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Advice wanted on strengthening chainplates...Urgent.

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1 hour ago, Badgered Cat said:

It all comes down to how you manufacture the part. There is ways to isolate the carbon fibre from being in contact of the stainless steel. I am not going to try and explain here, as it would be too difficult to explain by  messaging. Trust me, I know, as I have been in the industry for many years.

Totally agree but in this part in question any isolation of the carbon will greatly reduce the strength of the fitting as it is the stainless carrying the load.....the isolation becomes the weak link. Seems to me that the same high grade marine stainless throughout would be stronger.

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Hi cdoch.  It is the way in which the part is manufactured, is what gains its strength. and avoidance of any corrosion. Carbon fibre has been used many situations where there is very high stress loads and in a marine environment without any problem. But making carbon parts is not for the amateur.  Anyhow it does not matter, I am not going down this path anyway, I will stick with crappy alloy castings, I may as well kept to the alloy on the side chain plates and kept the boat more original. As going to stainless steel, I dont get, when it is only on the side and not the front. But that does not matter now. I have now fixed the boat, and it is now might strong. As I have boosted the strength in the glass  where the chain plates attached, and strengthened this npoint now to withstand the roaring forties, in which I live.

Cheers everybody, and many thanks for everyones input, I really do appreciate the comments. (We may as well move on from this.)

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Thanks exhogger.

Mine is all fixed. Super, super.....massively super strong now, and was cheaper to fix than buying stainless steel plate and bending it. Plus it looks unnoticeable as a repair by comparison, and looking more very original, which is more to the class rules....I so believe, than having non conventional parts added to thee boat.

I raced it last weekend, and pushed it ever so hard on the reaches, with the bows burying, and me just sheeting on harder, to drive it through the bury, rather than back it off. I absolutely punished the boat, and no way was it going to give in on me. So much so, that I was travelling faster than Hobie 16 and Nacra 5.7 on the reaches. And upwind I was travelling faster and higher than B14. So I think I have it all worked out. Going massively fast, and not wanting to break, flex, nor take on anymore water than just a few little drips in each hull, and that is after 4.5 hours of hard driving, competitively sailing (racing).

I am very happy.  

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Hi All, have an old maricat 4.3 and a leak in a pontoon between the deck and the hull, which I have found aft. The black gunwale has lifted a few mm for about 2cms can I bung it up with epoxy or should I put a plate top and bottom and clamp closed? are there any issues drilling through the deck/hull/gunwale seam?

Regards, Mike, Bicheno

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Hi Mike.

I gather you are in Bicheno, Tas..

Where exactly aft , is the separation in your hull.  If it is not where the chainplates are located then , I would not be bolting plates to the gunwhale. If you are good at fibreglassing then it will e an easy fix. Just check that the only damage is separation at the join on the gunwhale.  Look for any hairline cracks in he gelcoat, on the sides of the hulls, at the location of the said separation. If here are no visible hairline cracks then you probable need to just fix the point of separation.

You will need to open that seam a little, you could use a couple of screwdrivers. Be very careful, as you don't want to open it up TOO MUCH!. Just a very tiny little. Then you will need to use a very thin file, or better still if you have access to a dremel tool or equivalent brand. If using a hand rotary tool like a dremel, then put a very tiny grinding wheel or disc, or abrasive disc onto the tool, to clean the joint firstly, and secondly with a course wheel or disc, to enable a roughened surface for the new epoxy to grip, by you offering a key to the surface that you have ground. Again DONT GRIND TOO MUCH. Otherwise you will be making a terrible big job out of nothing. If you have a compressor, blow out the roughened seam with compress air. And now also tape up using masking tape, your black gunwhale rubber, so that you do not get epoxy in or on the rubber, make certain you cover it well, and for the full length of the repair, and a little more each end. Also mask around the area near this repair on the hull, so as not to get epoxy on you hull where you don't need it.  

Then using west epoxy or similar generic brand make up enough epoxy to squeeze into the gap. Put a tiny little aside to wet the seams. For the rest of the epoxy, may I suggest that you get a little chop strand mat, and totally shred it into very tiny little pieces, and you could also mix in just a tiny amount of microballoons, personally I mix up my bog mixture using just finely chopped and shredded chop strand mat, as this method offers maximum strength. You then need to wet the seams with the little epoxy that you places aside. After that, get a tiny spatula and collect a little of the epoxy bog mixture on the end of it and force it into the gap, just small little amounts at a time, until it is all done and completed. Remember you need to force it in, all f the way through to the back of the seam, and even if little amounts fall into the inside of the hull. That is why a just little amounts at a time.

Let he job harden, then clean the edges back, with a course rasp or file, finishing off with a finer file. Remove the masking from rubber and the hull. Put rubber back onto the boat, with a bead of marine grade sikaflex, placed along that area of the seam, be careful that only need a small bead of Sikaflex along the full length, TOO MUCH and you will have a yuk mess to clean up, too little and it wont be enough to help bond the black gunwhale rubber. Use a rubber or wooden mallet to hit the rubber all the way home, over the seam. You may need a couple of clamps to clamp the rubber in place, until the sikalex hardens. It just depends as to how much the rubber has been stretched, in doing the repair.

I hope this as been of help. I am a qualified and well experienced FibreGlass  fabricator and technician of many years, of which was building fibreglass Kenworth Truck Bodies and components, Along with many other fibreglassing jobs over the many, many years. So if you get stuck, or don't know enough, then please get back to me. If you are in Tasmania, it is a shame that you are at Bicheno, as I am near Beaconsfield, and I would have been more than happy, to assist you with this repair.

Cheers David.

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