How To Remove an Inboard Boat Propeller

How to get a tough prop off the shaft

There are numerous ways to remove a propeller, including harmonic knockers, screw-type pullers and more. Sometimes a smoke wrench, aka a torch, applied to the hub is needed to make a stuck prop yield.Capt. Vincent Daniello

Removing an inboard-powered boat’s propeller is a straightforward boating DIY task. Sometimes, though, a prop will cling to its shaft with the tenacity of a barnacle to a piling. The following tips may prove helpful to all those who need to remove a propeller.

Leave the Nut On
With a block of wood preventing the prop from spinning, remove the cotter pin and loosen both nuts. Remove the half-height nut completely and leave the full-height nut on the tail of the shaft, with all of its threads engaged. Since there's usually at least some force required in removing a prop, this prevents the prop from falling and becoming damaged (or landing on your head, hands or feet) as it pops loose.

Try a Grab Grasp the propeller firmly by the root of two blades. Give an even pull. If it slides off the taper, sing praises to the deity of your choice. Watch out for the shaft key, which often falls out at this point. Box up the old prop and send it off for reconditioning, then install the new prop. Prop removal is rarely this easy, so check out some more removal tips.

Prop Knocker
You may need to turn the rudder slightly to provide clearance. Remove the nut and screw the prop knocker, aka harmonic puller, onto the shaft. Hand-tighten, then rap — don't bang — on the prop knocker four or five times with a hammer. (Oh yeah, don't miss and hit the prop.) Hopefully, the vibration loosened the prop from the shaft taper. Grasp the prop, remove the knocker, and remove the prop. If several knocking attempts fail, move on to another method.

Prop Puller
The Algonac prop puller ( is probably the most common style of prop puller in service shops, but there are many variations on the theme. All use the simple machine known as the inclined plane — here in the form of screw threads — to exert inexorable force in a controlled manner between the forward side of the prop hub and the tail end of the prop shaft. The prop will jump loose, so do have the big nut threaded onto the end of the shaft. Watch for that pesky key!