What Primer

I use krylon primer from Lowes (or whatever is cheapest) then I decant it, and spray it through my airbrush.  It works very well on resin as well as styrene.

Chris

I prefer Tamiya's spray can primer.  You can get in gray or white.  I like the gray the best.  It is a little expensive though.  If I can't get Tamiya's primer, I use Testors Model Master enamel primer which is gray also.

-Jesse

I'd just use some Tamiya Flat Gray or White...why do you need a primer at all? The boat will be a dark gray or black right...so even color coverage isn't going to be an issue. If you are worried about your seams, then just lightly mist them with either of the two colors I mentioned above.