epoxy or caulk for daggerboard trunk?

[David Walker]

I'm building a 16' plywood sailing skiff, sealed with epoxy inside and out. I'm wondering whether to waterproof the daggerboard joint with marine caulk, or waterproof it (and glue it on for eternity) with epoxy mixed to peanut butter consistency. Does anyone have an opinion on the better method? Am I likely to regret gluing it permanently with epoxy for any reason?

Thanks,
David Walker

[garyspear]

I have decided to go with a marine adhesive selant to install the centerboard trunk. definately not 5200. something a little less aggressive. I would hold it to the boat with screws through the keelson. I will be bedding a removeable keel thus making this sort of attachment method possible.

This follows the advice from one of the lapstrake boatbuilding books.

[Thorne]

I used Vulkem 116 to bed the centerboard case on my dory, but was unsure about my skill on fitting the case to the bottom planks, as well as the potential need to remove the case if the centerboard failed or jammed

If I was building new and making a daggerboard trunk as you are, I think that using the same methods as for the rest of the boat would make sense -- so I'd go with epoxy. The top of the daggerboard trunk is being braced / supported by one of the thwarts, correct?

[David Walker]

Thorne, daggerboard trunk is braced by a thwart, sort of...the boat is a Perfect Skiff, a design that appeared in WB some years ago. The top front edge of the trunk is screwed into a stout oak cross member at the top of the forward bulkhead, if that makes any sense. The trunk fit is good and snug at the bottom, no gaps, and six bolts hold it down. Thanks, David

[Thorne]

I'm chasing a leak and suspect the CB case as the source -- yet another reason to use epoxy in your case. I was restoring / retrofitting not building new, but sure wish the CB case was sealed up a bit better...

Really, with a well-supported daggerboard case, I don't see any reason to not build it just like the rest of the boat and use thickened epoxy. You can always make the cap of the daggerboard case removable, bed it in Dolphinite or whatever rather than epoxy, allowing easy access to the interior of the case.

[Stephen Hutchins]

Why not caulk it, and if you find that insufficient, you can always go back and epoxy it.

[DJM]

I would use caulk, the Vulkem Thorne mentions is very good for that. My reasoning is that I might decide to change the rig one day, and it would be easier to move/remove the trunk if it were caulked rather than glued. I used the Home Depot PL sealant and have had no leaks ( so far). I also screwed the logs in place with #12 bronze screws every 6" or so.

You may also decide you would rather have a centerboard in place of the dagger board.

[johnw]

Use something flexible. Trunks always flex a bit, and epoxy will crack.

[gary porter]

5200

[Steve Lansdowne]

4200. 5200 may flex, but it is on there FOR GOOD.

[David Walker]

Thanks to everyone who replied. I'm going to try the caulk/sealant first, and reconsider the epoxy if I'm not satisifed. David

[W Grabow]

I built a 15 1/2' sailing skiff with a daggerboard trunk and used epoxy to attach it. Sailed it for three years (in Panama with year-around sailing) with no problems, then sold it. I experimented a bit with daggerboard shapes, but did not see any future need to change the trunk itself, so epoxy was an easy choice. Epoxy is such a great adhesive, distributing stresses, that I generally use few metal fasteners other than to hold parts together while the adhesive sets.