Maybe you are right, excuse my horrible mistake
If I'm well informed, the German U-Boats were about to wipe out a big part of the English fleet in the Norvegian Sea at the beginning of the war. If the torpedos were not so terribly faulty this would have succeeded and I think that as a result England would not have played any further role in the war, forced into a disadvantageous peace treaty with Germany.
We all know that History is different - indeed by a very close call IMO, due to defective torpedos - what an irony.
Now, what was the technical defects of the torpedos? Impact-type failures? Or failures of the first magnetic-type ones? I'm not an expert in this, and besides: it's not that I care very much about either, but what I know is: These torpedo defections were a turn-around in the European sea war.
In the Pacific region, the USA had similar problems with their torpedos at the start of hostilities. Magnetic torpedos or not? I would have to open a book and not learn very much, except that hitting ships full-broadside (90° angle as I said) was the best technique for minimizing duds; with German U-Boats or American ones!
The Kaleuns had their clock in their hand and gave the fire orders. I don't think they did care about this technical stuff, they didn't have to know, they were confident in their weapon engineers...
Back to SH5:
With the 2 torpedo types that I can chose from at the start of campaign, I'll chose to hit ships full-broadside and a little above the recommended keel depth for best results. If I don't do it, I will score a lot of misses, with magnetic, impact or whatever.