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Old 07-11-2009, 09:18   #1
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Lashing Points without Drilling into Core ?

I would love to add covers for my salon windows, but I can see that previous (factory) snap installation for the dodger windows were not great. Some are loose in their holes and many are poorly sealed. I'm certainly glad it is not a balsa core.

It seems that some smart guy should have come up with a way to epoxy a light load lashing point to the skin without drilling. Something low profile and unobtrusive within limits. My windows are going because of the sun, but I can't see drilling and potting 30-40 holes the task will require. the risk/risk balance doesn't seem good enough.
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Old 07-11-2009, 10:36   #2
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Glue-on velcro? (you did say light load)
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Old 07-11-2009, 11:18   #3
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I have seen plenty of screw in canvas connectors done successfully. I suspect someone did yours wrong. The loose ones I would replace and rebed them with some 5200.

I don't know how well Velcro is going to work when it is blowing like hell. I guess if you use enough it will work...but then you have an ugly factor of stick on Velcro everywhere.

You might want to consult with a canvas maker to get ideas.
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Old 07-11-2009, 12:35   #4
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All the screw in push snaps on my 40 year old boat are holding up just fine. I surmize either the holes were drilled too large on initial installation or the layup is paper thin, too thin to hold the fasteners on your boat. More likely the former but being a catamaran, the builder may have been exploring the boundaries of light construction.

I'd do a light countersink of the pukas, plug the holes with with epoxy thickened with West Systems 404 filler additive, and redrill the holes. If you cover the filled holes with waxpaper and secure a flat surface over them while they are curing, you probably wouldn't even have to sand the epoxy plugs. That should fix the problem.

If you bed them with 5200 on reinstallation, don't plan on ever removing them. 5200 has got a reputation as one hell of an adhesive. Personally, I like LifeCaulk as a bedding compound as its much less of an adhesive and remains pliable (better seal) practically forever.
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Old 07-11-2009, 13:23   #5
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All good input.

Quote:
Originally Posted by roverhi View Post
All the screw in push snaps on my 40 year old boat are holding up just fine. I surmize either the holes were drilled too large on initial installation or the layup is paper thin, too thin to hold the fasteners on your boat. More likely the former but being a catamaran, the builder may have been exploring the boundaries of light construction.

I'd do a light countersink of the pukas, plug the holes with with epoxy thickened with West Systems 404 filler additive, and redrill the holes. If you cover the filled holes with waxpaper and secure a flat surface over them while they are curing, you probably wouldn't even have to sand the epoxy plugs. That should fix the problem.

If you bed them with 5200 on reinstallation, don't plan on ever removing them. 5200 has got a reputation as one hell of an adhesive. Personally, I like LifeCaulk as a bedding compound as its much less of an adhesive and remains pliable (better seal) practically forever.
I have used the glue-on velcro successfully for many things, particularly if I was testing the location of something lightweight. In fact, I have one winch handle pocket that was secured that way for years. It was in a protected corner, and I used a lot of velcro. Also solar panels. Yes, that can work. It is actually best for items you do not intend to move often.

Yes, the skin is relatively thin, but I would not say the cabin top is weak. Specifically, I am talking about the hard dodger, and I'm sure they cut it thin there, since many boats would just use fabric. It has ~ 1 1/2 inches of foam too, so it is fairly strong. The cabin top has a much thicker skin - about 3/16" over ~1" foam - and that is where I will be working. The hulls are solid below the waterline and have fairly conservative skins on the sides.

Yes, I think the holes may have been oversize. The few I have mounted on the cabin myself felt very secure, and I have broken screws off twice from under drilling. The challenge is that the shanks of the twist-locks were brass and wouldn't take much. I now use the twist-locks with 2 mounting screws.

I think drilling them the correct size will work, sealing them with 5200. Still I think the idea of skin-mount fasteners that avoid drilling is worth discussion. Small epoxy-on frp pad eyes, for example, could be handy. A strength of ~ 600 pounds should be attainable, with a working load of over 100 pounds (for a 1" square fitting - larger sizes could be stronger).

Food for thought.
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Old 07-11-2009, 16:04   #6
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Anything. With polyurethane glue.

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