Painting my Fisherman 18

[tsubaki]

Alright you're set on spraying the bottom and at least the sides.
In order to spray the entire thing at once and not removing anything on the boat, this is all I got:
Do you have the room to build a gantry out of 6x6's?
4-6x6's in the ground 3' each, 10' apart and as long as the boat is where the bow/stern eyes are. Bolted together with 2x6's and 1/2" bolts. The 2x6's are to keep the poles from pulling together under the weight of the boat. Attaching 4 come-alongs at these same locations and lifting the boat off the trailer.
My father and I did a similar thing with another boat but had 2 Sweetgum trees about 20' apart.
Also, please do have some blocking for safety purposes and when you're not present.