what spoonfeeder is quoting is just a paint job. No prep. sounds like your boat may need to be completely stripped, prepped and painted. if you are keeping in the water all season I would suggest barrier coat and then bottom paint. I re-did my boat last year. 278 Baha. Paid about $500 for someone to media blast the bottom a prep. I had about $500 in paint and barrier coat. Put on 3 coats of barrier coat and 2 coats of bottom paint myself. very time consuming process. to have it all done by a reputable place runs about $100 a foot.