In my game, the sea action is crazy.. Macedon, Ptolemies, Cartghaginians, Hellenes, and me as Rome, have all built larger fleets from 250-ish onward to the present day (190 ish). Domination of the sea is a major goal for each of these powers, and there are several naval engagements each turn in the crowded sea-lanes. The Macedonians are even building the "Huge" ships in their great naval ports now, seeking mastery of the middle sea.

of course, im playing 8.x on the BI exe so that may have something to do with it.