Epifanes two part urethane

[bigeasy1]

I'll only be spraying the hull above the waterline with the urethane.The rest is bottm painted.
I've sprayed urethanes before and had good luck with the finish.
I have a buddy who sells the Epifanes line of stuff,so it's easily availiable to me,and i can save a few bucks.I sprayed the outdrive with it,and even though i wasn't fussy it looks very good,and seems extremely durable.

Thanks for tips guys,i'll give signature a call,and pick his brain.
I would like to know just for my own interest,what the difference between them are.Some are described as linear urethanes,and others as saturated aliphatic catalyzed urethanes.***HUH?