Pitcairn's Director was a "very ingenious but intricate design" for a torpedo director based on worms, worm shafts and gear wheels. It was invented by Lt. R. F. Pitcairn (retd.) and found unsuitable for service requirements despite its automatic, self-setting nature.
Criticism and Appreciation
Although the Royal Navy would discontinue any use of the Tangent Arm in 1915-1916, Pitcairn's device was criticised for lacking one. Instead, rather than adjust the director angle to converge on the target, it merely indicated to the operator by a scale and pointer how many feet to left or right of the target he should aim. Vernon felt that this was more difficult a task than the alternative, which required the range to the target to be judged and entered onto the tangent arm.
The telescope was held in double trunnions so it could be trained or elevated without disturbing the director. A set of locking allowed it to be aligned again shortly before firing.
- Annual Report of the Torpedo School, 1911. p. 45.
- H.M.S. Vernon. Annual Report of the Torpedo School, 1911, with Appendix (Wireless Telegraphy). Copy 15 at The National Archives. ADM 189/31.