The game is definitely whonky on "collision detection" when vessels are going in reverse, as witnessed in some of the Pearl Harbor incidents of previous versions of FotRSU. A boat or ship will drive right at something, instead of steering away from it... then they will backup a mile and a half beyond what they needed, turn the wrong way, and then back into a dock or another ship, and just keep going until they are merged together. No "collision detection" to the rear... That was definitely an interesting "technique" you used to "launch" your mini-sub...
Now, for merc4ulfate and others with the "damage hiss" sound, is this the one in this video at about the 2:40 mark?
It should go active long about 10pm Eastern time... That is a Gato boat. Now, this Task Force has a very similar makeup to what we were looking for, and thankfully, didn't have more than 7 DD, else I do believe they would have had me. As it was, I was able to sneak right into the middle of the Tafee nose-on - which somewhat surprised me, and we almost didn't get turned and up to periscope depth in time, having been down at 250 below the thermal. All shots hit, but less than half detonated, even though I used impact on all of them, set at 12-18 foot, depending upon my target. I barely got the first shot on the Hiyo, as witnessed by that hole on the bow... The scenario starts at 7:00am, I was shooting by 0842 and depth-charged shortly thereafter. I had gotten away from the DD, no hull damage, only had the 4 rear tubes and the AA guns still damaged. The "leak hiss" sound was still going this time. Only leak is seen above the chief... then the game crashed at 1009 hours, about 20 minutes after I took us off of silent running. I'll try running this a few more times, and see what happens. I've got the Tafee set to spawn 100% of the time, so I should be able to replicate what happens. Is it that sound looping doing it? Is something else spawning right then?...

First impact

Look through the smoke and fire, and see the fifth impact, third explosion on the Jingei Maru

They threw 'em, they dropped 'em

Never very far from me

One finishes, another starts, a third waits...

The three amigos, coming around to do another run on me...