Prop Wash – Big Metal Screw edition

This week I will be covering prop material and blade count effects on propellers, screw, hélice. Whatever you feel like calling it. The material of your prop has a greater effect than most hobby boaters realize. Plastic Props are cheaper to make and work fairly good so most boats come with that material. Metal is much stiffer giving you a crisper feel and and better throttle response. Plus a metal prop stays sharper and smoother longer, and is much more resistant to shearing off a blade. I like plastic props for fun on water I know, and metal for performance and ponds with debris.

Blade count is more for balance, efficiency, and surfacing “running a prop partially out of water”. The fewer blades on a prop the more efficient it should be but harder to balance and less resistant to surfacing power loss. Higher blade counts are less efficient, balance easier and are more resistant to surfacing power loss do to more blades in the water. Three bladed props are common due to their efficient nature and ease of balance “think jack of all trades”.

For all the ‘but I got an outboard crowd’, any boat that steers by turning a lower unit with the prop, a general rule will gain steering with more blades. More blades = More surface at a given angle.

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