From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Letter to The British Power Boat Co. Ltd. concerning the specifications for 40 mm, type BD gun mountings.
| Identifier | ExFiles\Box 175\3\ img004 | |
| Date | 7th August 1940 | |
| C. to m.{Mr Moon / Mr Moore} Ve. Rm{William Robotham - Chief Engineer}/FJH.{Fred J. Hardy - Chief Dev. Engineer} Rm{William Robotham - Chief Engineer}/CTS.{C. Trot Salt - Carburation} for Blk. Fr.6/JH. 7th. August, 1940. The British Power Boat Co.Ltd., Hythe, Southampton. For the attention of G.C. Selman Esq. Dear Sirs, re mountings for the 40 m/m.{Mr Moon / Mr Moore} type BD{Mr Berend} Gun. We thank you for your letter of the 2nd. instant ref. GCS/MN re the mountings for the Bofors gun. The first 36 guns will be single shot, and will weigh approximately 190 lbs. complete. The mounting which will be Oerlikon type SYMA weighs 10 cwts. We have been asked to provide a tray for a box of 30 rounds of ammunition carried on the mounting. This when full will weigh approx. 150 lbs. A single round weighs .86 lbs. and the box 45 lbs. We were given to understand that the Naval Authorities would not welcome a proposal we made to carry loose ammunition on the tray, as they wished all live ammunition to be in the regulation boxes. We gather from your letter you are catering for 300 rounds, ex boxes and would welcome advice on this matter. The original armour shields carried on the mounting for the gun and proposed by the Naval Authorities weighs 250 lbs. Ther is every chance that this weight may be reduced. Subsequent guns to the first 36 will be on a non-elevating mounting shown on CL.124 of which you have received prints. Its weight will be approximately 360 lbs. The weights of the ammunition and tray and the shields will be as previously stated. The cradle of the gun will be in Naval Bronze instead of aluminium alloy and the weight of the gun will increase from 380 lbs. to 480 lbs. (estimate only). p.p.c. | ||