http://agathe.gr/democracy/the_athenian_navy.html
The Athenian Navy With thousands of kilometers of coastline and hundreds of islands, the Greek world was likely to be dominated only by a naval power. A generation after the establishment of democracy ... With the three tiers of rowers that give the trireme its name, the ship acted as an oar-powered battering ram manned by highly trained and disciplined rowers.