Torpedo Availability and recommendations

[Arclight]

There's a clue on wiki:

In 1923, Congress made NTS Newport the sole designer, developer, builder and tester of torpedoes in the United States. No independent or competing group was assigned to verify the results of Mark 14 tests. As torpedo shortages cropped up (despite three shifts of three thousand workers, production at NTS was only 1½ a day in 1937, and only two thousand submarine torpedoes were built by all three Navy factories in 1942), NTS was unable to increase production, for there was no room, and they were already working around the clock, "falling critically behind schedule nevertheless".

http://en.wikipedia.org/wiki/Mark_14_torpedo

Even older Mark 7, 8 and 9 torpedoes were still used during WWII;

http://www.navweaps.com/Weapons/WTUS_PreWWII.htm