My limited experience has taught me this:

A boat can be done with a DA but expect to shred some pads and use more product that a car/truck. Moving forward I would suggest this as a bulletproof list, again my 2 cents.

- Rotary Polisher
- wool pads
- finishing/polish pad for LSP
- APC of some sort
- LSP based on what you need/customer wants

I did a boat using 3M compounds and had good results. 845 makes a great LSP although they make one thats marine specific. The marina staff commented to my friend how nice the boat looked for a 12 year old machine. I spent lots of hours on it proving it can be done with a DA but do yourself a favor. ROTARY!