It already damaged mine a bit until I realized how much damage was being done.
I also definitely do not recommend a pipe wrench.
Need Help: Prop Shaft Jam Nut Won’t Budge
- Thread starter testingthewaters91
- Start date
I also definitely do not recommend a pipe wrench.
And did you keep them, or change them out?
I've owned, and operated boats that were in excess of 50 years old on which the silicone bronze thruhulls were quite functional. A proper thruhull requires regular lapping, to keep the cone edges sharp and maintain a machined fit over time.
One of the easiest ways to sink a boat would be to add brass to steel and possibly aluminium engine cooling lines in saltwater.
Short answer "totally". I was once advised don't take that boat out unless you have a spare sheer pin. That advice was validated the same day that I was operating under the belief that I didn't need a paddle because I could always use a ski to get back. Nowadays I've heard of everything and don't know anything so kinda count on you guys pointing me in the right direction most of the time.
I'm quite sure you can rest assured that the load testing on those bolts found that having that jam, not next to the propeller is significantly more safe.
And just because 500 people get away with it for a couple of years, that doesn't mean you won't be the one who loses the propeller. It happens and that's why the standard exists.
Use a 2x4 of the right length such that one of the propeller blades is horizontal and just sits on the top of the 2x4 that is placed on the ground vertically. Then use a socket wrench and attempt to remove the nut. Are you sure you have to rotate counterclockwise to remove it? Try clockwise.
If those fails, use dermal tool and make deep notch on both sides of the nut then place a screwdriver in the notch and twist it. The nut should fall off easily. After replacing with new nuts, rub lanoline on the shaft thread so can remove it easily.
You may consider removing the propeller and cleaning the shaft and rubbing it with lanoline before reasonabling it.
If those fails, use dermal tool and make deep notch on both sides of the nut then place a screwdriver in the notch and twist it. The nut should fall off easily. After replacing with new nuts, rub lanoline on the shaft thread so can remove it easily.
You may consider removing the propeller and cleaning the shaft and rubbing it with lanoline before reasonabling it.
Hey folks, just wanted to share an update and a little lesson learned while pulling the prop nuts off my shaft. I ended up using the woodblock method and, yes, a pipe wrench. Not ideal—I’d definitely recommend using the proper-sized hex socket if you have it—but in a pinch, the pipe wrench and woodblock got the job done.
Once I broke the tension on the jam nut, it backed off without much drama. But what surprised me most was the taller, wrongly placed nut. The moment the jam nut came off, I reached for the larger nut and found it completely loose—I could literally spin it off with two fingers. I expected both nuts to be tight, but evidently vibration over time can break that tension or walk the larger nut back.
You can see the vibration pattern in the chart above; it's possible that’s what contributed to it. Either way, lesson learned: don't assume both nuts are secure just because one is.
I’ll be reinstalling them the correct way—jam nut first, taller nut second, then locking everything down with a fresh cotter pin.
Photos attached in case anyone’s walking through the same job. Hope this helps someone else out there.
Once I broke the tension on the jam nut, it backed off without much drama. But what surprised me most was the taller, wrongly placed nut. The moment the jam nut came off, I reached for the larger nut and found it completely loose—I could literally spin it off with two fingers. I expected both nuts to be tight, but evidently vibration over time can break that tension or walk the larger nut back.
You can see the vibration pattern in the chart above; it's possible that’s what contributed to it. Either way, lesson learned: don't assume both nuts are secure just because one is.
I’ll be reinstalling them the correct way—jam nut first, taller nut second, then locking everything down with a fresh cotter pin.
Photos attached in case anyone’s walking through the same job. Hope this helps someone else out there.
Attachments
Good! Now clean up the scarred nuts & coat the shaft with Lanocote grease prior to installing the nuts & cotter pin. Buy the specific size box end wrench (single wrench only) from Amazon to reinstall the nuts and for future use. Use the wood block method again to prevent prop / shaft rotation, in the opposing direction, to facilitate tightening.
jssailem
SBO Weather and Forecasting Forum Jim & John
- Oct 22, 2014
- 23,237
Not brass. Bronze. Similar color. Grossly different properties.
I suspected you were going to remove the nuts. Be sure to get the proper replacements.
In for a penny, in for a pound. Are you removing the prop?
Review MainSail's Prop Install info.
I suspected you were going to remove the nuts. Be sure to get the proper replacements.
In for a penny, in for a pound. Are you removing the prop?
Review MainSail's Prop Install info.
Thank you! I'll do it as you say. The only issue I have now is that I suspect these nuts are brass, and not bronze. When gouged a bit they have a very yellow-golden color as seen in the above photograph.
Thoughts, anyone?
No, don't do this. The last thing want is a nut that comes off easily.
It is very unlikely that the nuts are brass. They are most likely bronze. And, do not lubricate the shaft or the threads. The nuts work because of friction and tension on the threads. Lubrication will reduce the friction making it easier for the nuts to loosen, which is what you do not want to happen.
jssailem
SBO Weather and Forecasting Forum Jim & John
- Oct 22, 2014
- 23,237
That pink color on the nut suggest there has been some galvanic corrosion occurring.
Brass has higher malleability than bronze or zinc. The relatively low melting point of brass and its fluidity make it a relatively easy material to cast. Brass can range in surface color from red to yellow to gold to silver depending on the zinc content.
Brass nuts would have malformed with your first attempt to remove the nuts.
Brass has higher malleability than bronze or zinc. The relatively low melting point of brass and its fluidity make it a relatively easy material to cast. Brass can range in surface color from red to yellow to gold to silver depending on the zinc content.
Brass nuts would have malformed with your first attempt to remove the nuts.
Silicon bronze, NOT brass. If someone has been using brass instead of the more expensive silicon bronze, on a boat I was looking at, my offer would drop 50%. Whichever owner used the inferior, cheaper brass, here, may well have done a lot more corner cutting, elsewhere.
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