I swear by my Costas... Theyre 'spensive, but theres no way to describe how awesome the lenses are... I have a few pairs of Brine blue/green mirror 580G's, and they have yet to see a scratch on the lens... The 400's would most likely suit you just find for sailing, while being cheaper too! I have 580's for fishing
Can't go wrong with Costas. I'd also recommend Smith's. I got a pair as a gift (no idea what model) and they're fantastic for being on the water. Not sure how much (a simple search will figure that out), but I'm sure they're not cheap either.
Careful with the Kaenons. My friend and I both had a pair. The outside coating can get all puckered and cause distortions. Really hard to describe, but for that kind of money it's worth asking about. Still, they were some of the best polarized glasses I'd owned. I have Revos now and love them.