I haven't tried it lately, but I have experienced similar. I never could decide if it was the explosion of the sub's ordnance, or the ship's explosions, but I suspect it is the shell's "proximity" effect. I do not remember how much damage we took at the time, but it was rather considerable... we may well have sunk, but I do not recall... Seems to me that the deck crew on my boat was killed by the "blast" also...
