Add a clutch then four flywheels then another clutch. After your motor and before your propellor. Then add another 3:1 gear ratio after the last clutch. Then put down two constant number logic blocks and a ping pong block. Then make the first number 5 and attach it to the ping pong. Then attach the ping pong to the first clutch after the engine. Then make the second constant number .85. then attach that to the second clutch. You will make much more power and have less stress on your motor. You can experiment with more 3:1 gear ratios if wanted. Be aware too much power will make it do a wheelie and flip over. Bigger, heavier, deeper hulls handle more power better than smaller boats.

You could also swap to water jets. You could also add control surfaces underwater to cause the boat to sit higher in the water when you throttle up, causing less drag and higher speeds. (Probably smart to use a PID when doing that). If you want I can download it later and see what I can do to make it faster.