Setting crossbars with epoxy?

Last week I took my h-18 apart to do some repairs. I was inspecting the crossbar sockets. I was surprised that on all for corners, there seemed to be only two small areas of contact between each socket and crossbar.

I was thinking of putting some thickened epoxy in each socket, waxing up the crossbars (so it would release) and tightening up all the bolts.

It seems to me this would make the joint stiffer and stronger.

Has anyone here ever done this? Is it overkill? Worth the extra weight?

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87 hobie 18

I did it with my 16. I used Marine Tex and latter found out from M. Miller that it was probably too soft. He suggested Bondo, as it is much harder. The reason I did it was because the boat is old and I could pick one bow up about 15" before the other one came up. I drilled out all the rivets in the corners of the tramp, glued them up and re-riveted them. Hobie has the stainless rivets and sleeves. I then relaced the tramp. Even with the wrong epoxy, I went from 15'' to about 5'' so it stiffened the boat up. IF you don't want to go through all that, just relacing the tramp will do wonders for boat stiffness. I used a come a long to pre load the tramp frame about 1 1/2 ''. As I laced it I used a tapered wooden dowel and shoved it in the gommet hole to prevent loosing the tension of the lace. Worked great.
One more thing, if you do decide to re-rivet the boat, make sure it's square when you rivet it back together. You can do this by measuring diagonally across the boat from one bridle attachment to the opposite stern. If the 2 measurements are equal, the boat is square.


Hope that helps

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Christianity, if false, is of no importance, and if true, of infinite importance. The only thing it cannot be is moderately important.
C. S. Lewis (former atheist)

Thanks, sounds like it is worth the effort.

The 18 is a little different setup than the 16.

Looks like I have another project to put on the list.

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87 hobie 18

I would check out this link. Much more information than I gave you above.

http://www.thebeachcats.com/modules.php ... cle&sid=82

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Christianity, if false, is of no importance, and if true, of infinite importance. The only thing it cannot be is moderately important.
C. S. Lewis (former atheist)

I've done this with an 18 and a 17. I don't even think you have to bother with the wax. The forces are high enough that it will be separated the first time it blows at all. Be prepared for a big CRACK that sounds like the front crossmember is cracking. Then carry on normaly.

charly:

You had it exactly right in your first post. Use epoxy thickened with coloidal silica, I use West Systems. Wax the crossbar with several coats, polishing each in between. On a nice sunny day you can do this about every ten minutes. Get about 4 layers of wax on there for safety. You can polish pretty completely. You do not need to worry that the wax does not look like it is on there, it is. Be ready with the bolts. When you slather the mixture in the hull sockets generously and bolt the crossbar tightly to the hull it will seep out, just gather it and put it back in the bucket. If you are using the slow hardener, which I recommend, you may have time to use some of that on the other crossbar. If not, no worrys, just mix up some more. This is a relatively inexpensive upgrade to stiffen up the boat. Before you start the whole process I suggest you measure the cross from the bow to stern to see that you are square before you start. If you are a hair off you can correct it in this process by taking the mainsheet system and putting it on the long side. After you get the boat together and before you cinch up hard on the bolts measure the boat to get it square. Also make sure that the crossbars are level with each other. Let the whole thing alone for a week to allow the epoxy to get nice and hard. You will love the performance of your "new" boat.

Later,
Dan

Thanks everyone for the good info.

I did this repair back in July. Very easy, and it is much stiffer now. The slow hardener is definitely the way to go.

It surprised me how much epoxy it took in the sockets to make a complete seal.

I didn't end up measuring the squareness of the boat-I had it on the trailer which was level, and being an 18, just tightened the through bolts on each side of each hull.

worked great!

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87 hobie 18