This one is fun too, it's a mid 70 mph boat, 13 hp, spins the prop 40,000 rpm's... and it's only 4' long! Radio controlled. The motor is electric, it runs on 52 volts 200 amps! I have trouble keeping the wires from melting if I run hard for over 2 minutes. LiPo batteries are awesome. You can weld with a big rod on 200 amps.... If you look close you can see the prop above the surface at 40K and the wake of the boat launching out of a turn. Here's one of the props I built for it. Its stainless - 2" diameter, .020 thick and very sharp! That board it's setting on is 3" wide...lol notice the nail head indention on the right? If you hit the throttle hard at 50 mph, you can blow the boat right over with power. I mean think about it, 13 hp and only 6 pounds! 2HP / pound. How would you like to have a 2500 pound mustang with 5,000 HP?