devron 12 called JASA. This was the part product of Bill Browning, one of the best mathematical brains in the employ of the USN. It was a desktop calculator BOA and one of its benefits was that it could overcome the less accurate bearing data, or loss of contact and frequency data during towed array instability periods that upset algorithmic solutions. JASA was supposed to be eventually incorporated into DCB and/or SMCS216 and the Americans incorporated it into their equivalent of SMCS, the AN/BYG-1 Combat Control System, (which incidentally adopted a screen presentation very similar to the old TCC analogue version rather than the now prevalent digital presentations) but it missed out on SMCS despite clearly being noticed at senior levels.217 Nor did innovation stop there. Computer programs that made the best use of statistical analysis from SOSUS detections to give the most probable position of a Soviet submarine and an on-board, close range detection training program was another. Both these were American in origin but a British innovation came from Lieutenant Commander Peter Davies called 'Hunt the Victor'. This was a simple computer program to keep tactical skills high during long periods like the Falklands patrols where it was created. But sadly, rather like the 1920s, so many of these useful initiatives lacked mainstream visibility, or, like DCG, development in the right place, and implementation at sea.218

Work begins on SMCS to replace DCB

DCB was still being fitted and being modified to accept new weapons like Sub-Harpoon and later Tomahawk when work started on its replacement with feasibility studies in 1983 under the TDHS project. These moved into two project definition contracts let by CNWSE/DGCC (Chief Naval Weapon System Engineer/Director General Command and Control) to Ferranti and Gresham-CAP.219

Warner had now left the Navy and was working with Gresham-CAP. It was with his influence that an innovative, indeed ground-breaking, solution was presented to DNOR. While retaining the Kalman algorithms Gresham-CAP suggested the use of Intel 386 chips, indeed no less than 150 processors. Their solution also included a reconstruction capability for records. The downside of introducing this function was that the system would require two time bases. But that, in turn, provided an on-board training system which could be run in parallel with the operational system rather than having to shut it down. The company cleverly also took advice on innovations to the fire control system from submarine officers.220

Gresham-CAP were not the only people to take advice. The DNOR Desk Officer responsible, Commander Gordon Leveratt, under the close interest of the Director DNOR, Rear Admiral John Kerr221 and his own Director, Captain Rob Walmsley222 - the project was high profile indeed - had also been taking extensive advice from both within the Service and within AUWE/DUWP. 223 The Naval Staff Requirement that evolved, and from which the specification for the new system was drawn, embraced both the results of the project definition studies and the ideas of the end-users. The proposal that (now) Dowty- CAP presented, and which won the competition after an outstanding marketing campaign224 and a 'Best & Finals' bidding round for which the specification was amended to include Gresham-CAP's innovations, was titled 'Submarine Command System' (SMCS,) vocalised as 'SMACS', and, instead of being given a new three letter acronym, DC'X', the name stayed with the programme. Despite the challenges of producing a vast amount of ADA language software - something of a struggle against the timescales - and the creation of a new operating system, SMCS was in time for the new Vanguard Class SSBN in 1994. It was successfully tested with no problems revealed on the ranges at AUTEC following the first DASO Trident firing.225

SMCS was produced for a new generation of submarine officers for by now the submarine fleet was all-nuclear and its officers were far more familiar with computers having been at sea with DCA and DCB and having been brought up in the age of the personal computer. SMCS capitalised on this by introducing an interface similar to that used in Apple computers, one that would be readily recognised by operators at sea. This was one advantage of the design: familiarity. The second was the extensive use of commercial hardware that meant that hardware could be updated independently of the software. And it was, it went from Intel 386 to Pentium processors and its displays took similar advantage of flat screen technology. An advantage for the Navy was that the new operating system would allow evolutionary modification, potentially saving costs, however it also meant that the Navy was potentially obliged to the contractor. And finally, a true command system that provided all the sonar, command and fire control screens together in the control room thus creating a real combat system that the now properly involved command team could use to greatest effect.

SMCS New Generation

The real benefit of the use of commercial-off-the-shelf technology was realised when it was time to upgrade SMCS. The contract was now with BAE Systems plc who were able to introduce the next generation of command systems, SMCS-NG, into the Trident submarines using standard multifunction consoles running Windows XP on an ethernet LAN in just 18 days.226 Such flexibility, and familiarity for the operators, bodes well for the future of BAE's long-term support programme.


For so many years, as the surface fleet of the Royal Navy developed its fire control systems through the endeavours of Dumaresq, Dreyer, Scott, Vickers, Argo and their Admiralty Fire Control Table, submarine attacking was an inexact science (it probably still is) and had to be achieved solely by the CO's 'periscope eye'. The brilliance of one man, Dunbar-Nasmith and his Is-Was, changed things and introduced a decade of innovative thinking in the 1920s as submarine officers set their minds on the attack problem and how to improve their performance. The 1930s saw the gradual introduction of more technology culminating in the development of the STD, or Fruit Machine, just in time for WW2.

The STD performed well, albeit that both the Americans and Germans had better systems. The change in strategy, employment and tactics for submarines from the surface to the underwater battle that followed WW2 brought with it two decades of steady improvements to the STD with the introduction of the family of TCSS systems from TCSS2 to TCSS9. With that family of fire control and command systems and their collection of nomographic plots submarine command teams became adept and skilled in their use.

The advent of the nuclear submarine, however, brought with it not just a revolution in propulsion but a parallel digital revolution that was to influence so strongly both the sensors and command systems. As the submarine fleet morphed from being all-diesel into all-nuclear so too, the submarine command system took up the digital challenge as an answer to its tactical challenges. The early days were not easy and it took the endeavours of many cerebral submarine officers to resolve the early issues. Also, it took time for the command teams to build any real symbiotic relationships with the DCA, and DCB systems.

With the perspicacious intellect and the innovation of a number of key people within the Submarine Service, the governmental research establishments and certainly within industry, submarine command systems then took a leap forward with the introduction of commercial hardware and the power of its computing capability. The SMCS that evolved has been improved even further and an Astute Class has a command system worthy of the submarine, its weapons and its people.

The evolution of the submarine command system has taken just shy of 100 years and has been forged slowly at first through WW1, slightly faster through WW2 and accelerated during the Cold War and beyond. There are many exemplars for this technological revolution in all walks of life but the 'greatest single factor' remains the same, 'it is the quality of the sailor - the men, and now women, who have to make the systems deliver - rather than the ship that matters'. Has the role of the CO changed? In the early days a submarine was unquestionably CO-centric and this lasted just beyond the end of WW2. Then, with the introduction of the TCSS family matters began to evolve; the CO, though central, was now increasingly more reliant on his command team to develop the attack solution. The nuclear submarine heralded a more delegational style of command; the technological revolution, a plethora of information. The two are mutually dependant. It is up to the command teams of the present submarine fleet to optimise the use and exploit the value of their command systems with maximum effect. That is what 'periscope eye' means today.

I am indebted to all those who have contributed to the writing of this history with their information, memories, opinions and help in various ways. They are: John Bench, Dan Conley, David Cust, Barrie Downer, Alexandra Geary, Peter Green, Alan Heron, Tim Honnor, Roger Trussell, Doug Littlejohns, Martin Macpherson, George Malcolmson, Michael Pitkeathly, David Pollitt, Tony Wardale, Guy Warner, Tony Whetstone.


  1. The name has changed over the years.
  2. Simpson, George, Periscope View, Barnsley, Seaforth, 1972, p.45
  3. Simpson, op. cit. p.167
  4. Coote, John, Submariner, London, Norton, 1991, p. 156
  5. Woodward, Admiral Sandy, One Hundred Days, London, HarperCollins, 2003, P.56
  6. A term that comes from, principally, the Blyth Attack Teacher (later Rothesay) which had a revolving control room in which it was very easy to lose orientation.
  7. Macpherson, Martin, Perisher: The Making of a Submarine Commander in 100 Years Of The Trade, edited by Martin Edmonds, Lancaster, CDISS, 2001
  8. Bacon, Admiral Sir Reginald, From 1900 Onward, London, Hutchinson, 1940, p.54. Bacon was the first Inspecting Captain Submarines, selected and appointed specially for the role. Intelligent and practical, he was a dominant figure in the very early days of submarines laying down some of the principles, notably safety, that have survived to today
  9. Hackmann, Willem, Seek & Strike: sonar, anti-submarine warfare and the Royal Navy 1914-39, London, HMSO, 1984, P.74 The Fessenden gear was fitted initially so that surface ships could communicate with dived submarines.
  10. HMS Collingwood Heritage Collection (CHC) acquired February 2018.
  11. See Sumida, John, In Defence of Naval Supremacy, London, Unwin Hyman, 1989 and Brooks, John, Dreadnought Gunnery And The Battle Of Jutland, Abingdon, Routledge, 2005
  12. The Dreadnought Project acquired January 2018
  13. TNA ADM 1/1376 Use of Dumaresq for speed finding.
  14. Later Admiral Sir Martin Eric Dunbar-Nasmith, VC, KCB, KCMG having changed his name, on marriage to Beatrice Dunbar Dunbar Dunbar Rivers, to Dunbar-Nasmith.
  15. He later went on to command another two submarines, the C7 and D4 before taking command of the E11 in which he won his Victoria Cross at the Dardanelles.
  16. His other inventions include: 1904, a combined elevating and training gear for guns not worked by hydraulics; 1905, a submarine revolution indicator; 1920, the Nasmith-Lockhart Slide Rule; 1922, Varley-Nasmith periscope; and in 1925 he was awarded £600 for the invention of a submarine sounding apparatus that was fitted to 133 submarines. In WW2 he thought of the Rescue Ship idea. 29 of them saved 4000 lives.
  17. The Dreadnought Project acquired January 2018
  19. Lindell, Terry D: The Development of Torpedo Fire control Computers in the Royal Navy in 100 Years Of The Trade, edited by Martin Edmonds, Lancaster, CDISS, 2001
  20. Beach, Edward L, Run Silent Run Deep, London, Hodder, 1955, p. 35. This part of the story is modelled on an old River Class submarine which did not have a TDC but is portrayed as having a Banjo.
  21. RNSM A 1977/ 23/22/174/E8 Rear-Admiral (S), A Museum For Submarine Attack Instruments There is no apparent detailed record of these two initiatives other than that the Ionides Director was similar to the Spencer Director but eliminating certain weak features and that the Spencer Director was a modified form of the Is-Was for 90° Angling.
  22. RNSM A 1977/ 23/22/174/E8 Rear-Admiral (S), A Museum For Submarine Attack Instruments
  23. In the case of the Americans the Is-Was began to be replaced by the Torpedo Data Computer or TDC although the well-researched novel Run Silent Run Deep indicates that the two were often used together.
  24. RNSM A 1977/ 23/22/174/B1 Museum for Submarine Attack Instruments
  25. ibid
  26. RNSM A 1977/ 23/22/174/B3 Range Finding "Fixed Base" Periscope. D'Oyly-Hughes explains why, what appears obvious today, the idea was not adopted at the time. It appears that submarine officers were doubtful of the rangefinders capability from a tactical point of view even though it had been proved to provide better results than any other method in the attack teacher. D'Oyly- Hughes accuses his peers of being amateur engineers predicting difficulties of manufacture which Barr and Stroud had already said were surmountable.
  27. Hall had been Inspecting Captain Submarines previously in 1906-1910 (ADM 196/43 Executive Officers Services) but had been sacked by Admiral Arthur Wilson, First Sea Lord, with whom he disagreed. Churchill said Hall was "A d-d sight too pertinacious" (Churchill, Winston S, Companion Volume II Part 2, London, Heineman, 1969, p. 1365)
  28. The nomenclature of periscopes derives from Barr and Stroud's register book. The FY name derives from its predecessor army rangefinders (the periscope rangefinder was essentially an army rangefinder turned through 90°). The army rangefinders were all designated with the first letter 'F'. Later naval products adopted first letter 'C'. The attack periscope came after naval gunnery range finders by which time they went under the designator 'CH'. The search periscopes came later, hence 'CK'.
  29. Moss and Russell, Michael and Iain, Range and Vision: The First Hundred years of Barr & Stroud, Edinburgh, Mainstream,1988 p. 83 One of the FY1 periscopes was sent to the USA and others were sold to the French Navy and then later an FY2 was sold to the Polish Navy. The rangefinder was on the principles of a stadimeter which uses an image of a target and a known height on the target to determine an angle from which range can be determined. This became the standard way of range finding for British periscopes. American Kollmorgen periscopes tried the stadimeter but reverted to the reticule. The German Zeiss periscopes also relied on a reticule. accessed January 2018 and accessed January 2018
  30. Moss and Russell op. cit. p. 113
  31. RNSM A 1977/ 23/22/174/B1 Nasmith-Lockhart Slide Rule Memorandum from Commander (S) HMS Vulcan at Portland dated 8 May 1921.
  32. RNSM A 1977/23/22/174/B1
  33. RNSM A 1977/ 23/22/174/B4 Combined Slide Rules
  34. RNSM A 1977/ 23/22/174/E 2 Speed Finding Instrument (Garnons-Williams)
  35. Because it was such a large submarine, the X1 always had two command qualified officers, the CO and XO (1st Lieutenant).
  36. RNSM A 2007/557/3/b Submarine Officers Performance Reports. Vol E-L
  37. The known submarines were: X1, K26, L25. Others went to depot ships for submarines: the Vulcan for L Class; the Cyclops for K Class and M Class; the Titania for L Class (three instruments);the Lucia for L or L50 class; the Maidstone for H Class.
  38. Nichols, Jack Philip, Submarine K26, Submarine Service Monthly Report No.1 January 1918, Barrow Submariners Association, pp. 12-16. Nichols wrote "Down the after battery tank there was a little box of special attacking gear. Wheels, dials, sites, scales, knobs, pushes, etc. It was engraved with our Captain's name "Garnons-Williams Submarine Attack Gear". Well, here we were, Commander Garnons-Williams had just got four out of six [torpedoes], a damned good score, but he'd not been using his special bat, the gear was still down below."
  39. RNSM 1977/23/22/174/B8 Cooper's Slide Rule
  40. RNSM A 1977/ 21/26/174/C8
  41. RNSM A 1997/21/26/174/C8
  42. RNSM A 1977/ 23/22 /174/B3 Range Finding "Fixed Base" Periscope
  43. acquired March 2018
  44. Rudenno, Victor, Gallipoli, Attack From The Sea, Sydney University of New South Wales,200, pp.218-224,
  45. Received wisdom is that the Glorious was proceeding independently because d'Oyly-Hughes was in a hurry to return home to court martial his Commander Air. Various books and publications accuse him of being 'cantankerous' and much worse. These accusations are in direct conflict with his personal reports which pen him as an excellent leader.
  46. ADM 196/127/297 D'Oyly-Hughes' Service Record
  47. Branfill-Cook, Roger, X1., The Royal Navy's Mystery Submarine, Barnsley, Seaforth, 2012, p. 43
  48. RNSM A 1977/ 23/22/174/C8
  49. ibid
  50. RNSM A 1977/ 23/22/174/B6 Combined Slide Rule
  51. ibid
  52. Ibid
  53. RNSM A 1977/ 23/22/174/E3 Speed Finding Slide Rule
  54. It is unclear who Millward was. The only Navy List Millward is a Chief Artificer Engineer.
  55. RNSM A 1977/ 23/22/174/E1 Dumeresq for Speed Finding
  56. A Dumaresq was certainly used the submarine X1. Branfill-Cook op. cit. p. 44 I
  57. RNSM A 1977/ 23/22/174/C8 Museum for Submarine Attack Instruments
  58. ibid
  59. ibid
  60. McKenzie, Vice Admiral Sir Hugh, KCB, DSO+, DSC, The Sword of Damocles, Stroud, RNSM, 1995, p. 142
  61. RNSM A 1977/ 23/22/174/B8
  62. Later Vice Admiral, Ruck-Keene was a Captain (S) during WW2 and in command of the depot ship HMS Medway when she was sunk in the eastern Mediterranean on passage from Alexandria to Beirut. He was later to command aircraft carriers his last contribution to the Submarine Service was Chairman of the Submarine Escape Committee in 1946
  63. Email correspondence with Barrie Downer April 2018. Cumming retired in1927 and worked as a Submarine Trials Officer for Vickers in Barrow before committing suicide in 1941 due to overwork and stress
  64. It could well have been the Brewerton Plotting Table or possibly the ARL Table or the work did not start on that until 1924
  65. RNSM A 1977/ 52/174/A2 Plotting Instrument (Lt. Cdr.A. S. Cumming, R.N.)
  66. RNSM A 1977/52/174/A5 but
  67. RNSM A 1977/174/A4 S/M Plotting Pros & [Remarks] Rear Admiral (S) memorandum 4/773/66 dated 2 March 1928 This may have been an improvement on an earlier, smaller plotting board mentioned in the Submarine Service Report No.1 January 1918 pp. 12-14
  68. RNSM A 1977/174/A4 Instructional Officer, Submarine Commanding Officer's Course, memorandum dated 2 February 1927
  69. Ibid Fleet Order 3005: Speed Finding Instrument in H. M. Submarines
  70. RNSM A 1977/52/174/A5 Submarine Plotting Board Mark II
  71. RNSM A 1977/ 23/22/174/A4 S/M Plotting Pros & [Remarks]
  72. RNSM A 1977/52/28 Brewerton Plotter in Submarines-1928. The capital ships identified were the Warspite, Revenge, Hood, Rodney and Queen Elizabeth
  73. RNSM A 1977/52/28 Brewerton Plotter in Submarines-1928
  74. RNSM A 1977/52/28 Rear Admiral (S) Dunbar-Nasmith's letter to the Admiralty dated 16th of April 1930. Boats of that time had a Forbes log that did not perform well at slow speeds; it was being replaced by the Chernikeef log)
  75. RNSM A 1977/52/28 Handwritten minute sheet
  76. RNSM A 1977/52/28 Captain (S), First Submarine Flotilla memorandum dated 7 September 1933
  77. RNSM A 1977/52/32 Submarine Plotting Tables-1924/31
  78. Journal of the Royal Naval Scientific Service, Volume 20, July 1965, No. 4, pp. 61-62
  79. RNSM A 1977/52/32 Letter from the Admiralty to Rear Admiral (S) dated 10 March 1931
  80. ADM 204/87 Admiralty Research Laboratory, Teddington Report of Progress for Quarter Ending 30 September 1932. The tables also became an important tactical device in the anti-submarine war. (Hackmann, Willem, Seek and Strike, London, HMSO, 1984, p. 187)
  81. RNSM A 1977/52/32 Letter to the Admiral Superintendent, Portsmouth dated 22 May 1931
  82. RNSM A 1977/52/28 Fleet Order 2816: Strategic, Tactical and Navigation Plotting-Provision-REPORTS
  83. The Thames Class were the first generation Patrol Submarines and the last effort at producing a submarine that could operate with the Fleet. Of 1800 tons their control room was big enough to take an ARL Table (Akermann, Paul, Encyclopaedia of British Submarines 1901 to 1955, Penzance, Periscope, 1989, p. 305
  84. Barrow Submarine Heritage Centre, An Introductory Lecture to Submarines dated 8th September 1958
  85. Email correspondence with Warrant Officer Michael Pitkeathly March 2018
  86. anning, A E, Steady As She Goes, A History of the Compass Department of the Admiralty, UK, HMSO, 1986, pp. 377-379
  87. OSI Maritime Systems brochure, ECPINS© D-MOP Digital Maritime Operations Plot
  88. Fanning, op. cit. p 379
  89. Commander David Pollitt, Capability Development Manager, OSI Maritime Systems and ex-Royal Navy Fleet Navigator March 2018
  90. TNA ADM 196/54/101 Wadham's Service Record. In fact his career got worse. Despite been promoted Captain in 1935 he was invalided home from the East Indies in 1937 suffering from a nervous complaint while in command of HMS Bideford. His nervous disability pagued him thereafter and may have been the reason for Rear Admiral Wake-Walker to comment that "he is lacking in initiative and loyalty and does not show the inclination or the capacity for cooperation". Wadham was placed on half pay. He later died in an accident in 1941.
  91. The Argo clock company's had been a competitive system to the Dreyer Fire Control Table which was the in-service system prior to the development of the Admiralty Fire Control Table.
  92. Brooks, John, The Dreadnought Gallery and the Battle of Jutland, The Question of Fire Control, London, Routledge, 2005, P.272 and Lindell, Terry D, The Development of Torpedo Fire Control Computers in the Royal Navy in 100 Years of The Trade edited by Martin Edmonds, Lancaster, CDISS, 2001
  93. TNA ADM 196/54/101 Wadham's Service Record
  94. TNA ADM 1/24278 Admiralty Awards Council Case No. 583 the letter is dated 22nd of November 1929. Wadham had only been on the RA (S)'s staff for three months.
  95. TNA ADM 1/24278 Admiralty Awards Council Case No. 583
  96. Young, Edward, One of Our Submarines, London, Rupert Hart-Davis, 1952, p. 34
  97. TNA ADM 1/24278 Submarine Torpedo Director Case No. 583
  98. TNA ADM 1/24278
  99. The Third Hand was the next officer in seniority below the First Lieutenant. The name is submarine lore.
  100. TNA ADM 1/24278 Submarine Torpedo Director Case No. 583 a
  101. Lindell op. cit. Just like the Americans with the Is-Was and the TDC.
  102. TNA ADM 1/24278
  103. There is some contention over Tsoukalas' position onboard as either CO or XO. Hezlet (Hezlet, Vice Admiral Sir Arthur, British and Allied Submarine Operations in World War II, Huddersfield, RNSM, 2001) identifies him as the CO of HHlNS Katsonis other sources have the CO at the time of her loss on 14 September 1943 as variously Commander Athanasios Spanidis and Lieutenant Laskos (certainly the CO when she made her escape from Greece). What is undisputed is that Tsoukalas managed to escape the sinking by swimming ashore and he created an excellent slide rule.
  104. The U-boats captured were: U110, 9 May 1941 (enigma machine captured); U570, 27 August 1941 (HMS Graph); U505, 4 June 1944, (USN); U70, 6 March 1944, (RCN, sank); U1024, 12 April 1945, (sank).
  105. Schäffer, Heinz, U-Boat 977 London, Greenhill, 2017. P.48-49
  106. TNA ADM 199/1890 American Torpedo Data Computer for new design British Submarine
  107. Lindell, op. cit.
  108. TNA ADM 199/1890
  109. Lindell, op. cit.
  110. TNA ADM 199/1890 A Memorandum from DNO dated 27 August 1943
  111. Ibid Minutes of Northway meeting 8 September 1943
  112. TNA ADM 199/1890. Minutes of Admiralty meeting 13 January 1944
  113. Kipper Walker at the Friends of the Royal Navy Submarine Museum, Members' Forum 19 March 2006
  114. The family of TCSSs that were to follow were initially referred to as, for example, TCS S/3 etc. but this was soon changed to the more familiar TCSS.
  115. Fry, Sam, Fruitful Rewarding Years, Stanhope, The Memoir Club, 2006, p. 64
  116. Coote, John, Submariner, London, Norton, 1991, p. 176
  117. TNA ADM 239/437 Advanced Information on Handbook of Torpedo Control System Submarines Mark 3
  118. TNA ADM 263/172 Torpedo and Anti-submarine Fire Control Group Progress Review for May 1955 to May 1956
  119. Besides Barr and Stroud other well-known companies appear in the story of TCCS: for example Westinghouse, Laurence Scott and Evershed.
  120. Moss and Russell, op.cit. P. 165
  121. A canvas tent that caught the water coming down the conning tower.
  122. Conversation with Captain Tony Wardell 30 March 2018
  123. TNA ADM 263/191 Admiralty Gunnery Establishment, Progress Report up to 31 December 1955
  124. TNA ADM 263/118 A preliminary note on TCSS Mark 4 OD 0 (Stage A)
  125. See Hennessy and Jinks, Peter and James, The Silent Deep, St Ives, Penguin, 2015, pp. 130-132 for a good explanation of the Boreas class.
  126. TNA ADM 263/118 A preliminary note on TCSS Mark 4 OD 0 (Stage A)
  127. Branfill-Cook, Roger, Torpedo, The Complete History of the World's Most Revolutionary Naval Weapon, Barnsley, Seaforth, 2014, p. 70
  128. Evans, AS, Beneath The Waves, London, William Kimber, 1986, pp. 405-409. The Sidon was lost when an HTP torpedo exploded as the submarine was alongside the depot ship HMS Maidstone on 16 June 1955.The fitting of TCCS6 is confirmed by Tony Wardell, Electrical Officer of HMS Cachalot on commissioning.
  129. See Hennessy and Jinks' The Silent Deep for a graphic and detailed explanation of both the torpedo and submarine HTP programme. PP.152-166
  130. Interview with Captain Tony Wardale 18 April 2018
  131. TNA ADM 263/182 Admiralty Gunnery Establishment, Torpedo and Anti-Submarine Fire Control Group Progress Review from May 1956 to May 1957
  132. Branfill-Cook, Torpedo, op.cit. pp. 241-245
  133. Interview with Captain Tony Wardale 18 April 2018
  134. TNA ADM 239/715 CB 4901(1) Command Information Handbook for TCSS Mk.6
  135. ibid
  136. Email correspondence with Barrie Downer April 2018
  137. Interview with Captain John Bench 23 February 2018 and John Bench's unpublished notes
  138. DEFE 69/537 a
  139. Tony Wardale tells the story of his CO in the Cachalot in 1960, Lieutenant Commander Geoffrey John Tottenham, who had taken Perisher six years earlier in 1954, ordering the TCC switched off and conducting the attack by eye. It may have been brilliance or bravado.
  140. McKenzie, Vice Admiral Sir Hugh KCB, DSO +, DSC, The Sword of Damocles, Stroud, RNSM, 1995, p. 164
  141. Grove, Eric J, Vanguard To Trident, British Naval Policy since World War II, US Naval Inst, 1987, p. 219 both McKenzie and Grove were referring to two papers: TNA ADM 1/25252 and ADM 205/83
  142. TNA ADM 263/172 Admiralty Gunnery Establishment, Torpedo and Antisubmarine Fire Control Group Progress Review for May 1955 to May 1956. See TNA: ADM 259/436, ADM 204/2015, ADM 204/1921 and ADM 263/1704 how the problem was discussed and evolved.
  143. Coote, John, Submariner, London, Norton, 1991, p. 174
  144. Ibid, Tibbatts could also have been referring to the torpedoes which were woefully inadequate against a dived submarine.
  145. Hezlet, Vice Admiral Sir Arthur KBE CB DSO* DSC, Submarine Operations, Huddersfield, RNSM, 2001, p. 313 and Ballantyne, Iain, Hunter Killers, London, Orion, 2013, p. 17. The U-864 was fitted with a schnorchel (American: snorkel; British: snort) but had an engine that was misfiring and making a loud noise (she was heading back into Norway for repairs). Launders detected U-864 on Venturer's hydrophones (sonar) while she was snorting, confirmed it was a submarine contact when he saw her periscope, and then tracked her by sonar for an hour before firing a four-torpedo salvo at 2000 yards with the torpedoes set at depths between 30 and 36 feet.
  146. Coote, Submariner, p. 175 As the Time Bearing plot had not yet been invented the scaled ruler referred to was probably a Perspex graduated to scales and speeds that was used on the LOP; there are many examples in the RNSM. The rule was later replaced by multi-pointed dividers.
  147. Jones and Roderick, Edward Monroe and Shawn S, Submarine Torpedo Tactics, An American History, Jefferson iNC, McFarland, 2015, pp. 104-107
  148. Later Admiral and Flag Officer Submarines (FOSM),
  149. Email correspondence with Captain Sam Poole November 2017. Poole, along with Guy Warner, was one of the first two submarine-qualified Instructor Officers who contributed so much to the training of submarine officers, resolution of the bearings only problems, and in Guy Warner's case, the development of future command systems.
  150. Later Chief of Staff to FOSM and Rear Admiral.
  151. Later Captain and the first RN submariner to fire a Polaris missile as CO of HMS Resolution.
  152. Email correspondence with Admiral Tony Whetstone October 2017
  153. Fry, op.cit.p. 64-65
  154. Fry, Sam, Fruitful Rewarding Years, A Submariner's Story, Stanhope, The Memoir Club, 2006, P.94 and Interview with Guy Warner February 2018
  155. Wagner, Daniel H, Naval Tactical Decision Aids, Monterey California, Naval Postgraduate School, 1989
  156. Woodman & Conley, Richard & Dan, Cold War Command, Barnsley, Seaforth, 2014, p. 163
  157. Fry, op. cit. p. 47
  158. Wagner, op. cit.,
  159. acquired February 2018
  160. Foutch, JOC Michael, The Ekelund Range: a story of a J0 innovation, determination and communication at acquired February 2018
  161. The reason depends on what value is used for the nautical mile/Pi. The RN's 1936 Range users 6082 feet corresponding to an attitude of about 51.5° i.e. London giving a constant of 1936 whereas the Americans use the internationally accepted agreement for nautical mile of 6076 feet which gives a constant 1934. See Warner, Guy, Do you remember the 1936 Range?, All Round Look Year Book 2013/2014, Friends of the Royal Navy Submarine Museum
  162. Warner, Guy, The Tactical Challenges of Submarine Operations. An Historic Perspective. Part 1 - Before Computer Assistance in The Naval Review February 2016
  163. See Unreferenced document in the RNSM archive. 163
  164. Warner had partnered the Chief of Staff to FOSM, and won.
  165. Woodward, Admiral Sandy, One Hundred Days, London, Harper Collins, 2003, p. 62 Later Vice Admiral, GBE, KCB and Commander of the Falklands Task Force and FOSM.
  166. Telecon with Commander Tim Honnor 14 November 2017
  167. The formal term given to intelligence gathering missions or more colloquially Mystery Trips.
  168. Interview with Guy Warner 13 February 2018. The Approach and Attack Manual was written in 1987 by Dan Conley at STWG (Interview with Dan Conley 15 March 2018)
  169. Email correspondence with Guy Warner April 2018
  170. Email correspondence with Dan Conley April 2018
  171. Ibid
  172. Submarine Courageous Cold War Warrior, the HMS Courageous Society, p. 128, compiled by Mr. Michael Pitkeathly WO(TSSM) and edited by Captain David Wixon Royal Navy
  173. Email correspondence with Guy Warner April 2018
  174. The nomenclature of 'DCA' and subsequent systems indicated: 'D' for digital; 'C' for submarines; and the third letter indicated the sequence of the system. 'A' was thus the first digital system for submarines.
  175. TNA 19 96.10/6/12/13/21 Claisse, Lieutenant Commander J, Tactical Data Handling in the Royal Navy, International Defence Review, 1971
  176. TNA 19 96.10/6/12/13/21 Claisse, Lieutenant Commander J, Tactical Data Handling in the Royal Navy, International Defence Review, 1971 reports that DCA used modified surface ship Action Data Automation and Weapon System (ADAWS) displays but this is questioned.
  177. Email correspondence with Alan Heron May 2018 ex-head of DCA and DCB projects at Ferranti, May 2018
  178. Warner op. cit.
  179. Heron, op. cit.
  180. ibid
  181. Submarine Courageous, op.cit. p. 41
  182. Interview with John Bench 23 February 2018 and his unpublished notes
  183. Warspite's DCD was irreparably damaged in her fire in Liverpool.
  184. Submarine Courageous, op. cit. p. 148 "the much unloved DCD and its computer"
  185. ibid p. 41
  186. Heron, op. cit. For example the Type 21 frigate gun fire control system
  187. Pitkeathly tells the story of HMS Superb, which was also fitted with DCA, going through six light pens within the first couple of weeks of an SNCP patrol. The attack team reverted to the old manual plots. Telecon with Michael Pitkeathy 16 February 2018
  188. Later Admiral of the Fleet Michael Cecil Boyce, Baron Boyce, KG, GCB, OBE, DL, First Sea Lord in 1998 and Chief of the Defence Staff in 2001
  189. Interview with Commander Guy Warner 13 February 2018
  190. Conversation with Commander Peter Green 21 March 2018.
  191. Interview with Captain Dan Conley 15 March 2018. Dan was trained on both the 101 and 117 American command systems. The latter was the equivalent of DCB and also used Kalman algorithms although not in such a sophisticated fashion.
  192. Email correspondence with Commodore Martin Macpherson February 2018
  193. Bench op. cit.
  194. He simply put locks on the laboratory doors one held by the engineers one by quality to prevent unofficial hardware modifications.
  195. Heron, op. cit.
  196. Bench op. cit. Fire control computer storage was increased from 30k to 64k;the PPL disk with 128k was used for overlap programming for slow calculations and provided a reconstruction function; 89 out of 92 printed circuit boards in the DCB fire control sub-system had to be redesigned.
  197. ibid
  198. Bench op. cit. The exclusion of Sub-Exocet followed an acrimonious meeting terminated early by Bench.
  199. ibid .
  200. Bench, op. cit. The Discharge Division went over the heads of the RNSH Division
  201. ibid
  202. Later Admiral Sir Lindsay Sutherland Bryson KCB
  203. Bench op. cit. Later, now Captain Bench, put Ferranti Argus 750 microprocessors in the fore ends modules for Spearfish and RNSH when he was System Project manager Heavyweight Torpedoes. A
  204. Submarine Courageous, op. cit. p. 148
  205. There were, of course, other attack teachers but A/S 1083 Damocles, the first DCB fitted attack teacher was not commissioned until 1980. ( Parry, David, History of the Submarine Attack Teacher, p. 11, available on the Friends of the Submarine Museum website). Nor was there a DCB for the maintainers to train on, merely a mock-up. (Email correspondence with Barrie Downer April 2018)
  206. Ballantyne, Iain, Hunter Killers, London, Orion, 2013, pp. 298-299
  207. Email correspondence with Barrie Downer April 2018
  208. Submarine Courageous op. cit. p.160
  209. Interview with Guy Warner 13 February 2018
  210. Email correspondence with Captain Doug Littlejohns January 2018. He relates how both Rob Forsyth and Rupert Best "were [surprised] more than once by the sudden announcement from DCB that they were about to have a collision with an underwater object."
  211. Conley op. cit.
  212. Email correspondence with Captain Doug Littlejohns January 2018
  213. Downer, Barrie, Notes of DCH Progress Meeting, 9 June 1987
  214. Warner op. cit.
  215. Warner, op. cit.
  216. Conley, op. cit.
  217. Perowne, you are all op. cit.
  218. Conley op. cit.
  219. The company evolutions were convoluted: Gresham-CAP was a 50-50 joint venture between Gresham Lion and CAP Scientific. It became Dowty-CAP when Dowty took over Gresham Lion. Later, BAE took over the Dowty component and Sema took over CAP the name became Dowty-Sema, BAE-Sema and finally BAE Systems when BAE bought out the Sema half. BAE Systems now have the system contract.
  220. Warner op. cit
  221. Later Admiral Sir John Beverely Kerr, GCB, DL and Commander in Chief of Naval Home Command
  222. Later Vice Admiral Sir Robert Walmsley KCB, FREng, FRSA, FIET, Chief of Defence Procurement
  223. Gordon Leveratt identifies some of the people: Barry Sadler, Peter Jeanneret, Peter Davis, DLP (Dai) Evans, Dan Conley, and Tony Smith.
  224. Heron, op. cit.
  225. Warner, op. cit. you are a
  226. Page, Lewis, The Register , 16 December 2008


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  • Rudenno, Victor, Gallipoli, Attack From The Sea, Sydney University of New South Wales,200
  • Simpson, George, Periscope View, Barnsley, Seaforth, 1972, p.45
  • Submarine Courageous Cold War Warrior, the HMS Courageous Society, compiled by Mr. Michael Parry, David, History of the Submarine Attack Teacher, available on the Friends of the Submarine Museum website
  • Pitkeathly WO(TSSM) and edited by Captain David Wixon Royal Navy
  • Schäffer, Heinz, U-Boat 977 London, Greenhill, 2018
  • Sumida, John, In Defence of Naval Supremacy, London,Unwin Hyman, 1989
  • Young, Edward, One of Our Submarines, London, Rupert Hart-Davis, 1952
  • Wagner, Daniel H, Naval Tactical Decision Aids, Monterey California, Naval Postgraduate School, 1989
  • Warner, Guy, The Tactical Challenges of Submarine Operations. And Historic Perspective. Part 1 - Before Computer Assistance in The Naval Review February 2016
  • Woodman & Conley, Richard & Dan, Cold Wall Command, Barnsley, Seaforth, 2014
  • Woodward, Admiral Sandy, One Hundred Days, London, HarperCollins, 2003

Internet sites

Royal Navy Submarine Museum Archive

  • RNSM A 1977/23/22/174/A4 S/M Plotting Pros & [Remarks]
  • RNSM A 1977/ 23/22/174/B1 Museum for Submarine Attack Instruments
  • RNSM A 1977/ 23/22/174/B1 Nasmith-Lockhart Slide Rule
  • RNSM A 1977/ 23/22 /174/B3 Range Finding "Fixed Base" Periscope
  • RNSM A 1977/ 23/22/174/B4 Combined Slide Rules
  • RNSM A 1977/ 23/22/174/B6 Combined Slide Rule
  • RNSM A 1977/23/22/174/B8 Cooper's Slide Rule
  • RNSM A 1977/ 21/26/174/C8 Museum for Submarine Attack Instruments
  • RNSM A 1977/ 23/22/174/E1 Dumeresq for Speed Finding
  • RNSM A 1977/ 23/22/174/E2 Speed Finding Instrument (Garnons-Williams)
  • RNSM A 1977/ 23/22/174/E3 Speed Finding Slide Rule
  • RNSM A 1977/ 23/22/174/E8 Rear-Admiral (S), A Museum For Submarine Attack Instruments
  • RNSM A 1977/52/28 Brewerton Plotter in Submarines-1928
  • RNSM A 1977/52/32 Submarine Plotting Tables-1924/31
  • RNSM A 1977/ 52/174/A2 Plotting Instrument (Lt. Cdr.A. S. Cumming, R.N.)
  • RNSM A 1977/52/174/A5 Submarine Plotting Board Mark II
  • RNSM A 2007/557/3/b Submarine Officers Performance Reports. Vol E-L

Email, Interviews and conversations

John Bench; Dan Conley; Peter Green; Alan Heron; Tim Honnor; Doug Littlejohns; Martin Macpherson ; Michael Pitkeathly; Sam Poole; Tony Wardale; Guy Warner; Tony Whetstone

National Archives

  • TNA 19 96.10/6/12/13/21 Claisse, Lieutenant Commander J, Tactical Data Handling in the Royal Navy, International Defence Review, 1971
  • TNA ADM 1/1376 Use of Dumaresq for speed finding.
  • TNA ADM 1/24278 Admiralty Awards Council Case No. 583
  • TNA ADM 1/25252 Submarine vs Submarine attacks: report of trials
  • TNA ADM 196/43 Executive Officers Services
  • TNA ADM 196/54/101 Wadham's Service Record.
  • TNA ADM 196/127/297 D'Oyly-Hughes' Service Record
  • TNA ADM 199/1890 American Torpedo Data Computer for new design British Submarine
  • TNA ADM 204/87 Admiralty Research Laboratory, Teddington Report of Progress for Quarter Ending 30 September 1932
  • TNA ADM 204/2015, Bearings only track prediction by analogue computer
  • TNA ADM 204/1921 Graphical methods of analysis in bearings only attacks
  • TNA ADM 205/83 Future size and shape of Royal Navy
  • TNA ADM 239/437 Advanced Information on Handbook of Torpedo Control System Submarines Mark 3
  • TNA ADM 239/715 CB 4901(1) Command Information Handbook for TCSS Mk.6
  • TNA ADM 259/436 Determination of range and bearing by timing method
  • TNA ADM 263/172 Admiralty Gunnery Establishment, Torpedo and Antisubmarine Fire Control Group Progress Review for May 1955 to May 1956.
  • TNA ADM 263/182 Admiralty Gunnery Establishment, Torpedo and Anti-Submarine Fire Control Group Progress Review from May 1956 to May 1957
  • TNA DEFE 69/537 Ship Characteristics Committee Oberon Modernisations


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