Sander With Suction
You ask what's important. Answer: Sander that has suction capabilities. I also started with a 1/4 sheet DeWalt but you need special capabilities for real production.For bottom paint you don't want that dust hanging around. You want it contained. [answer to #5 is YES!] A random orbital sander with suction capabilities with a hose (most have adapters) connected to a shop vac will do a clean job sanding bottom paint. The other advantage of the vaccum is it helps to keep the sand paper from clogging up.Personally, I use a Bosch random orbital, 5-inch, that I got about 10 years ago, or so. I use a "soft" backing pad with Velcro [answer to #2 is hook & loop] and it has 8 holes. I've done the boat bottom every year with this setup, until last year when I skipped, and it's worked fine. The backing pad was replaced the last time because the hook-and-loop wasn't sticking well anymore at a cost of under $20 from Tool Town in Seattle.I use 60 grit paper which I buy in bulk, 25 pk., and use about 4 sheets on a 35 foot boat with Petit Trinidad. The other "what's important" item is to hire someone from Labor Ready at $15/hr to run the sander! Sanding time is 4 hours and I use him for another 4 hours waxing the hull while I do the painting and the other less labor intensive jobs.The random orbital with suction helps to keep the paper from clogging on varnish too. The life expectancy of the sandpaper will really increase over your palm sander - at least it did for me. Plus you don't have the problem of ripping the paper to size and trying to "feed" the paper under the clamps.Shop Vac: use a drywall bag and not a regular paper bag to keep the copper out of the motor.Connecting Hose between the sander and the shop vac - keep emptied of dust. Because the bottom paint is heavy and because the sander and the shop vac is above ground level there is a tendency for the heavy bottom paint dust to settle out in the hose so periodically, starting at the sander, raise the hose up and allow the dust to flow into the shop vac - but do it gently so as not do dump it in the shop vac all at one time because it can't handle it.Coveralls: Use Tyvek with built-in hood. http://www.tyvekcoveralls.com/coveralls.htmlPolishing and Waxing: Bought a Electronic Sander-Polisher, Makita 9227C - 7", specifically for waxing. Variable speed (0-3,000 RPM) with pre-set maximum speed dial; ideal for ultra slow polishing. Also uses a hook and loop pad; wool for wax. http://www.makitatools.com/tools_Item_View.asp?id=257Answer to #6: both of these tools have good comfortable handles for long hours of use.Answer to #7: This particular Makita has a good following among professionals that wax boats. It was somewhere around $200, more or less. This particular Bosch is an old model now and I don't remember what the speed details were. It wasn't terribly expensive. Use ONLY ONE tool on bottom paint because it will turn the color of the paint. I use the same extension cords and work boots year after year. In fact, I have a Sterlite plastic box with all bottom-paint supplies (except the paint) and haul-out related tools along with computer haul-out check lists, one for work items and the other for the box inventory to ensure I have everything.Oh, and the shop vac bag - make sure the weight of the paint dust (you know how heavy a gallon of bottom paint is) doesn't pull the bag off what it's attached to otherwise you'll have a real mess. Check it from time to time and empty early if necessary. The cost of a new bag is peanuts.