They even use a cut down version of the main guns to replicate torpedo's.
When you start out you start as a merchant (unarmed) and try and avoid being sunk (good luck!
) Then you work your way throught destoryers, cruiser and then battleships. I believe they even have aircraft carriers! (don't know if their armed or not) Diffrent sized guns get different size ball bearings, so damage is to scale ( no destroyer outgunning a battleship!)
They even do hypothethical battles with ships that were planned but never built. The least popular job is the guy who has to go fetch the sunken ships!!!