I'm no expert in the field, but as far as I've understood the mk14 torps magnetic detonators was so flawed that more often than not they were actually disabled by the submarine crew.
A contact hit is way better than a premature detonation, or even worse, no detonation when at (or rather, under the) target
Whether this is a bug or feature I do not know. In my career, I'm in early '44 and the magnetic detonators should be more reliable. I have at least experienced far fewer premature detonations now at this advanced stage of the war than I did in the early parts (read '42 to mid '43). To the point that I actually think the mk14 is quite reliable and my fish of choice.
I've not tried under the keel shots though at this stage. I got so miffed at all the malfunctions in the early war years, that I got used to going for contact only. I will try it out though on my next patrol.
I loved under the keel shots in SH3. One fish was usually enough on most targets. With contact I need to expend at least two fishes on any given target of medium or greater size. A fish saved, is another 5k-10k tonnage sunk just waiting to happen
