The Boating Forum - Bent Strut - Any Way To Fix?

Gents,

I was installing my new prop shafts and cutlass bearings, and found out I have a bent rear strut. The port side went in fine and had good free movement and rotation. The starboard side was binding up.

Back when I removed my old shafts I saw that the starboard front strut was loose. I waited until I had the new shafts to remount it so I could use the shaft to align the strut.

So when I installed everything it was pretty obvious that it wasn't happy. I removed the front strut that I had remounted so I could evaluate the rear strut without being impacted by the front strut. Sure enough the shaft is not even close to being where its suppose to be. Evidently the previous owner ran aground or hit something and bent the strut. That's also what probably caused the front strut to come loose.

In the pictures below you can see how far the rear strut is off. This is with the front strut removed and I'm supporting the shaft in the middle of it's free play.

I think I know the answer to this question but I'll ask anyways. Is there some secret ole salty dog recipe for fixing this strut while still attached to the hull? I'm thinking probably not and I'll just have to replace it?

http://hargettprecision.com/Trojan/Strut_1.jpg
http://hargettprecision.com/Trojan/Strut_2.jpg

Check with a prop reconditioning company before you buy a new one.

Check with a prop reconditioning company before you buy a new one.
Exactly, most likely it's fixable, It will have to come off.

Gents,

I was installing my new prop shafts and cutlass bearings, and found out I have a bent rear strut. The port side went in fine and had good free movement and rotation. The starboard side was binding up.

Back when I removed my old shafts I saw that the starboard front strut was loose. I waited until I had the new shafts to remount it so I could use the shaft to align the strut.

So when I installed everything it was pretty obvious that it wasn't happy. I removed the front strut that I had remounted so I could evaluate the rear strut without being impacted by the front strut. Sure enough the shaft is not even close to being where its suppose to be. Evidently the previous owner ran aground or hit something and bent the strut. That's also what probably caused the front strut to come loose.

In the pictures below you can see how far the rear strut is off. This is with the front strut removed and I'm supporting the shaft in the middle of it's free play.

I think I know the answer to this question but I'll ask anyways. Is there some secret ole salty dog recipe for fixing this strut while still attached to the hull? I'm thinking probably not and I'll just have to replace it?

http://hargettprecision.com/Trojan/Strut_1.jpg
http://hargettprecision.com/Trojan/Strut_2.jpg

Fix while still attached?
I don't think so but it may be reparable off the vessel. If bronze, they can be bent to a point and they can be cut and welded. A new one might be available or might be difficult to find. As mentioned, try a good prop/welding shop.
Good luck.

Ok, I was able to fix it without taking it off. What a relief. So here's how I did it in case it can help someone in the future.

I removed the new shaft and new cutlass bearing. I machined an aluminum round piece that is 1.97" OD with a bore of 1.27" which basically is a solid cuttlass bearing. I then used a 4' section of the old prop shaft. I inserted the aluminum piece into the strut and then the 4' section of prop shaft in the bore of the aluminum piece. The aluminum piece is essential because it distributes the load around the whole circumference of the strut avoiding any oblong of the strut hole.

Then I placed a floor jack with blocks underneath the front tip of the shaft which is now hanging @ 3' in front of the strut. Raised the jack up to take all the slack out.

Now is when you have to take your time. I didn't just start cranking up the jack because when using the jack you don't get any "feel" for when you reach the yield point of the strut. The yield point is when a piece of metal actually bends. Anything before the yield point and the metal simply springs back to its previous position. I only needed @ 2" of swing at the end of a 6' bar so the actual movement of the strut is minimal, hense being very careful of when you reach the yield point.

So, to address the problem of not knowing where the yield point is I took measurements and made lots of "jacking" cycles. First off I placed a mark on the prop shaft to index its position relative to the strut (how far it was inserted into the strut). Then I placed a mark near the end of the shaft (travel mark).

Step 1: without any jack pressure and the shaft in its marked place, take a measurement from the ground up to the travel mark on the shaft. Let's say this is 20".

Step 2: carefully and slowly jack up the front of the prop shaft. Only go a small amount. I did something @ 5". I also had a friend watching the strut and mounting just to make sure everything was happy there. At the top of the travel take a measurement from the ground to the travel mark . Let's say this is 25".

Step 3: lower the jack and take another measurement as in Step 1. If this measurement is still 20" then the yield point has not been reached.

Repeat Step 2 and go a little higher, take another measurement and compare it to Step 1's measurement. The idea is to slowing approach the yield point by taking measurements. Once you hit the yield point you only go in very small increasing heights of the jack.

This process took several steps of increasing the jacking heights and took a lot of time but not screwing it up is more important. After I reached the yield point I went in small increased amounts (@1') and then completely removed the shaft and aluminum piece. I would reinstall the cuttlass bearing about half way and new shaft, slide it up and see where everything was. Then I reinstalled the aluminum piece and repeated the steps. I repeated this step several times. It took a couple of hours of this going slowly and watching everything carefully. But a couple of hours beats taking that strut off by a large margin. Hope this can help someone! cheers.

mine was folded over 30dg and was fixed.