If you are wondering why our engines rotate counterclockwise (when viewed looking at the output shaft) - It is because model boat racing engines started as modified model aircraft engines.
Back in the day, these model aircraft engines were started by hand, by manually "flipping" the prop. There were no electric starters at the time. Since most people are right handed, the model engines were made to be manually started most easily by a right handed person. So that's why our crankshafts rotate in the direction that they do.
The direction of the crank rotation affects the forces of prop walk and torque on the hull and driveline, causing most boats, especially hydros, to want to right on their own. And that's why current model boat racers run their races clockwise.
With the advent of the brushless fast electric boats, you'd think they'd eventually convert to a "proper" counter clockwise course, so our models would look more like the rest of the world's full size racers...
[Left handed boat props would need to be developed, of course.]
