Three Ways To Untangle A Boat Propeller

By Tom Neale

If your engine stops suddenly, you may have run over a line. Here are three ways to get out of it.

Propeller tangled in crab potDon't let an unexpected encounter with a crab pot ruin your day. (Photo: Scott Croft)

I don't know which I hate more: getting a line wrapped around my prop or trying to figure out what to say to the crabber or lobsterman when he comes up alongside. But you may be able to save the day before you're busted. There are three ways to untangle your prop and get underway again. Whichever one you use, always stop the engine first and take the key out of the ignition.

The Wet Way

Under ideal conditions, including calm seas, no wakes, clear warm water, and having someone aboard who's fit enough and skilled enough to do it, someone can dive under the boat and cut the mess loose. (Keep a mask and flippers aboard for this purpose. Never do this alone.) If the line is nylon or polypropylene and if your running gear continued spinning after the entanglement, some of the line may have "melted" together, requiring it be cut free.

A knife with sharp serrated blade works best for this. If you dive, check the cutless bearing and any shaft seal to be sure none of the line worked inside it; this could cut the sealing material. But in less-than-ideal conditions, try clearing the line from the boat without getting into the water.

The Short-Reach Option

If you have an outboard or sterndrive, tilt the engine or drive up and try to clear the line directly if someone else is aboard to watch. If you can't reach the line from the boat, try untangling it with a boat hook. If that doesn't do the trick, try taping a sharp knife to the boat hook to get enough reach to cut the line. Any line that's left could do damage, so clear all line before restarting the engine.

The Inboard Option

If you have an inboard engine and can't get into the water, start by finding the free end of the line. Sometimes this will be on the surface with a float on it, and sometimes you'll see it trailing off underwater. Fish it out with a boat hook, and post a person on the stern to hold and keep tension on it. Be sure the ignition is off and that the engine can't start. Have someone go below and hand-turn the shaft of the entrapped prop. This may or may not be easy, but usually it can be done.

The person on the stern should tell the person turning the prop whether the line is getting shorter or longer. If it's getting shorter, turn the shaft in the opposite direction as the person above deck pulls in the line. Hopefully, you'll unwind it and soon be free.

If the line won't completely unwind but seems to reverse direction as the shaft is turned, experiment while keeping tension on the line, reversing the turn of the shaft. Sometimes turning the shaft one way, then the other, is necessary to free a kink. Gauge your overall progress by noting whether the line is shortening or lengthening. If you can safely reach the prop with your boat hook, you may be able to "fiddle" with it from the deck to free up snags or kinks.

If that doesn't work, a knife attached to the boat hook should allow you to cut away the majority of the line. You may be able to completely clear it from your gear or at least from whatever it's attached to at the bottom of the sea, so that you're able to get back to the dock. However, if you run the engine to get home while there's line still on your prop or shaft, you risk having it cut into the cutless bearing or shaft seal. Judge if that's a risk you're willing to take or whether it's preferable to call for a tow. 

— Published: April/May 2018


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