Above and Below the waterline

brush, can or spray pant?

Lighter color 1stest, darker colors lastest.  I'd prime the whole thing, then shoot the green w/out masking, up into where the black will be.  After the green is thoroughly dry, mask the parting line with a good quality masking tape.  Go with a small width ( about 1/8") if you have a bunch of compound curve to deal with,  then use more tape/paper to shield the rest of the paint.

Make sure you use a good quality, low tack masking tape like Tamiya or 3M blue painter's tape.  If you have REALLY deep curves to worry about, use something like master mask or micro mask liquid masking a CAREFULLY cut the linework needed.

Reid

I do like Reid said, except I use a coat of Future over the 1st color.  This helps protect it from peeling when you mask it off to do the 2nd color.

--chris

Masking the deck can be a pain.  BTW, I paint hull before I add any superstructure above the deck, to aid masking problem.  Do the best you can with desk masking.  If you are airbrushing, you can often put on the paint with the brush below deck level, angled upward, so the deck masking can be less than perfect.  Depends a bit on how the deck/hull interface looks.  I sometimes even paint the hull before I add the deck.

I paint from the bottom up; so I do the below-waterline hull even if it's a darker paint than the above-waterline paint. Two reasons are that I find it much easier to mask (see my article on airbrushing ships here) in that order, and also, because the above-waterline is painted later, any paint ridge is harder to see since you are looking down on it. For things like dazzle schemes, 99% of the time I will go lightest to darkest.

The other advantage to this is that *if* you have a secure mount to your stand, it gives you a good work hand-hold you can use without having to handle the hull and get fingerprints on. I usually fill the bottom quarter inch of hull with resin, though, to make sure I've got a good grip that won't split the hull seam, etc.