It’s very likely that the torpedoes did not work for the whole war really. It sometimes is scary to think about all the complaints sub commanders put in, only to be dismissed by the Department of the Navy as excuses for bad leadership or tactics. I get that you have to take this line sometimes but still... That being said it should be noted US Naval strategy has never particularly relied on subs or been that great at…
The patrol reports of each sub detail pretty well what shots were taken and after the fixes in '42 and early '43, the hit percentages rose dramatically... 1944 and 1945 were very good hunting times for US subs in the Pacific. They sank an amazing number of targets in a very short time.
(Former US submariner and very amateur military historian.)