While nearly everyone has an opinion regarding how to do it, no one likes bottom work. Having survived countless cleanings on my boat and others while working in yards, some opinions follow:
1. Never, ever haul a boat with growth and allow it to dry. Pressure wash immediately after hauling. The vast majority of growth will blow off or can be scraped easily with a putty knife. Then you can haul it wherever you like.
2. If the bottom dries (i.e, much more than an hour), you pretty much have to sand it down.
3. After the boat dries, work with a tarp under the boat to catch debris. That is, when prepping for new paint or when removing all the old paint.
4. Sanding/scraping/peeling to bare gelcoat is a real job and one that many people leave to a yard. If you chose to take this route, there are many threads on SailNet discussing options and techniques. IMO, it's much more work that buffing a hull, in part because you're working overhead. We did our hull in 2009. Photos follow Victoria Bottom Stripping & Fairing
5. Bottom paint is generally applied yearly. An exception is ablative paint that may not have to be reapplied depending on thickness of the base and the type. Not all ablative paints are multi-year and can not be relaunched. Micron CSC and Pettit Hydrocoat are examples of multi season, ablative paints.
6. Sanding is required prior to overcoating. I can sand our 38' hull in 2 hours using a 6" random orbit sander w/ Shop-n-vac.