[CapnScurvy]

So it sinks when the waves go over it? Do waves cause damage when hitting upper decks? I imagine only to ships and not subs..

I suppose GFO players won't see many J class destroyers patrolling around, they might even find a few unescorted convoys if the wind is up

I believe that's right. You probably would never know a J Class was in the game if it sinks on its own.

I've seen something like this due to the "Center of Gravity" with other modded ships as well. Moving the "displacement value" requires you to also change the ships "center of gravity value". If you don't, the ship may actually roll over in mid to heavy seas due to the change in balance. The other day I had a test mission with some RSRDC v550 ships and noticed a couple of the Japanese destroyers were rocking heavily left to right. I had the wind blowing about 10 miles an hour. A couple of the added DD's (I forget which ones were doing it) were rolling so heavily I wondered if they would capsize before I finished my testing of AI sensor capabilities. I don't know if I would have let the game run for an extended period of time, would they get worse and eventually sink or not?

I once set the "center of gravity" on the Fuso to a point that when I started the test mission and took a look at it, the ship was rolling so fast (like an alligator in it's death grip) that it eventually spiraled itself straight to the bottom after about a minute.

I don't know how the game addresses the factors of ship damage to the point of sinking due to water intake. I know it does for surface ships.