Landonshaw: you're in Grenada
, hire a guy in the yard for the job as you will make him happy, keep yourself healthy and it doesn't cost much compared to the price
of the paint.
Yes, pressure wash thoroughly, stay with the boat and check they do it right. If at all possible, have them move the slings to pressure wash those spots too or scrub it immediately after they put your boat on it's stands. If that stuff dries out it's much harder.
If your paint is of the ablative type and the same as you already have, you can scrub with water
and scotch-pad instead: no dust (I think it's better than sanding). After scrubbing/sanding, wash/rinse with just water
and let it dry real good. Check for "blister like things" (can only see them after sanding/scrubbing and drying). These are probably just in/under the paint but remove them anyway. Put some layers of paint on these spots with a small brush (to fair them out) before painting the whole boat.
Painting: mix, mix and mix the paint again, use the paddle thinghy on your electric
drill for that. Next, pour the complete can over into another can/container and scrape all the thick stuff out of the original can into the other one. Mix, mix and mix again. Did I mention to mix it well?
After the 2 1/2 layers are on (indeed the 3rd layer also on the leading edges of bow, keel
and rudder plus the surface above and behind the prop), let it dry for at least 5 days before launching. The paint will last much longer that way. We use Islands 44 plus and it works well for 3 years when done this way.