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Post by Amun Ra on Dec 30, 2011 22:25:25 GMT
Closer view to show the way the flow-coat has been lifted from the hull, which allowed water to seep forwards.
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Post by sailbleu on Dec 31, 2011 9:15:18 GMT
Oh that back cabine must look awful. Will you be doing a normal boxing in or are you going for a cross shaped box ? Like flippercarsons link on the previous page . (Nov 10 2010)
Greetings
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Post by Amun Ra on Dec 31, 2011 15:01:41 GMT
Thankfully the back cabin and everywhere else is covered up to avoid dust!
The bracket will be refitted to look pretty much as it did before it came out, so a white box again. However the difference will be that rather than being secured simply by being embedded in a block, the bracket will be through bolted and epoxied in. I will also fair in the underside of the hull, building up GRP around the bracket as it exits the hull underneath. The result will be a substantially stronger fitting.
Julian
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Post by tedp on Jan 1, 2012 8:08:05 GMT
On the basis of what I have seen in Sailbleu's repairs and now in the damage to Julian's boat the strut attachment in the hull is too lightly constructed to withstand any fore/aft leverage. Probably it wasn't designed with that in mind. Any rope wound between the propeller and the strut would result in immense leverage on the strut. The fact it has levered up the inner skin of the boat seems to indicate the attachment wasn't very securely bonded to the hull itself, and the inner skin wasn't bonded to the hull either.
I may be biased as I have always sailed plywood boats before having my present one, but if I had to replace the entire structure I would build one from plywood rather than rely on epoxy or polyester casting. If you start building up a new base from thick marine ply inside the box shown left over in Julian's photos, bonding it with epoxy inside the hull, you get a very strong structure. I would make a baseplate with two vertically positioned plates to either side of the strut where it comes into the hull. The strut can then be bolted in.
Add ply cross brackets ('knees') to the outside of the verticals and make sure the ply parts are bonded together with substantial epoxy fillets. I'm not sure I would epoxy the strut in if the bolts hold it securely in place, as long as there is no play after prolonged use. The advantage would be you can replace the strut if necessary, without cutting up the entire mount. Epoxied marine ply is extremely strong and won't rot.
Finally, in all repairs of this kind I would advise to make sure there is no water and particularly seawater remaining in the area to be repaired. It will adversely affect any bonding of resin.
Happy new year to you all.
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Post by sailbleu on Jan 5, 2012 9:10:56 GMT
Thankfully the back cabin and everywhere else is covered up to avoid dust! The bracket will be refitted to look pretty much as it did before it came out, so a white box again. However the difference will be that rather than being secured simply by being embedded in a block, the bracket will be through bolted and epoxied in. . I will also fair in the underside of the hull, building up GRP around the bracket as it exits the hull underneathThe result will be a substantially stronger fitting. Julian I forgot to mention that I also reinforced the outside by wrapping a layer of carbon fibre around the bracket and surrounding hull. This makes it all a bit stronger , and waterproof Then I egalized everthing with epoxy filler so it gradually takes the shape of the hull. I just hate the idea of repairs looking different than it originally was. The maniac thing in me you see. I'll see if I can trow in a picture of that. Regards
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Post by Amun Ra on Jan 5, 2012 19:54:08 GMT
Thanks Sailbleu, I agree with your view that the hull shape should be retained. In fact, the fitting should look better than new! I'm sure that this is one of those things that had the builder had a bigger budget to build with, he might well have chosen to do.
I should have some more pictures on Saturday of the reinforced fitting inside the boat, as well as the build-up outside around the bracket.
Best wishes
Julian
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Post by rxc on Jan 7, 2012 22:29:03 GMT
I have noticed that a LOT of Jeanneaus and Beneteaus here in France, in the 40-45 ft range, seem to have skegs for their propeller support instead of P-brackets. I haven't seen any particular correlation of length, and haven't seen the underside of any 43DSs, but I am wondering if any other Jeanneau owners, either here in Europe or in the US, have skegs instead of brackets. Now that I have read this thread, I am going to try to look more closely at boats that are hauled here, and see if I can find a pattern.
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Post by sailbleu on Jan 11, 2012 6:44:42 GMT
Thanks Sailbleu, I agree with your view that the hull shape should be retained. In fact, the fitting should look better than new! I'm sure that this is one of those things that had the builder had a bigger budget to build with, he might well have chosen to do. I should have some more pictures on Saturday of the reinforced fitting inside the boat, as well as the build-up outside around the bracket. Best wishes Julian Hi Julian , as promised , a few pics of the reinforment of the strut on the outside hull. You will notice the complete hull has been scraped up to the gelcoat/gelshield . Finished that some months ago , and by spring I intend to give it a 4 or 5 coats of epoxyresin . Not quit sure if I'll add copper to the mixure. You know , homemade coppercoat. Here's a close up from the extra carbonfibre on the joint of strut and hull. The red color are left overs from the old AF. I gradually reshaped the hull with thickened resin (using aerosil) after putting on the carbonband . Afterwards a real pain in the neck sanding the lot. I overlapped the strut for about an inch and 2 inches on the hull. Kind regards
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Post by Amun Ra on Jan 11, 2012 18:01:09 GMT
Here is a picture of the P bracket, glassed in place. You can see how much of the old flow-coating has been removed, exposing the hull underneath. Thankfully the damaged area, where the flow coating had been lifted from the hull was reasonable easy to cut away and dry out. Julian
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Post by Amun Ra on Jan 11, 2012 18:04:47 GMT
In this picture the flow coating has been applied to cover the P bracket. A supporting strut has been fitted across through the top of the bracket. Outside, the bracket has been further strengthened by building up GRP around the bracket where it emerges from the hull - much as Sailbleu has done. I will no longer be depending on a bit of sealant to remain watertight! Best wishes Julian
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Post by sailbleu on Jan 12, 2012 9:00:51 GMT
Julian,
I must say this is a strange way for repairing the P-bracket. Agreed , the supports on both sides will surely make the whole stronger in terms of port/starboard forces. But I have the impressing that the most vulnerable direction - being the bowside and remember how the damage occurred - is left unattended. I thought you would have the bracket cased-in and filled up with new resin again to be finally glassed onto the innnerhull . I guess the shipyard knows what they are doing of course.
Any idea on the repair bill yet ? I hope I'm not prying here , but I'm just curious how much I saved by doing the job myself.
Regards
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Post by Amun Ra on Jan 12, 2012 21:30:14 GMT
Sailbleu,
You make an interesting point about the fore-aft vulnerability of the P bracket. I did a fair amount of research talking to marine surveyors (as well as being one myself) to establish exactly how vulnerable a P bracket is, and what would be the best form of protection.
It was interesting to see that the damage to my bracket was in the lateral plane, not longitudinal, or fore and aft. It appeared that the rope, when caught, had caused the bracket to attempt to twist, exacerbated by the rotating prop no doubt.
If it was a pure fore and aft force, I would have expected compression fracturing at the front of the bracket and expansion cracking at the rear. I had neither, just cracking caused by a twisting force.
Not surprisingly, the shipwright in the yard has repaired countless P brackets and knows a good design from a bad one - even if he couldn't describe the science behind his repair work! I think the combination of a big increase in GRP built up around the hull, both inside and outside, together with a bracing bolt through-bolted has significantly strengthened my fitting. I don't think a block of resin, as the fitting used to be is very robust. It is vulnerable to lateral and longitudinal loads - and our experience is testament to this.
My hope now is I never have to think about it again.
As far as cost is concerned, happy to PM you the bill, but you can be assured you have saved yourself a lot of money!
Thank you very much for your support through this, it has been really helpful to share the experience.
Best wishes
Julian
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Post by sailbleu on Jan 14, 2012 5:48:19 GMT
Hi Julian,
obviously there are different ways of getting a P-bracket damage. Mine was clearly a matter of for/aft forces , as my story and pictures indicate. But I guess you can make it as stronge as can be , eventually something has got to give. I my case (and probably also yours) it was the engine that stalled. Lucky us. I remember having to put my diving gear on and cutting the rope (with a handsaw) free. At the time I did not notice the extended distance between the cutless bearing and the ropecutter/propeller due to 3 or 4 layers of rope. Once cut away , apparently everything fell into place again. Beside the interior cracks of course. Maybe it all depends how stronge the engine is , mine is a 50hp . Perhaps a 75hp would of ripped the engine off the silent blocks or would of torn the sealing nut off the propshaft , giving it wings and leaving the boat without propulsion. In a way I think we were both lucky. I agree , not particularly the kind of luck one should look for , but it could of been worse. We where both able to repair or have the repair done in a controlled environment of our choosing. I've read more dramatic stories.
Anyway , problem solved , and lets try not to develop an allergy for drifting ropes :-)
Kind regards
Edit: by the way , you've got a PM
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Post by jeroen on Aug 14, 2016 7:39:22 GMT
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