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PostPosted: Thu Feb 06, 2014 6:09 pm 
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I have and old Hobie 16 (mid 80's). Recently the deck to hull seam let loose opening a crack about 3 1/2 feet along the outer deck to hull seam on the port hull between the front crossbar and bow. Almost didn't get back to shore while keeping the port hull barely above water. My repair plan is to remove hull, turn upside down, rough up, clean and re-bond as much separated seam as I can get to then grind out voids at each end of repair and re-glass. My question is what's the best bonding material to use in the initial seam repair? Any ideas on better repair approach?
Thanks,


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PostPosted: Mon Feb 10, 2014 9:39 am 
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Location: Jersey Shore
I think this is generally repaired the way you're describing. Flip the boat over, rough up and clean inside the joint as much as possible and then pour epoxy into the joint (you may need to use a syringe to get the epoxy into the tight areas). You'll need to figure out a way to clamp the joint back together while the epoxy cures, so best to do a dry run first. Also, you mentioned using glass, but there's really nothing to glass unless you're thinking of wrapping some glass fiber around the the seam. You may also try using a vacuum cleaner on the drain plug to help suck the epoxy into the hull.

Another thought would be to install a small access port in front of the front pylon in order to gain internal access to the hull so you could insure that the seam is fully bonded. Adding access ports in front of the pylon is generally considered a bad idea, but people have done it and I imagine if you only use a small port (4") it might give you just enough room to work without significantly weakening the hull.

sm


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PostPosted: Mon Feb 10, 2014 12:18 pm 
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I have heard that stuffing some matte glass into the joint would help get a better bond.

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PostPosted: Wed Feb 12, 2014 3:54 am 
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mmiller wrote:
I have heard the stuffing some matte glass into the joint would help get a better bond.


That's probably not a bad idea actually, since the matte would help hold the resin where you want it rather than it just running into the hull.

sm


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PostPosted: Mon Feb 17, 2014 5:14 am 
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Thanks all for the advice. I ended up executing the original repair plan minus the grinding and re-glassing at the ends of the crack. Instead I took a dremel with cut-off wheel and cut a groove as deep (approx. 1/2 in) as the wheel would let me go from where I could get crack separation back about a foot past visible crack line. It took two mixes to fill crack line area plus groove at each end. Pure resin will penetrate any crack as long as gravity's pulling in the right direction. Once it can't go down it will run out each end as it seeks level. Applied large binder clips every 6 inches or so on the first pass and used second pass to fill remaining voids. I recommend a syringe to apply and tape the deck to keep the waste and mess to a minimum. If I did it again I'd recommend a little cab-o-sil in the first mix to get it to just a little thicker and what ever you do make sure you mix the two parts the full two minutes recommended. I used the slow cure hardner but still had a little tackiness after 48 hrs and figure it only got mixed about a minute after timing the second mix. Also reworked the holes in the support posts (a lot of corrosion and some missing Al). Taped the outside of the hole, laid the hull over on its side, and troweled in some JB weld over the hole area building the inside up to get a final wall thickness of about 3/8 in thick while maintaining outside mold line. Match drill holes after posts are reseated in their castings.
I was going to wait until after sea trails to report on hopeful success but it doesn't look like that will happen for a while.


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PostPosted: Tue Jul 01, 2014 9:24 am 
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Just did this repair on an older (1981) Hobie 14. The starboard hull was reportedly taking on an excessive amount of water. We did a bubble test by spraying down the hull with soapy water and blowing in through the drain plug hole (about 2 or 3 good lung-fulls is all it takes to pressurize those small hulls). Bubbles formed along the outboard hull seam near the aft pylon.

Closer inspection revealed that the seam had some major voids over about a 2 foot length and a good portion of that area went clear though to the hull - there was no glue just silicon caulk. We flipped the boat over and used a small screw driver and razor blade to pick out all the old silicone. Then we roughed up the surfaces with sand paper and cleaned with acetone. We used West System Six10 epoxy adhesive which worked extremely well. The stuff comes in a caulk style canister that allows you to use a caulk gun. It also has a self mixing nozzle so you can just spread the seam open and squirt the epoxy into the voids. The Six10 epoxy is pre thickened so it doesn't run or drain into the void, it filled the gap perfectly. After about an hour sitting in the sun it was fully gelled up and after 24 hours, the hull was rock hard.

After sailing the boat for about 2 hours in solid 18-20mph breeze and 2-4 foot bay chop the hull had taken on maybe a cup of water (and that may have just been residual from the prior leakage). In fact a "woosh" of air came out when I popped the drain plug - I'd call it fixed!

Anyway, if you have to do this repair, I would highly recommend using West Six10 epoxy.

sm


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PostPosted: Tue Jul 01, 2014 1:21 pm 
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srm,
See my response from last Feb; since the deck had come completely free of the hull for a couple of feet I kept the epoxy wetter than what the Six10 sounds like to let it gravity slump across the whole joint / interface. Since the last post the boat's been out a number of times with no noticeable leakage.

Thanks for the response.


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