one word : useless... no, two... Completly useless. But if you're filthy rich and wanna loose some treasury, build a invincible navy and go hunt the pirates in the baltic sea... you'll have plenty of stacks of 10 + ships to destroy! that's the only use of your ships : draining your coffer (well, appart of shipping your troops and preventing an eventual (and VERY eventual) naval invasion by the AI)

Well, of corse, that's my humble opinion!

cheers!