The first chapters of this book describe the early history of gyro guided torpedo development, early torpedo tactics and hand-held steering calculators. Other early chapters briefly describe the development of the Torpedo Data Computers, other components of its torpedo fire control system, and the arithmetic components of the Torpedo Data Computer.
A Torpedo Data Computer performed two major functions: the Position Keeper function and the Angle Solver function. The Position Keeper predicted the present position of the target from prior periscope observations, estimated range to the target, target course, submarine speed, and submarine course. The Angle Solver computed the gyro angle based on the predicted present target and some of the parameters used by the Position Keeper. The characteristics of the torpedo type were also inputs to the Angle Solver. Different torpedo types had different running speeds and turning radii and behaved differently at different submarine depths.
The Torpedo Data Computer was an electromechanical analogue computer occupying a space of approximately 30 cubic feet and housed in the submarine s conning tower. The geometries of the Position Keeper and the Angle Solver functions are illustrated along with the derivations of the Position Keeper and Angle Solver equations and their flow charts. Photographs of all the input cranks and output dials of a Torpedo Data Computer are shown with an explanation of their purpose.
Most of the research material for this book consisted of primary sources, such as Navy manuals from the years 1940-44. Photographs of the TDC were taken on the USS Razorback and USS Torch. An appendix briefly describes the WW II torpedo computers of Britain, Germany, and Japan.
