Ramming speed.

Can’t believe none of you listed the RMS Queen Mary’s run in (so to speak) with the light cruiser HMS Curacoa…

@Red:

The last boats that I would think of making a ramming attack in the WWII era would be capital ships, particularly undamaged capital ships.  Big ships were stand off weapons (aircraft carriers and battleships.)  Unless there is a long/mid range combat phase followed by a short range naval combat phase I don’t see how the attack roll would work conceptually.

An excellent point.  Using big ships as rams rather than as long-range weapon platforms would be roughly in the same league (though slightly more credible) than bringing them alongside an enemy ship so that the crew – armed with pistols and cutlasses, if their captain is a traditionalist – could board it.  The British captain who came closest to carrying on this tradition during WWII was (as I recall) Captain Vian of HMS Cossack (a destroyer), who led a boarding party over to the German supply ship Altmark and freed its POWs with the dashing remark (addressed towards the ship’s holds), “Any British down there?  Well, come on up – the Navy’s here!”