Try this ES. Get pops to run the boat down the lake while you're layin on the back deck. At wide open throttle stick yo arm in the water as deep as you can reach. Feel the amount of force it puts on yo arm. Then pull yo arm up about an inch at a time and see if the resistance slowly goes away. It's the same principle as yo motor.

You may wanna consider installin a whale tail on it. I had to on mine. It will keep the prop from blowin out and keep the boat on plane. Ifn you do get one, get the aluminum one, not the thick plastic one.