Re: power tool voltage for cruising: 12V or 18.5V or 110V AC?
If you have the room aboard the boat, I'd consider one of the 18 volt drill/sawzall kits. They're around $120 when on sale, that would give you 2 batteries. If you have an inverter on board, you could charge the batteries when motoring. Having a sawzall with some metal cutting blades on board could be pretty handy if mishaps with your standing rigging/mast should ever occur.