Appendix IV: Tanks and Capacities
The types, numbers and capacities of tanks given apply to a class in general, as first built, although there may be slight variations within the class.
For convenience the classes are divided into two sections IVA and IVB to cover:
- Appendix IVA - HOLLAND to F CLASSES
- Appendix IVB - NAUTILUS to PORPOISE CLASSES
- Adjusting tanks were originally fitted in connection with the operation of the torpedoes and were sometimes called torpedo compensating tanks, where marked *. After the E Classes the term was used only occasionally e.g. in the L Class and XI.
- Called 'lead ballast compartments'.
- In the A to C Classes, the tanks apparently were not completely filled, probably due to a restriction on the amount of oil that could be carried. CB1815 (1914) gives the amount of fuel carried as 5.9 tons in A5 - 12, 13.6 tons in B1 - 11 and C1 - 18 and 13.1 tons in C19 - 38.
- Includes two 'flooding trunks' of 4.3 tons.
- Includes a 'compensating tank for anchor weight' of 0.4 tons in D3 - 8 and a 'drop weight compensating tank' of 1.95 tons in E1 - 8.
- In the Holland to A13, the lubricating oil was in portable tanks. A 'cylinder oil tank' was first built-in in B2 and an additional 'engine oil tank' in C12. These arrangements would have been fitted retrospectively back to B13.
- A 'fresh water tank' was first built-in during building about C17 and then retrospectively in earlier boats.
- These tanks are main ballast tanks reserved for carrying emergency oil fuel and are included in the number and total capacity of the main ballast tanks.
- Particulars vary between boats. The figures given apply specifically to L18 - 23.
- Eight of the 27 main ballast tanks could be used to carry reserve oil fuel. When this was done, the main ballast water capacity fell by 274 tons and the oil fuel carried increased by 233 tons.
- The capacity of the tanks in tons is based on oil fuel of sg 0.871. In the 1930's this was changed to oil fuel of sg 0.842 and the tons of fuel stowed fell accordingly.
- As built, the oil fuel groups had two spare tanks, which could carry 8.65 tons of oil fuel. These tanks were used eventually to increase the total fuel.
- Used for some other purpose when the gun was removed.
- The tank capacities given are mainly design figures.