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).
Secret memo discussing design requirements for the 40mm Type B.D. gun for use on motor torpedo boats.
| Identifier | ExFiles\Box 176\3\ img047 | |
| Date | 2nd September 1940 | |
| COPY. S E C R E T. 2 To Rm.{William Robotham - Chief Engineer} from Ev.{Ivan Evernden - coachwork} Ev.{Ivan Evernden - coachwork}3/JH.2.9.40. re 40 m.m. type B.D. Gun. We have had several letters and telephone talks to Mr. C.S. Selman of the British Power Boat Co., of Hythe, re the type B.D. gun and its mounting. It would appear that their requirements in the matter of mounting, and ammunition storage do not agree with those laid down by the Admiralty to ourselves, and it seems urgent that the issue be cleared up as soon as possible. Weight will just ruin the M.T. Boat. 1. Ammunition. They propose to carry 300 rounds of ammunition, ex boxes. By so doing they save the weight of 10 boxes each weighing 45 lbs. In this case we should supply the tray as designed, but smaller and to carry 15 rounds. 2. Mounting. We believe that the British Power Boat Co. have been allocated 18 guns, and they would like them to be all of the non-elevating type because this would save approximately 7 cwts. on the mounting. 3. Armour Shields. The Power Boat Co. cannot tolerate the shields as originally proposed and weighing 250 lbs. They propose and have used a small shield about 18 x 20 in special armour plate, .250 ins. thick in front of the gunner's face, as a protection against splinters. We are anxious to get this issued cleared up as further design work is entailed. Mr. Selman mentions that in these matters he has been dealing with a Lt. Cdr.{W. J. Chandler - Chief Clerk} Wellman who is assistant to the Direction of Anti-Submarine Warfare, and a Captain Talbot of the Admiralty in London. These are people we believe we have not contacted so far. We appreciate that the customers are the Admiralty and they it is we have to satisfy, whilst the British Power Boat Co. are the users and can influence the future of the gun. Ev.{Ivan Evernden - coachwork} | ||