After playing around with the new torpedo mechanics, I feel like they have been nerfed a bit much. All of these are fired at a Transport at only 8km so this is an ideal scenario.
3x3 21" oxygen torpedos 7.5% dud chance for size and -5% dud chance for being oxygen-fueled implying a 2.5% dud chance in total. as you can see barely a km after leaving boat only 8 are left, one of them detonated before I was even ready to screenshot it.
4.5km from launch spot, torpedo 3 counting from the left has changed angle dramatically to the right, while torpedo 5 detonated in open water again leaving only 7 with one going far off-target.
Torpedo 2 and 6 veering off-course too at only 6km, a target further than 12km would probably not have been hit be either of those leaving only 4 left without a failureAt 7km, torpedo 4 made contact with the almost stationary,barely maneuvering dummy ship. And it is a dud. It hit the target, it shows 1 torpedo hit in the top right.
While the chance of each individual failure is rather low on its own, its common to see that out of a wave of 8 - 10 torpedos a good 3-5 will experience a technical issue of some sort, be it some sort of deviation from its course (with even a medium-small change in direction making them ineffective, with huge deviations being seemingly more likely), a premature detonation or just a simple dud on the occasional hit. This results that around only half of the 21" torpedos fired even have a chance to get somewhere close, decreasing odds the larger the torpedo is.
In addition to misfires, the overall increase in accuracy of warships, especially secondaries of capital ships makes getting within torpedo range incredibly dangerous. Especially during the late 1910s and 20s with no access to oxygen torpedos, attacks have to be done from a lot further range, thus giving more time for enemies to maneuver, and also more time for a technical failure to occur within the torpedo itself.
I understand that torpedos were laiden with a variety of issues and were not as reliable as we would like to believe in real life, but they did sink ships in quite large amounts. Perhaps lowering the chance for premature detonation or weighing further into smaller changes in deviation would make them a bit more usable.