I just sanded mine. *I did it with a 25 pack of 60 grit discs for a random orbit sander. *A circular sander or dual action would have probably been faster.
I've been grinding fiberglass recently, that is a messy job. *I found a bit of a problem while doing some fuel tank work. *There was a 1/2" thick film of fiberglass dust along the bottom of my boat before I vacuumed it. *It's really miserable rolling around in the bilge with fiberglass dust everywhere. *Nowhere near as bad as on your back with bottom paint dust, though. *While doing the bottom paint, my goggles would fog up every 3 minutes and really did nothing to keep the dust out of my eyes. *It was terrible.
I am doing fiberglass becase a stringer was cut to pass the fuel fill hose through. *It was also cut deeper than it needed to be. *The result was the stringer broke, probably while trying to do 12-15 knots in 8-10ft swells at 8 seconds with 3-5 foot wind waves. *I didn't know it was broken until I pulled the fuel tank. *I was able to cut the damaged section out, scarf in a new section, and lay 2 layers of laminate in a day. *I was going to finish today, but it is 90+ degrees right now and I had the wrong hardener. *My resin pots were setting hard in 3 minutes. *The day before it was 60 degrees and I was getting 15-20 minutes before the pot would even start to gel, 8 hours till solid.
There is very good reason I do all of my sanding and such. *I did this in a day for $16 worth of wood and $150 worth of resin and glass. *I can't imagine how long it would have taken for a yard to do and what the cost would be. The bottom paint job costs $11 for sanding discs, $65 for a sander, $60 for primer, $12 for safety goggles, $24 for dust masks, and $180 for paint.