I have not been able to find much technical information on the engine rules for this class. They run transom mounted water pickups so the motor is mounted very high. They modify the skeg. Making it larger so the boat will turn. I have seen videos of racers porting the smaller hp engines, but not the 30 hp Yamaha 3 cylinder.
In Mod C in the states. The Yamaha was had special custom engine sleeves and pistons to increase the displacement to 35 cubic inch. That was the maximum displacement under “C” class. Ron Hill had some NOS Mod C Yamaha pistons and I believe they were shipped overseas.
Their boats have a lot of speed....nice engine sound....boats produce almost no wake.
https://www.youtube.com/watch?v=NoMLpe3l2bQ
