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Submarine Living

Living Conditions and Hygiene

From the very nature of her mission and throughout her history the submarine has afforded what can only be called sub-standard accommodation. The inevitable crowding of an average H.M. ship messdeck becomes spacious in comparison. Officers and ships' company live in conditions which are best likened to caravanning with a space reduction to one-third that of normal, much reduced headroom, and complete exclusion of daylight. Gadgetry abounds, and controls of all kinds obtrude in the most insistent fashion into what are primarily living spaces. To open a locker or cupboard usually entails disturbing messmates who are using it as a seat or a bunk, so a cheerful acceptance of all this is most important. Hot bunking may be necessary at times, but is less common today than in the past. This picture of living 'like herring in a barrel' is further aggravated when a submarine stores for war-or even a long patrol in peace-time. The wooden boxes of tinned food are stowed as a false deck in the gangway for the whole length of the submarine and progression is in a more crouched position than ever.

Wash places are pretty scrimpy affairs and no showers are available. In fact, personal cleanliness is difficult to maintain, and some may be tempted to give up the struggle, especially if the requirement to be ready to turn out immediately necessitates the miserable business of sleeping in one's clothes for days on end. Hygiene on a long patrol may be further jeopardized by the need for water rationing, and in some of the older classes of submarines still running, less than a gallon per man per day for all purposes (including cooking) may be the ration. In such circumstances the collection and sterilization of the water from the air conditioners is justifiable for at least some purposes other than that of drinking. The present design of submarine heads is deplorable. Far from obtaining the optimum crouched position for defecation, they achieve something like a high perch with semi-extended legs and the head forced forward by the curve of the pressure hull behind it. Small wonder that constipation is virtually an occupational disease of submariners.

The growing complexity of electronic equipment also has a material bearing on habitability. Its demands on space are substantial and consequently reduce that available for the accommodation of the personnel whose duty it is to use and maintain it. All of it generates heat. In patrols in the colder waters, this is not unwelcome and, in fact, it may be a convenience to have a warm amplifier on which to hang a wet pair of gloves when one comes down from a watch on the bridge.

In warmer climes the extra heat is an extra burden to be borne by the air conditioner-if, in fact, this asset of habitability is permissible at all! In some states of operational requirements it is not. In many submarine exercises of today, the main problem set and exercised is one of detection, and in our modern submarine fleet there have been great advances in the Asdic. This is now a passive set of great sensitivity, but, if it is to give the optimum results, calls for the acceptance by all on board of a very arduous regime. The 'ultra silent' state has been introduced in a fashion seldom previously attempted. In this, all machinery is stopped and any movement of personnel about the boat is discouraged.

In fact the whole of the ship's company, less a mere handful of men in the control room, are encouraged to assume the horizontal in their bunks. At most times this would be a not unwelcome instruction to the average rating, but in practice the air conditioner is switched off and the temperature of the sea water may well be in the eighties. No extraction of moisture is taking place, and the water content of the atmosphere is being built up by the accumulative evaporation from the sweat-laden skins of 70 humans. And all this in addition to the fact that the atmosphere, when first taken in as fresh, was probably humidity-laden. In such circumstances temperatures of over 100 degrees F associated with humidity of up to 95 per cent are common. Naturally, the worst of all is the Asdic operator's cabinet which becomes something of a torture chamber in which the key rating of the moment is expected to produce mental concentration of a very high order.

A common routine might be to remain in the ultra silent state for five hours, snort for one hour, five hours silent again, and so on over a period of days. This is an exacting requirement and might well strain the morale of even the most well-knit men. Remember also that the atmosphere taken into the boat during its one hour snorting period is not country fresh air but is laden with moisture from particulate salt water spray, which the separating device in the snort mast is powerless to exclude. The immediate close-down of all machinery, including the air conditioner, means that removal of this atmospheric moisture is not possible, and the ensuing five hours of submergence in the silent state, starts off with a high-base-line all ready for the build-up.

Here we have this picture of bunk-bound personnel wallowing in their own perspiration with little to be done about it. Even the relief of air movement is denied, for fans and punkas are idle. The solution of air conditioning machinery which is silent appears to be technically remote if not impossible of achievement. The immediate measures of relief which might be given are limited. Naturally, clothing is abhorrent and only minimal covering in the nature of a loincloth or sarong is tolerable. We might furnish the latter in a lightweight material perhaps even disposable. To lie on, nothing is better than the split bamboo or rush mat of pre-war Persian Gulf days. At least, it channels the sweat and gives the tortured skin the solace of resilient firm smoothness instead of the sticky adhesion of a saturated sheet which makes turning or any change of position a miserable business. Some even claim that it minimizes the prickly heat which is the inevitable acquisition of all but the extremely immune.

At this point, it is well to emphasize that air conditioning in submarines is not solely, or even primarily, for the benefit of the personnel embarked. It has a most important function in the protection of equipment. Much of the complicated electrical and electronic gear is prone to deterioration in moisture-laden atmosphere, and its expectation of life much curtailed. Earths are a commonplace, in some situations insulation can be so circumvented that a very real hazard to life itself is presented.

The Americans take such a very serious view of this aspect of the control of atmospheric moisture that their provision of air conditioning is on the lavish scale. In the modern nuclears its capacity is in the region of 240 refrigerant tons -and, of course, such a power requirement in these ships is easily met. As a measure of their concern with this problem it is mentioned in passing that one very advanced thinker there has propounded the idea of providing the Polaris boats with an atmosphere of helium and oxygen for the duration of their patrols. This on the score that this lighter gas would place less load on their air conditioners. Naturally, all of us here would find difficulty in visualizing this as physiologically acceptable or justifiable. It is an index, however, that in some minds, machines come before men.

Air Purification

I wish at this point to confine my remarks to conventional submarines. Air purification is a very different matter when we come to consider nuclear sub marines later on.

In effect, the simplest form of air purification is to surface and ventilate and to do so before the air has become too foul. This was the inevitable practice of the early submarines and their operational employment usually permitted it Later on, when fear of enemy attack required longer submergence to evade it the first primitive attempts at air purification consisted of spreading out sod; lime on trays, and hoping for the best. We have progressed since then, but let us not be too smug, there's still much room for improvement.

To be basic, the problem consists of removal of carbon dioxide and replenish ment of oxygen before excess of the former or lack of the latter begins to have detrimental effect. Like most measurements applied in relation to the human body, accuracy is difficult to achieve, but by reasonable experiment our physiologists have given us an arbitrary limit to work to. The accepted limits of alertness are 3 percent CO2, and 18 per cent 02. Even so it is not really desirable for the human frame to be exposed to this variant from normal, but opera tionally it is accepted if only for the conservation of the stores necessary to effect control.

Reliability of judgment begins to be affected when the oxygen level falls below 18 per cent. Replenishment is then essential. The Americans do this by carrying bottled oxygen outside the pressure hull and bleeding it in as required We, in the Royal Navy, generate it from oxygen candles composed of sodium chlorate and iron filings, and this method is beginning to win favour with the Americans too. The time to commence oxygen generation varies with the class of boat and the number of men on board, but to give a rough idea it is around 15 hours after shut down for a Porpoise Class boat with a normal complement and 11-12 hours for the older submarines.

Carbon dioxide absorption can be deferred for about two hours longer, since the volume of 02 consumed per man is greater than that of the CO2 evolved These calculated times are not observed should the CO2 indicator reach a figure of 3 per cent. This in itself is always a signal for the commencement of air purification. Further, if while the air purification equipment is running, the figure of 3 per cent is touched, then it becomes imperative to increase the rate of its functioning.

Carbon dioxide absorption has advanced from the days of soda lime spread out on trays-the principle is the same, only better organized. It is achieved by passing the air through absorption units each of which has four canisters containing 15 lb of soda lime. Each canister has a limited life, clearing some 16 cu. ft of CO2, per hour for the first two hours and then tailing off considerably Air purification stores to be embarked for a long patrol are not negligible, and their suitable stowage becomes a very real problem indeed when one remembers that they must be readily accessible. Room may have to be found for some 122 oxygen candles and 192 soda lime canisters at the outset.

Snorting

The Schnorkel mast is about 16 years old. The Germans introduced it operationally in the last year of the Second World War and all our post-war submarines have adopted it. It was developed because of the success of radar in detecting enemy submarines on the surface and enables running on engines while still submerged, so charging batteries without surfacing. This is an operational and technical achievement of significance, but one that is associated with side effects on habitability which are of concern to us.

Snorting is not fun. It creates a negative pressure inside the submarine which is not necessarily constant in degree-in fact it may well vary from minute to minute if the trim is difficult to keep in a rough sea and the mast head is dipping. For those who have to make a conscious effort to clear their ears this becomes a repeated botheration, while the abrupt changes can well awaken the non-duty watch from sleep.

Another point to be remembered is that the vacuum created by snorting is reducing the partial pressure of the available oxygen in the air of the boat. For this reason, the continuous snorting vacuum must not be dropped below 25.75 in. Hg-the point at which a 21 per cent concentration of oxygen becomes equivalent to 18 per cent at normal atmospheric pressure-the limit of alertness, mentioned before. For the same reason it is essential to restore pressure in the boat after snorting and before undertaking prolonged dives without access to the atmosphere.

Victualling

When showing visitors round a submarine, the females in the party never fail to gasp with astonishment that the cooking for 60 to 70 men can be achieved in the limited space provided. Yet good food, well prepared, is more important than ever in a daily routine characterized by much monotony. The Admiralty recognizes this by certain special provisions for submarine victualling.

The messing allowance itself is not increased, but the depot ship carries a stock of special victuals which includes pre-packaged fresh vegetables, boneless beef in special cuts, and pre-cooked frozen foods-such articles being issued at no extra cost. In addition to this, on longer patrols, the submarine is entitled to draw certain traditional 'submarine comforts' free, e.g. fruit juice, soups, cocoa, tinned milk, extra cheese and some tinned meats. Under these conditions too, there is no separate wardroom catering, officers and men having the same menu at almost all times.

The Maintenance Cycle

Work study having been introduced into the Navy, for better or for worse, one of the first tasks which it was set was to examine whether any improvement was possible in the proportion of operational time available in the submarine service. The quite disproportionate amount of time being spent maintaining and giving leave was causing some anxiety. This largely, was due to observing the three traditional leave periods each year, and then having to break into the 'term' periods for maintenance.

The solution which has been evolved is a rotating cycle in which a submarine operates for six weeks, and maintains for two out of every eight. Leave is taken during the maintenance period by part of the crew-up to the recognized annual maximum. The scheme has its drawbacks and unpredictable defects may rudely interrupt it. 'Squadron life' too is discouraged and fond parents can't always be on leave when their children are home from school.

Against this must be weighed a claimed 14 per cent increase in operational availability, and the abolition of the certainty of a potential enemy being able to count on none of our submarines being at sea during conventional leave periods.

NUCLEAR SUBMARINES

From this point much of the information used will be from U.S. sources. This is inevitable, but they produced a Rickover and we didn't-its just as simple as that. Though beholden to the Americans for their pioneering in this field, let u not be downcast-they have had good things from us in the past, e.g. the angle, flight-deck, the mirror landing device and the steam catapult.

When Nautilus put to sea in 1955 she represented an engineering achievement of the very greatest military significance. Uranium fission is a non-oxidative process independent of an air supply, and the true submersible had arrived on the scene. The conventional submarine's submergence had always been limited by the capacity of her batteries. In the nuclear, the only limiting factors to submergence can be listed as:

(a) air purification supplies

(b) food

(c) human endurance

Those under (a) above are being resolved, as will be shown presently and only (b) and (c) are really operative today.

Because of sound engineering practice, radiation control afloat has been no great problem and is of significance only in periods of building and repairs Nevertheless, vigilance must be ceaseless.

When nuclear submarines first put to sea, the medical officer's interests and responsibilities centred around the problem of radiation control. This was patently no problem at all and it is on record that the radon from the radium dials and wrist watches was the most prominent source. The reactor itself was no problem. Radiation control, however, has reappeared as a problem, not in the submarine at sea, but in the depot ship. Submarines may come in from sea in rotation, each with some small job to be tackled in the reactor compartment.

This necessitates the employment of skilled artisans on a section of the circuit which has been freezed sealed and no matter how well the pre-planning is done some exposure is often inevitable. The limit of permissible exposure is rigid- 12 rems a year and not more than three in any quarter. A particular jot might have to be abandoned short of completion because the depot ship has run out of artisans with the necessary skill and with their exposure limits not exceeded. Or again, the depot ship may be in the position of requiring to reject a job in the next incoming boat for similar reasons. The responsibility of enforcing this rigid control of the radiation exposure lies with the Senior Medical Officer of the depot ship and must never be lightly discharged.

First of all let us examine the claim that the problems of air purification art being resolved. From what has been recounted already in the case of the con. ventional submarines, it is clearly a case of coping with a degree of CO2 build-up and oxygen depletion, relative to the expansion of dived time from an average of eight hours or so, to one lasting weeks. If we were still confined to thinking in terms of soda lime canisters and oxygen candles then the outlook would be dim. Fortunately we are not and, aided by the well-nigh limitless power at our disposal, more reasonable solutions are at hand.

Carbon Dioxide Elimination

A closed circuit regenerative chemical process has been evolved, employing Monoethanolamine (MEA) which is sprayed from the top of a scrubber tower meeting a flow of devitalized air. The MEA forms a weak chemical bond with CO2 of the air and so removes it and falls with it in solution to the bottom of the tower. From here it is pumped to a heater where, under increased temperatures, it releases the CO2 to be pumped overboard. The heated amine can now be cooled and returned to the top of the scrubber tower to begin the whole process over again.

It all sounds most beautifully simple and effective and we are told that it remains so, but only just so long as the piping is leak-proof. The amine agent employed is toxic and must not be allowed to contaminate the boat's atmosphere.

When nuclear submarines first did their prolonged dives, it was deemed satisfactory and tolerable if the CO2 percentage was kept down to 1 per cent. With increasing experience, it is usually now closer to 0.5 per cent and the general opinion among physiologists is that this should be devoid of any ill-effects even over periods of months.

Oxygen Replenishment

The Americans have evolved an electrolytic process which generates oxygen from water. As water is relatively unlimited, and electrical power abundant on board a nuclear submarine, the ideal would seem to be achieved. However, the Treadwell high-pressure oxygen generator is bulky, weighty and expensive to produce. The original capacity of 75 cu. ft of oxygen per hour is less than ample to carry the submarine's full load, and requires supplementing from either of the two traditional sources above. Improved models with a capacity of 120 cu. ft per hour are on the way. Research goes forward for improved methods and among the promising runners must be mentioned:

(a) The 'split-cell' type of generator

(b) The photo-synthetic cycle of green algae-does both oxygen production and CO, absorption, but very, very inefficiently

(c) The sulphate-cycle system. Aqueous solution of sodium sulphate is split electrically into oxygen and sodium hydroxide. The latter can be used to absorb the CO, and the sodium sulphate subsequently regenerated. This is promising but not yet of practicable application.

Carbon Monoxide

This toxic hazard was not unknown in the conventional submarine, the commonest factor in producing it being defects in the snorting drill and, to some extent, cigarette smoking, though this was only to a very minor degree as the eight to twelve hour dive did not furnish the time for a build-up.

The early days of the nuclear submarine were attended by a 'blind-spot' for this gas as a hazard. It was assumed to have departed with the Diesel engines. The provision of an atmosphere with full normal oxygen content, ensured that tobacco burned quite easily, whereas in the conventionals smoking was virtually self-limiting when the oxygen percentage dropped to around 18 per cent by reason of its non-combustion. Anyway, the first 36-hour dive of Nautilus showed a CO content in the atmosphere of 100 p.p.m. and a sizeable problem was on hand and required urgent attention. This has been met fairly satisfactorily by the provision of CO 'burners' which, in the presence of a catalyst, converted the CO to CO2 which in turn is eliminated by the CO2 scrubbers.

The problem of what is a permissible level for continuous exposure for weeks at a time is quite suitably exemplified by this CO problem. The Americans have set it at 25 p.p.m., and they record that the frequent headaches which are recorded on their long dives are probably attributable to instances where the burners are incapable of achieving this level.

Freon

This gas enters submarine atmospheres from the refrigerators and air conditioners. The systems employed in submarines were not the hermetically-sealed types employed ashore, for reasons of accessibility for repairs, and small leaks had been known in the past. The gas itself is relatively non-toxic having an eight-hour permissible limit of 1000 p.p.m. However, its decomposition products are much more toxic, and these are produced by the CO burners. Under their influence Freon can be transformed into such unamiable products as phosgene hydrochloric and hydrofluorin acids, chlorin and fluorine. The only answer is leakproof systems for Freon.

Hydrocarbons

In an atmosphere of machinery, the presence of some hydrocarbon is to be expected. The lubricating oil itself would produce them. But these hydrocarbons are of the aliphatic and relatively non-toxic type. It was when concentrations of the more toxic aromatic hydrocarbons (benzene type) were found during the Nautilus habitability cruise that eyebrows were raised, and the hunt was on.

Two prominent sources easy to spot and eliminate were the Bluebell metal polish and deck wax. They required to be banished forthwith. Less promptly incriminated, but eventually run to earth, were the solvents used in the oil-base paints, and now no use of such paints without a proper venting time of weeks before the next dive is permissible. Better still, is to plump for the use of water-based paints alone, provided they can be made efficient.

Enough has been said to make it clear that the control of a submarine's atmosphere on a prolonged dive is a very complex matter. Constant vigilance is required, and this is effected in the modern nuclear submarines by the air analyser, the console of which is sited in the control room and which can 'sniff' and analyse the atmosphere from all compartments. At present it measures 02 and CO2 percentages, and registers the presence of CO, Freon and the hydrocarbons. These are the five which have been chosen to be dealt with in some slight detail above, but the list of potential contaminants is very much greater and every item of stores destined to be embarked must be assessed with great care as to whether it is a potential hazard.

High on the list of possibilities are: mercury, nitrogen oxides, arsin stibine, hydrogen sulphide, sulphur dioxide, chlorine, trichlorethylene, carbon diosulphide, and formaldehyde.

In short the whole set-up is a vertibale toxicologist's picnic!

Air Conditioning and Improved Hygiene

The actual propulsion machinery on board nuclears is steam turbine and this, with its unavoidable steam leakage into a sealed submarine atmosphere, would soon create unpleasant humidity conditions. To combat this and to counter the extremes of sea water temperatures met with, air conditioning is essential and, fortunately, with the unlimited power available, it can afford to be on a lavish scale.

The maintenance of level temperatures and humidity leads to an improvement in the hygiene conditions on board which is quite revolutionary, and this is supplemented by unlimited water supply for bathing and laundry. Normal shore-side personal hygiene becomes possible and the usual crop of skin troubles associated with prolonged submergence no longer appears.

In short, the physical health of the submariner in a nuclear boat need not be impaired by his environment. Can the same be said for his mental health after weeks of boring submergence? Time will show and, on that indeterminate statement, it seems appropriate to close.

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