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Old 20-09-2017, 22:11   #1
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How is the shaft strut usually attached to the hull?

I may need to refabricate or fix the support that holds the shaft in place. I don't see any bolts on the outside or inside the hull. I believe the support is made of metal. Anyone have experience with these? How are they usually attached? Click image for larger version

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Old 20-09-2017, 22:19   #2
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Re: How is the shaft strut usually attached to the hull?

Not familiar with the Bene's, so hopefully someone who is will answer. But, is there a "pod" or "pyramid" inside the hull above the strut? On our boat the strut just extends upwards into the hull in a big blob of resin. Then a glass pod/pyramid over that. The idea is that if you wrap the prop with a line the resin will fail, the strut will rip out, but the hull will be intact, no hole. If you want to work on the strut you have to chip away the resin blob, and put it back (so a task you really have to need to do).

Don't know if that's how yours is built, but if there's a pod inside about 4-6" tall then that's what I'd guess.
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Old 20-09-2017, 22:43   #3
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Re: How is the shaft strut usually attached to the hull?

Interesting that they build that in a sacrificial way. I believe there is a bump on the inside. That is supported on both sides. I will post a photo when I get to it later. Thank you.
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Old 20-09-2017, 23:00   #4
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Re: How is the shaft strut usually attached to the hull?

Often, on the outside of the boat, the strut's foot/base is bolted into a shallow purpose built recess in the hull. And then once it's bolted in place, it gets covered with fairing compound, & occassionally a light layer of glass. That way there's less drag.

You should be able to tell difference in materials by tapping on the hull (soundiing) with a mallet, or the butt of a screwdriver. As in to determine where there's solid or cored glass hull, where there's the strut's foot covered in fairing etc.

One other possibility is that you have a composite strut. Meaning that it's made of fiberglass or carbon fiber, with a standard strut bearing inside of this. So don't go carving on things randomly, looking for the strut's metal base until you rule this out.
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Old 20-09-2017, 23:23   #5
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Re: How is the shaft strut usually attached to the hull?

Thank you uncivilized for your response. Once I get the boat out of the water, I will do some tapping around (should be later today). I know for a fact that the base of the strut has some sealent (like 4200) around it.
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Old 20-09-2017, 23:25   #6
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Re: How is the shaft strut usually attached to the hull?

Quote:
Originally Posted by hd002e View Post
I may need to refabricate or fix the support that holds the shaft in place. I don't see any bolts on the outside or inside the hull. I believe the support is made of metal. Anyone have experience with these? How are they usually attached? Attachment 156460
The strut is called a "P bracket". It's usually made of bronze and is usually bolted through the hull into a beam or other structural member. Some, like mine, have feet which go into a molded recess in the outer skin of the hull. Mine has 16 large bronze bolts which go through one of my ring frames.

On boats without ring frames, the p-bracket goes through a slot in the hull and there is usually a bracket inside the hull which is bolted on with the bolt heads countersunk into the outer skin of the hull and glassed in. That's probably the type you have. Here is a good article on how to remove it:

https://coxengineering.sharepoint.co.../Pbracket.aspx

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Old 21-09-2017, 06:03   #7
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Re: How is the shaft strut usually attached to the hull?

Quote:
Originally Posted by Dockhead View Post
The strut is called a "P bracket". It's usually made of bronze and is usually bolted through the hull into a beam or other structural member. Some, like mine, have feet which go into a molded recess in the outer skin of the hull. Mine has 16 large bronze bolts which go through one of my ring frames.

On boats without ring frames, the p-bracket goes through a slot in the hull and there is usually a bracket inside the hull which is bolted on with the bolt heads countersunk into the outer skin of the hull and glassed in. That's probably the type you have. Here is a good article on how to remove it:

https://coxengineering.sharepoint.co.../Pbracket.aspx

Attachment 156463
Dockhead's explanation and illustration are essentially correct for the Beneteaus although the arrangement on the Beneteau is somewhat more complex. BeneteauUSA has a technical bulletin on the repair of the P-Bracket and you can contact Ward Richardson at 1-843-629-5300 to obtain a copy. Alternately, send me a PM with your email address and I will forward a copy to you.

FWIW...
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Old 21-09-2017, 13:05   #8
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Re: How is the shaft strut usually attached to the hull?

Quote:
Originally Posted by hd002e View Post
I may need to refabricate or fix the support that holds the shaft in place. I don't see any bolts on the outside or inside the hull. I believe the support is made of metal. Anyone have experience with these? How are they usually attached? Attachment 156460
In the UK we call them a "P" bracket. The bracket has wings that sit on the bilge inside the hull. To remove the old bracket you need to grind away GRP around the bracket keeping as much of the old GRP as you can.
You can find "P" brackets on line, some have wings at the top of the bracket, others just a hole which you can afix a fairly large nut and bolt to give some grip for the grp to adhere to. Once you have removed the old bracket place the prop shaft back into the cutlass bearing of the new bracket and re attache it to the gear box.
With a bit of jigging around with small blocks of wood for support get the shaft as strait as possible and glass the end of the bracket with a few removable lengths of glass. Test it to make sure it is strait. If it is it is just a matter of building up layers of glass round the interior of the hull/bracket.
Build up the glass making sure you distribute the loads to the adjoining hull and avoid voids. On the outside of the hull fill the voids with glass putty and make smooth.
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Old 22-09-2017, 05:14   #9
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Re: How is the shaft strut usually attached to the hull?

Keep in mind that if you do have to pull the p-bracket, & replace it or remount it, that things must be lined up absolutely perfectly. Otherwise it'll be nigh on impossible to get the shaft to mate up with the transmission properly.
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