mysterious unexplained catastrophic damage

[popeye]

So, I'm fresh out of pearl, and have been ordered to the south china sea, to sink some jap ships, and two freighters sail right up to me. not seeing anyone with any naval guns lurking about, i opened fire with the deck gun, and got my first 5000 tons.

an hour or so later, a bigger freighter sails across my path. i gave him a torpedo, before several rounds from the gun sent him to hell.

now withing a few hundred miles of my deployment zone, i set course. just as day come up, and i'm wondering if i should dive to hide from any air patrols, i see an airplane. he is not on course for me, so i have time to crash dive before he makes any attack.

heres where it gets weird.

at about 90 (meters) i started getting severe damage reports, and then my sub asploded. all hands lost.

i didnt hit anything, and i was too deep to get hit by the plane. it was like i sailed into the bermuda triangle.

any idea what got me?