Prop slip occurs when a prop fails to achieve its power potential. This is due to resistance from the water that prop is working to propel the boat through. As the prop endures the resistance, it tends to slide back and does not go the actual full distance in that one revolution.

What causes excessive prop slip?

Propeller slip is affected: by factors related to the engine, the boat and the boat set-up: the type of the hull and its condition, the weight and the aerodynamic design of the boat, the design of the engine’s lower unit, the mounting height of the engine, the loads as well as the design of the propeller itself.

How do you know if your prop is slipping?

To tell if your hub has spun, mark a line on the back of the prop hub with lipstick. You can also score your mark using a file. With the mark in place over the inner and outer hub, it’s a simple matter to pull the prop and see if the mark has broken in two. If it has, you have spun a hub.