Bottom Job / Barrier Coat
Peel-Away seems to be the #1 choice. Or it''s Lowes/Home Depot equivalent. Second choice is probably blasting with sand or beads. A lot depends upon what the marina allows.
On my 37-footer I used paint scrapers, a wide one and a narrow one. Filed off the corners to prevent gouges. It took a long time but was very cheap with no dust or chemicals. I used 100 grit to finish down to white gelcoat.
There were about fifty pencil eraser size blisters that I dremeled and filled. Then five coats of Interlux 2000E barrier coat. I use a modified-epoxy bottom paint, Trinidad SR. I like the hard, smooth, fast finish compared to ablatives. I have easily gotten two seasons, could probably go three(in fresh water).