We weren't looking forward to scrubbing off the tropical growth we knew covered Seraffyn's bottom when we reached Costa Rica many years ago. Then there was the task of sanding the bottom ready for the new paint - that presented a dusty, messy job. But the thrifty Costa Ricans showed us a trick we have used many times since. They had a square washbasin full of sand - yes, regular beach sand, and a long handled brush waiting as soon as the boat came out of the water. Dip the brush in the sand and scrub using a hose (or if you are on a tidal grid, scrub the bottom as the tide goes out so the paint stays wet). With only an hours work the bottom was clean, rough sanded and we only had to do a bit of spot sanding to be ready for fresh bottom paint.
Mike Kris, a cruiser we originally met in Mexico then rendezvoused with throughout the Pacific, showed us another way to make shipyard time less messy. He finds a quiet bay with clear water to anchor in a day or two before haulout time, then dives and scrubs the boats bottom, using a heavy duty scouring pad. Cuts down on cost by saving sandpaper and shortening the time in the shipyard too.