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Two questions on Eastport Pram
Hello, plans builder here. I have two quick questions if somebody could help me I would appreciate it. The instruction book says that the skeg should be a few inches aft of the dagger board slot. Mine is about 1 inch behind the slot. Is that a problem? Also, I installed the skids last night. The screws Didn't seem to bite real hard into the skid material, But enough to hold the skids flat on the surface. I'm wondering if the screws are even necessary once the epoxy is cured. I put thickened epoxy on the bottom of the skids, as well as using fillets along the sides. Once this is cured, I would think I could just remove the screws. Any thoughts on this?
6 replies:
RE: Two questions on Eastport Pram
I thought white oak didn't "play well" with epoxy.... I like CaptainSkully's idea of using white oak for the pram's skids and skeg, but I'm wondering if others have used epoxy and white oak, and what your experiences have been.
Starting my Eastport Nesting Pram build, and intending to use it off the coast of Maine - so white oak would seem to be a good choice.
RE: Two questions on Eastport Pram
I didn't find out about white oak/epoxy thing until after my build was done. I think it may just be a matter of percentages, with oak having a tendency to be slightly more resistant than other, more porous woods.
The only problem I had was the oak sprung back at the bow for about 18" where the bend was the most severe. This happened a couple of days after the rub rails were glued in place. This was easily fixed with some more thickened epoxy and a clamp. I haven't had a problem with it since in 3 years of hard use.
A couple of things you can do to combat this tendency is to not have too smooth of a finish on the oak's bonding surface. This is even true when finishing oak furniture. If you sand past 220 grit, the finish will pool on the top of the wood and not soak in. So I'd make sure to sand to about 180 grit at most (maybe 120 grit) on the inside of the rail laminations and the top edge of the whiskey plank. This is for a mechanical bond, called "tooth".
Another thing you can do is to prep the mating surfaces with unthickened epoxy first, let that soak in for a minute, then apply the thickened stuff. This allows the epoxy to soak into the wood, which then bonds chemically to the thickened stuff in the middle.
Good luck with your build and keep us posted.
RE: Two questions on Eastport Pram
A follow-up question for Captain Skully (and any other Eastport Nesting Pram builders:
It seems the best way to be certain of where to drill the first "starter" hole for the daggerboard trunk's opening on the hull is to drill the hole before the trunk is epoxied onto the inner hull and bulkead surfaces. Once I've drilled that starter hole, I can proceed as the manual directs, and later, with the hull inverted, I can enlarge that hole and use a flush-cut router bit to cut out the full opening for the daggerboard. And, as you suggest, I'd rout the opening before attaching the skeg and skids.
Anyone see any problems with my sequencing?
Thanks,
Mark
RE: Two questions on Eastport Pram
I tried to think outside of the box on this one. Actually, the most accurate way of drilling the starter hole(s) for the daggerboard slot is to epoxy the daggerboard case in position on the centerline and let it cure. I then bought a drillbit extension long enough to reach all the way through the slot from the top of the boat, then drill starter holes at both ends and in the middle. This allows you to flip the boat and using a jigsaw, connect the dots to relieve the support material, then you can go in with the router. The drill bit that was used above is sized to be large enough to accomodate the bearing on the flush-cut bit used in the router. This allows you to plunge the flush-cut bit into the slot and moving clockwise, cut the hole to match the slot perfectly. In my case, there was a very slight curve to my slot. Then you can finish it off with a small radius round-over bit.
All of this is in my build blog:
RE: Two questions on Eastport Pram
Captain Skully,
Thanks very much for your reply and the link to your blog. Very helpful.
Mark
RE: Two questions on Eastport Pram
» Submitted by CaptainSkully - Wed, 9/20/17 » 3:44 PM
These are some of the same questions I had. Here's my feedback.
If you want to run a router around the daggerboard slot, then do so before you attach the skeg. That way the one inch gap is fine. It's a bit more difficult to route after installing the skeg since the router base stops the bit several inches from the end. It's much more difficult to fair that by hand to match the perfect routed edge.
I made my skids, skeg and rub rails out of white oak for durability sake and am very happy with the decision. I had trouble bending my skids enough to match the curve of the rocker and grab them with silicon bronze screws. Had to pre-drill and like you did butter them up with thickened epoxy. The screws bit well and secured the skids. I then created large fillets to increase the surface area bond between the skids and the bottom.
In the woodworking world, with today's glues, epoxies, etc. the screws are often times considered "clamps" to hold the parts in place until the adhesive cures. In a boat builders case, the screws are also there to assist in resisting shear forces that act on the boat, reinforcing the epoxy so much that the wood will fail before the joint does.