First of all, if you have the money, consider seriously getting a good boat yard to plane your hull and rebuild it. If you can't afford that, decide if you want to go through the pain of doing the following job yourself, or if you want to hire a boatyard. After completing the months of work, and having experienced and lived through the pain and mental aguish (one of the hardest battles with staying patient that I can remember) I'm glad I did it on my own. There's *no way* a boat yard would have taken the care that I did. Now, I know it was done right. The Job... You'll become quite intimate with your sander. I used a 5" Dewal Orbital sander hooked up to a small Shop Vac with a long vaccuume hose to allow for easy movement. Clean filter often (2x/4-6 hours of sanding...all I could stand in one day), and change regularly (1x/12-18 hours of sanding). If you can find a 9" orbital sander that hooks up to a vac hose, I'd give that a try. Might save a bunch of time, but also might be too much to really controll (don't want to go sanding flat spots or holes where you don't already have them.) Start at one end and do workable sections (ones that don't drive you insane) at a time. First pass sand off a majority of the bottom paint until you have just a shade of bottom paint left. Then, before starting a new section, go back and do a 'clean up' sand to nice while gell coat (Don't take off more than you have to!). 80 grit worked best for me (3-4 coats of VC17). I found myself sanding and digging out blisters at the same time. In other words, I didn't sand off the bottom paint on the entire hull and *then* go back and attack blisters, I did them at the same time...section by section. What I found.....were blisters that were obvious, and then also small (push-pin sized) spots of bottom paint that remained. The spots of bottom paint were actually blisters, now concave (ever so slightly) from lack of water or disolved resins. Sanding by hand is the only way to uncover these hidden parasites. To the obvious blisters.....I gave them a left upper cut with a nice sharp 1" chisel. Stuck a corner into the middle of the blister (you could hear them cry as you struck the first blow), watched it flex and penetrate, and then dug into the blister with a circular motion digging out the results of hydrolysis. Death to you Mr. "stop eating my boat!" Blister. Once the main blister was out, I put the edge of the chisel along the edges to see if there were some "runners" where layers of gel coat was coming off. I did have some where it seemed just the outer laminate was being effected. These (4 or 5) were disheartening. Instead of a quarter-sized or smaller blister, i'd have a shallow 4x6" area that proved difficult to epoxy and fare later in the process. Basically, ya dig and strip until you get good meat. It wasn't too difficult to figure out where that line was. Pretty obvious. To the spots of bottom paint..... I poked them with the corner of my trusty chisel gently to see if there was any flex. If they flexed, I dug them out to good meat. If they didn't flex, I tapped around the area to see if it sounded out ok. If it did, I let it be and just sanded off the dot of bottom paint. Figred if it was still solid, why mess with it. Barrier coat would stop any further effect. So, that's where I drew the line. Flex and sounding. If one was compromised, I let my chisel off his leash and go to dinner. Once the blister was staggered by the chisel, I gave it a final uppercut with the sander. Gently placed the edge of the sander into the middle of the blister, and sanded down to solid glass. What was left was an oval cavity. We found this shape to be very easy to fill with epoxy, and subsiquent sanding of the hardned epoxy was made easier too. The attached photo.....shows the hull now in a solid state (you'll notice I was also repairing some corrosion on the keel and a small crack on the port side of the rudder). Naked solid white gel coat with brown cavities where hydrolysis once had been playing its evil game. The boat is now void of cancer. Everything is solid. She's starting to heal. Some Tips.... Wear ear protection and a mask. The sander does a good job keeping dust out of your eyes, but some eye protection is a good idea too. I used a pair that look like sunglasses. They were the only ones that didn't fog (tried chemestry type, swim goggles, full wrap arounds...). Buy a bunch of masks. Wear a hat or full body suit with hood. I simply had the same clothes that I changed in and out of there in the yard. Wrap everything (shop vac, hose, sander, clothes) in plastic garbage bags before transport. The dust is nasty. Wear work gloves and every now and then pass the sander over the palm of one of your gloves to remove any dust from the sanding disc. Most important tip..... Do your sanding in the winter. I'd rather sand with 3 layers on, than in warm energy sucking temperatures. I had several days of sanding in the low teens and was perfectly comfortable with layers, a wool hat, and some good yet expendable mittens. Next episode..... Filling the voids with my very good friend, Mr. Epoxy. Kevin in VT