Power wash the hull, hit it with some 150 grit sand paper and then roll the antifoul paint on with a 3/8 nap roller. It will take you a half a day and cost you $100 bucks tops.
I wish it were that easy and inexpensive. It has never been like that for me. I can’t count how many times I’ve done anti fouling paint jobs on boats, and it was always more work than that to sand and put on two+ coats.
First, there’s the time and maybe money to put the boat up on stands. That alone can take a couple of hours at the start and finish. And you have to have boat stands, or at least some DIY substitute.
For sanding the old paint smooth and to get the new paint to adhere well, you’ll need to rig up a high quality vacuum to the sander, and wear a really good particle respirator, if you respect your health and the environment. 80 grit is what you usually use. Follow directions for how long to wait between the first and second coat. Usually you want two coats, with a third coat at the waterline and on the leadind edges of the keel and rudder. It’s at least three hours at 90 degrees for many paints.
I’ve done bottom paint on my Catalina 27s, Potter 19s, J/70s, Corsairs, and helped with lots of friends boats. I’ve paid to have it done too. Paying a professional to do it is a lot easier on my 68 year old back and knees but tougher on the wallet.
My advice is to read and follow instructions on the can to the letter, if you do it yourself. There are different kinds of paints, all with different requirements. Research to be sure the new paint is compatible with the old. For example, you usually cant put solvent based paint over water based paint without extra procedures.
Research the best paint for your local conditions: fresh water, brackish, salt. Year round vs 5 month season. Keep the boat in a wet slip vs sometimes on a trailer.
Judy B