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  • Shaft propeller removal and cleaning.


    Today my boat was lifted out, so the first job I like to do is remove the prop, inspect it and give it a good clean. 
    A well polished prop will gain a fast fisher a knot or two, the same as a stainless steel prop gains a bit over an aluminium one on an outboard.  Removing a prop that has welded itself on is a bit of a challenge. My one comes off every year so it is fairly easy but still requires a gear puller. 

    The first job is to remove any remnants of the anode. This is usually secured with a stainless cap headed Allen key set screw, which passes through into the prop nut.


    Once this is removed, the next task is to flatten out the aluminium tab washer. These are the same design as found in wheel bearings, but obviously more expensive because of the word ‘Boat’ . This can be done with a drift or a crappy old screwdriver that happens to be to hand. 2E466193-66AF-4F32-89E2-ED38D23FC09C.thumb.jpeg.5951b3b96e126c3070ef6b638db7797e.jpeg

    Once flat the nut will turn. 

    I used a state of the art adjustable spanner that was older than even the older members on here (no names, Geoff).


     I don’t fully remove the nut, I leave it on a few turns so that when the prop finally comes free it doesn’t go flying down the yard. 

    The next bit is the fun part- trying to get the thing off the shaft. If it has been on over a year then it most likely won’t tap off, so don’t risk damaging your prop or shaft by smashing the granny out of it. For removing I use a cheap and nasty 8” puller. I’m not a mechanic so I only use this once a year and I can’t warrant an expensive one.


    This is the sort of thing I have.

    Once in position it is wound up with a 17mm socket. The first time I did mine I had a 1/2” breaker bar on it, but today I just had a normal ratchet.  If you put massive amounts of pressure on it and it still doesn’t budge then maybe a gentle tap with the 2lb fine adjuster may help, but put a piece of wood against the boss to avoid damaging it. 

    If all else fails now you can turn to the oxyacetylene bottles, but remember when you are warming it up that it goes through a rubber stern gland and maybe cutlass bearing so be very careful not to damage these.  I personally would soak it with Plusgas and leave it a while before using heat. 7012DEAF-D4C1-4B1B-ACAC-C273C6157EB4.thumb.jpeg.4545e1243985158aaea7cf12017ae8fe.jpeg

    You can see from this picture that my puller is bent from someone going really hard on it, this shows the amount of force involved- enough to bend 14mm stud. 
    Once the prop comes off remove the nut completely and pull the prop off.  As the prop comes off there should be a square rod with it, this is known as a Woodruff key, it stops your prop from spinning on the shaft. You want to keep hold of this.


    I took my prop home so I could work on it on the bench, it’s always easier if you’re working comfortably. 

    To clean the prop up I used a 4” silicone carbide polishing wheel on a mini grinder. Being careful not to go too hard. I cleaned all the crud off the blades, getting as tight into the hub as possible. The very corners of the hub required a wire brush wheel, I used a brass one so as not to go too hard . Once all the scale was off then I fitted a softer polishing wheel to get a bit of a shine going.



    Make sure you wear a pair of safety goggles or at least glasses when using rotating tools, the bits flick all over the place and would cause serious damage to the eyes.  

    I gave the prop a quick going over with Brasso at the end, to draw any dirt out and give that little extra shine. 
    I'm going to leave it safely at home now so it doesn’t go missing while the boat's on the hard. These things are worth £700-800 so worth leaving off until the boat is ready to go back in the water. 

    Like most of you, I’m not a mechanical genius or marine engineer but I like to have a go myself, I find it rewarding as well as saving £1000s on running costs. If your prop doesn’t come straight off then stand back, have a think, have a beer or something and leave it. Talk to someone else who may have a plan, don’t rush in and wreck the thing.



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