Part of the problem may be the Submerged drought settings?
Those are in the sim file.
Crash depth may also play a part at times.
Why does a surface unit need a crash depth of 300 meters?
So you can follow it down I guess.
But any ship sinking is rendered until it hits the crash depth.
I've followed them down to the vanishing point.
Sink any ship in shallow waters and you can watch them hit bottom.
Go beyound render range they will vanish.
But if you don't go beyound render range?
They will stay on the bottom because they have not passed crash depth.