My friend and I recently purchased a 1970 slickcraft. The bottom of
the boat has this nasty blueish green antifouling paint on it (a
couple of layers I think). In the spring we are looking to repaint it.
I ordered a couple of cans of black antifouling paint from ebay.

I'm looking for some advice on how to do it...

does the old stuff have to be sanded off?

whats the best way to do it with it on the trailer?
we were thinking about sliding it back on the trailer alittle,
painting what we could then sliding it forward to get the rest.

does it have to be brushed on, or can it be sprayed?

we were also thinking about repainting the outdrive, does that have to
be antifouling paint as well?