Middleton Plotter

The Middleton Plotter was a torpedo control device conceived by Lieutenant (T) J. R. Middleton of H.M.S. Hercules.

Its goal was to automatically indicate when to fire, without requiring calculations to find the bearing rate or to then find the deflection. After promising preliminary tests, in 1913, two sets of equipment were ordered from Elliot Brothers.

It consisted of a telescope or periscope which would be trained to stay on the target by a hand crank. A worm gear would read this angle and then use a disc-and-roller variable speed drive set to the bearing rate being applied. A gyrocompass receiver would act through a differential to remove own ship's yaw. A mechanical calculator would then take the total deflection and subtract out the portion of the deflection attributable to own ship's motion only. The operation was by entering the speed of torpedo, sped of own ship and mean range to the target and then work the handcrank to keep the scope on the target. When two electrical contacts touched, it was time to fire the torpedo.

Rice's Torpedo Automatic Sight was viewed as a contingent system to be developed in case Middleton's proved unsatisfactory.

By the end of 1915, one of two sets of the equipment was still under construction. While there were plans to see one trialled in H.M.S. Iron Duke, the extreme cost of the first delivered unit prompted the decision to drop the project. The first and possibly only unit created was allocated to Vernon.

See Also

• Dreyer Fire Control Table
• Rice's Torpedo Automatic Sight

Bibliography

• H.M.S. Vernon. (Feb 1914) Annual Report of the Torpedo School, 1913, with Appendix (Wireless Telegraphy). Copy 42 at The National Archives. ADM 189/33.
• 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.