Chapter 30: Anchor and Cable Arrangements
30. 1 Anchors and Cables
1. The anchor and cable arrangements in the early submarines were reasonably simple. The Hollands carried one 1cwt stockless anchor and 15 fathoms of 7/16 in crane cable, all manhandled and stowed in the casing. A towing eye was built into the top of the superstructure forward to which the end of the cable was attached by a slip tested to 25 tons and then led aft a few feet and into the superstructure stowing position. The eye was just awash at normal trim but came well out of the water when underway.
In the A Class the arrangements had improved so that the anchor and towing arrangements were separate. The amount of cable gradually increased so that in A5-13 the 1cwt anchor was stowed attached to 40 fathoms of 7/16 in crane cable which had its own slip and arrangements whereby the anchor could be let go with little manhandling. The towing eye was on the hull right forward.
With experience and as the size of the submarines that followed increased the anchor and cable arrangements developed until by 1912 they had become so complicated that the trend became simplification.
2. The B Class carried one 2cwt anchor with 50 fathoms of ½in pitched crane cable. Pitched crane cable was used up to C30 and stud link cable from D1 onwards except in those boats mentioned hereafter with a 'drop weight' when flexible steel wire rope (FSWR) was used on the anchor. All anchors were of the stockless type.
In the B Class an electric capstan was introduced in the superstructure driven from a 5hp motor inboard through rod gearing, bevel wheels etc. The anchor was stowed forward abreast a hinged flap in the casing side with the cable attached and leading outboard and then inboard through a chain pipe to the capstan. From the capstan the cable was led aft to be stowed in the superstructure. This made the operation of letting go and heaving in the anchor reasonably easy. From now on the capstan became a standard fitting, but the anchor and cable arrangements varied between classes and within classes.
3. C1-30 were fitted as the B Class except that they carried two 2cwt anchors, one being a spare.
In March 1908 it was approved to fit a drop weight or statical weight, both expressions were used, in lieu of one of the anchors. Records suggest the change started in C31.
4. C31-38 therefore had one 2cwt anchor with 50 fathoms of 1¼in FSWR and one 500lb drop weight. The drop weight was stowed in a recess at keel level between the torpedo tubes from which a watertight tube led to the superstructure. The weight was attached to 400ft of l¼in FSWR which led over rollers in the superstructure to a drum operated by the 5hp capstan motor. It is stated that 'hand gear operating from inside the boat withdrew a sleeve extension to a stop until the weight was released'. In C35-38 the drop weight might have been increased to 900lb. All drop weights were fitted with a short length of cable to which the FSWR was attached.
At the same time as this change was made two large firing tanks were fitted in the superstructure just aft of the drop weight tube. This made the cable working space extremely congested, see Plate 8. It is undoubtedly for this reason that wire rope was used for the anchor instead of cable. These arrangements must have been unsatisfactory since approval was given in 1912 to fit anchor and cable arrangements in C31-34. One 2cwt Wasteney-Smith stockless anchor was supplied with 60 fathoms of ½in crane cable. The anchor was paid out forward through a hole in the casing which had a sliding shutter to be closed when the anchor was inboard. The cable was hauled in by the capstan and pulled aft by hand over a system of rollers to a cable locker in the superstructure just forward of the bridge. The anchor stowed near the forward bollards. Although the later C boats were fitted, this arrangement was not adopted retrospectively. The cost to fit was £47 per vessel.
5. D1 had been built with the C Class and completed before C30 onwards so her anchor and cable arrangements were on the lines of those in the early C boats. This accounts for the difference between D1 and D2-8.
D1 carried two 6cwt anchors, one being a spare as in all previous boats carrying two anchors, stowed forward in the superstructure one abaft the other and 70 fathoms of ⅝ in stud link cable. The anchor was handled outboard through an opening in the port side and the cable led aft round the capstan, driven by a 10hp motor, and thence to a chain locker in the superstructure forward of the capstan. The cable slip was in the locker and a cable nipper just forward of the locker. D2 had one 6cwt anchor only with 50 fathoms of cable and in addition a 10cwt drop weight with 400ft of 1¾in FSWR.
Later boats of the class were similar to D2 except that the one anchor was stowed right in the bows and had 50 fathoms of 1¾in. FSWB instead of cable. The drop weight was 15cwt and about 15ft from the bows, and was attached to 300ft of 1¾in. FSWR with 90ft of ⅝ in cable. It was arranged as in the C Class except that the mooring drum was driven by a separate 2hp motor. Similar arrangements were fitted retrospectively in D1. A special 'compensating tank for anchor weight' was allocated forward in this class. It is to be expected that the changes mentioned in Paragraph 4 for the later C boats would have been made in the D Class after completion.
6. As mentioned in Paragraph 1 a towing eye was built into the superstructure forward in the Holland boats. This type of towing eye continued until the early C boats. The towing lines were led aft from the towing eye and secured to the superstructure.
In the D Class two towing hooks were fitted side by side in the bows, each mechanically operated from inboard. A short length of cable led from each hook from which the wire hawsers were led and secured to the superstructure sides to abaft the bridge. The mechanical operation of the towing hooks from inboard was fitted retrospectively in A5 onwards.
7. There is little doubt that by now the anchor and cable arrangements with capstan, drop weight with mooring drum, towing wires and towing slips and all the ancillary equipment, was heavy and complicated. In 1912 the Captain HMS BONADVENTURE observed that the anchoring arrangements in submarines required consideration. He stated that 'the Fiat boats (S Class ) carried two anchors with cable which makes for security of the ship, but no weight is wasted on accessories; there was only a hand capstan by which the anchors could be hove up at a guaranteed rate of 12 fathoms per hour. We on the other hand spend an enormous amount of weight for the sake of convenience and do not attain security'. The S Class mentioned was an Italian design incorporating Italian practice. These remarks undoubtedly had effect, but any decisions reached were too late to affect E1-8 then building. A change was made in E9.
8. E1-8 were fitted with a 6^cwt anchor with 50 fathoms of 5/8in. stud link cable and a 1 ton drop weight with 300ft of 1¾in FSWR. After completion 'a full allowance of cable was carried for the drop weight'. This suggests that wire rope had been found unsatisfactory and it is likely that the change was made in earlier boats so fitted.
Plate 13 suggests that from the capstan the cable ran to a chain pipe leading to a tank below the torpedo room flat. This was the beginning of the internal cable locker. Also that a separate warping drum for wires was fitted to the capstan.
9. E9 completed in 1914 started an arrangement which, with minor adjustments, is really the system used in modern conventional submarines. The drop weight was abandoned and never used again. Two 6½cwt anchors were stowed forward, one port and one starboard, in open anchor recesses in the superstructure sides. The capstan motor operated two cable holders, one for each anchor, and also a warping drum for wires. The cable from each anchor ran to its cable holder and then to a chain pipe which led to a cable locker inboard below the main flat. The two cable lockers had a capacity of approximately 0. 7 tons. Fifty fathoms of 5/8in. stud link cable was supplied for the starboard anchor and 15 fathoms for the port anchor. In E17 onwards the latter was increased to 50 fathoms.
The towing arrangements remained the same as in the D Class.
10. The E Class pattern was repeated in the classes which followed i. e. port and starboard anchors in anchor recesses, a capstan and cable lockers but with the size of anchors and size and length of cable varying with the size of the boat. Some typical variations in size from E9 in the classes which followed were Nautilus 12½cwt anchors and 1⅛in, cable, K Class 20cwt and 1⅛in, M Class 15cwt and 1in. , and L Class 8cwt and ¾in. The lengths of cable had started off in E9 with 50 fathoms on the starboard anchor and 15 fathoms on the port anchor, then rose in E17 to 50 fathoms on each anchor and was increased in the L Class to 75 fathoms on the starboard anchor. The K Class had 62½ fathoms on each anchor.
In the L Class the electric motor could raise the cable at 30ft/min.
11. Additions or alterations which came in later classes were:
- The electric capstan was changed to telemotor operation with its own VSG unit. The motor driving the capstan A end was usually also used for some other purpose e. g. an LP blower.
- A winch or warping barrel was fitted aft.
- Typhoon eyeplates fitted forward and aft.
- In X1 the cable lockers were in the externals. The anchors were of 35cwt each.
30. 2 Drop Keel
12. The drop weight fitted forward in C19 to E8 mentioned previously must not be confused with the drop weight in the ballast keel near amidships as it was called originally and which became the 'drop keel'.
13. A drop keel was fitted for the first time in D3-8 and occupied about 11ft of the ballast keel amidships. It was released by a 'dog' at its after end operated from the control room flat. The forward periscope was offset 6in to starboard of the middle line to clear the drop keel release gear.
In the E Class the drop keel was released from its forward end with the gear right under the periscope. However, the periscope well was extended to port to allow the periscope to remain on the middle line with the drop keel release gear angled to clear.
Some typical sizes of drop keels were:
|V Class||5 tons|
|E, G & L Class||10 tons|
|NAUTILUS; K & M Class||20 tons|
|X1||Two of 10 tons each, one well forward and the other well aft of amidships.|
14. From its first adoption the drop keel had been released by hand until in Oberon and perhaps X1 a telemotor operated clip was fitted in addition. Doubts later arose as to whether the telemotor clip was foolproof and justified. It was removed on the recommendation of RA(S) in 1927 and the hand gear only retained. During the Second World War drop keels were welded in place so that they could not be released. A drop keel was not thereafter adopted in new designs.