Wow, this could be bad if subs were as ridiculously damage-proof as some people say....

i might use it when i have to surface and a destroyer is trying to kill me. It will
probably take at least 9-10 rounds right?

They're also insanely inaccurate anything farther than 5 or 10 degrees. And you get a
total of 40 rounds any way you cut it.

Not saying that it isn't overpowered, but it's certainly much less so than the platform
that it's mounted on.

I've had my 900 SD Brooklyn sunk by Laoji's IJN sub (2 deck guns) in about 11 seconds
while sitting on top of him to prevent getting torped.

Deck guns work. And like everything else on the submarine, are vastly more powerful
then anything else of their level/size.

Basically, they're KM 11" with a better reload and a smaller splash.

Thanks LK =D

Each shell does upwards of 800-1100 damage to a ship.

It's perfectly possible to sink CL's and below using only the deck gun. It's even more
hilarious when you finish off BB's or CV's with the thing.