The advantage of dry sanding first is that you can identify any drips or rough spots that need extra attention. I use 220 Sterate no load paper (the grey stuff sold at boating stores) then I switch to wet sanding for a final going over. You can add soap to your water for a lubricant. This is what body shops do.

As far as the comments that it's not furniture. Below the water line I agree. My boats take quite a beating. but from the gunnels up, I lke to keep them looking good.