Instead of trying to figure out ratios on drill batteries and the like-pause- now at 24 oz. 1 1/2 lb. ( quote- boat ) get a Monster maxx wild motor and then get a 11.1 lipo in the 3000mah range and use a 632 prop and go have a blast. Keep the boat light and use a brushed 45 amp esc, make a viceo. No i'm not crazy. I have 2 Mutineers with Speed Secret motors at $22.00 from tower at 40,000 rpm and a 632 prop on 6 cells and fly. They are heavier than your 1 1/2 lb. boat.