Two springs after I bought Banshee, I decided to strip the bottom down to bare. We looked for someone to come in and blast it but I ended up deciding to do the job myself - never again. The boat was 35 years old at the time and had at least 20 layers of bottom paint on it. It took five successive applications of paint stripper gel to get down to where the some hull was showing through.
Even with some help from my sons and an occasional "Tom Sawyered" bystander, the process took 5 successive weekends to complete. My advice to anyone now is to find someone who will soda-blast and pay for it. Also never, ever, use anything but ablative paint. We ended up with 18 kitty litter boxes full of the resulting paint/stripper goo, which had to be disposed of.