The Mk-14 was the second of the family, dating from 1931. It was supposed to replace the Mk-10 which was then in use. Among the major considerations for this weapon was the its use with the Mk.6 exploder.

    The Mk-14 was in short supply as war broke out, and all torpedoes then in service were fitted with the Mk.6. This resulted in abysmal performance during action. Three main faults were the cause of the Mk-14's initial failure: two were the reasons detailed in the Mk.6 notes, the other a fault in the depth setting mechanism causing the torpedo to run 10 feet deep. This failure was found rather quickly. In June 1942, then COMSUBSOWESPAC Rear-Admiral Lockwood ordered tests conducted at Frenchman's Bay submarine base near Perth, Australia, which proved the suppositions of deep running. However, the USN's Bureau of Ordonance was reluctant to admit to this fact. All regulations to change the problem had to be made in the forces, and Lockwood immediatelys ordered submariners to fire ten feet above their usual settings. On the other defects of the Mk-14, see the article on the Mk.6 exploder.  

    The short supply of the Mk-14 caused problems as well. Submariners were ordered to fire the absolute minimum of torpedoes to achieve their sinkings, since they could not rely on a steady supply. Also, Mk-10 and Mk-15 were, frequently and sometimes, respectively, used in boats. Even the Mk-9 former battleship torpedo (which is not described on this site) was utilized in the S-boats.