My last boat was a 22' venture. When it came to painting topsides & bottom, I
would jack the stern up about 1' off trailer & support with a pyrimid made of
timbers & 4x4s , making contact on both port & starboard directly under
transom. Next I would take a 12' (6x6), center it under bow end & jack &
support the ends of the 6x6 until the bottom of the 6x6 cleared the trailer
fenders. Pull the trailer out & add at least ( 4) 2x4x8 s from ground to just
under rubrail for extra stability.