Longmore's Disc was a disc developed by a versatile young Arthur Murray Longmore that could be added to a British Torpedo Director to permit the crossing angle between the enemy and the torpedo bar to be read off directly.[Citation needed]
It was not a bad idea, but not the best idea. It was fitted on Torpedo Director Pattern 2380, but upon the creation of Robinson's Disc in 1914-15, it was to be replaced on these directors with that disc (which measured the angle between enemy heading and line of sight... the Inclination).
- Torpedo Director
- T.O. No. 124 of 1915
- Annual Report of the Torpedo School, 1915. p. 59.
- H.M.S. Vernon. (Jan 1916) Annual Report of the Torpedo School, 1915. C.B. 1166. Copy 1025 at The National Archives. ADM 189/35.