I had a big heavy old Wildcat grinder that I've used for years with a variable AC transformer. Weighed a ton so I spend 30 bucks at Harbor Freight for a variable speed 7" polisher. It worked fine. A couple of things:

I used a 20 foot long piece of 5/16" bungy cord (also from Harbor Freight) attached to a halyard and to the polisher. Hoist the halyard until the polisher "hovers" at mid-hull. That eliminated about 80% of the effort. It also gathered a crowd at the boatyard saying things like "Wow, that's cool. Can I borrow it when you are done?" I accepted several beer bribes over the course of the week. I can be bought.

The polisher came with a hook an loop backing pad and some crappy fake wool, terry cloth and foam pads. In the past I've used real wool pads that tied on with a drawstring. I went to my local professional quality True Value hardware where I had bought them in the past. The guy says "We don't have them anymore but we have some thing better" I was not happy but bought his recommended pad instead. It was a hook and loop affair that looked like a frisbee with dreadlocks. The fibers were real wool yarn and woven into the backing pad. It worked great, better than the drawstring version. After the polish job was complete it still looked good as new. For the polish I used Collinite cleaner but have also used other polish compounds from McGuires and our local professional auto paint supply hours. I don't claim to have a favorite.