ABSTRACT
By the end of 1933 Ku¨hnhold had put together the essential characteristics of an acoustic aiming device for the torpedo arm of the Navy. The invention of the sumdifference method gave him a decided advantage for active sound location using microphones spaced relatively closely. A large number of careful experiments were conducted to determine the velocity of sound in sea water under various conditions. It was now necessary to incorporate these techniques and knowledge into a device that would be useful aboard ship for determining in a simple manner both the direction and range for aiming torpedoes.
