Prop ... low pressure, Cup, and 3 or 4 blades.

[Lake X Kid]

https://youtu.be/D686Gy7vkHc

[Lake X Kid]

In the previous Propeller Physics video, the general rule is that a 3 blade will be a few miles faster than a 4 blade's top end.
Whereas the 4 blades will accelerate the boat faster than the 3-blade prop.

[hellbents-10]

When the whole prop is in the water!

[David]

When the whole prop is in the water!

Yup. In the old submerged days, there were 2 blade props.