Guys have a read of the after action report of the surgeon from HMAS Sydney after he battle with SMS Emden, Sydney mounted 6" (15cm) guns and Emden 4.1" (10.4cm). This will give an idea of the types of injuries recieved as a result of HE and AP shells going off in close proximity to humans.

http://www.ku.edu/carrie/specoll/med...arby/darby.htm

why dont you just add ammo or fuel as cargo to every top level item.

Obviously you would want to up the hit points on some things so you don't always get the rolling damage that spreads through the ship thus making it look too easy,

You also may need to add special effects such as smoke to certain areas below sea level etc so at least you see things as the ships sinks by torps bacause if upper level hp is too high, you miss some special effects in game.

I do not think anyone has explored this yet so may take a quick look myself.

I do not reccomend anyone just rushing into it as there are always side effects to identify and deal with.