Keith Wilson
08-24-2002, 09:08 PM
I have a question about replacing steamed frames.
The boat in question is a Town Class sloop, a 17’ sailing dory, sort of, built in 1964 with copper-riveted pine lapstrake planking on oak frames. It has both sawn and steamed frames: fairly massive oak dory-style sawn frames, and white oak steamed frames, three between each pair of sawn frames. The steamed frames are much smaller, about 1-1/4” x 5/16” in cross-section. New Townies, BTW, don’t have steamed frames, I believe as a cost-saving measure.
The steamed frames are very brittle and rotten in places, particularly around the fastenings; I can pull some of them out by hand. There may have been some sort of grey goop between the frame and the plank, possibly old-style bedding compound that has hardened, or maybe just 38 years of accumulated paint dribbles. The side of the steamed frames against the planking is bare wood; and ALL of the deterioration is on this side.
I will be steaming new frames, bending them in against the existing lapstrake planks. I don’t like the idea of bare wood anywhere, even inside joints. I paint mating surfaces with red lead before the parts are assembled when I can. So how can I protect the face of the frame that bears on the planking? I can certainly CPES and paint the planks before putting in the frames, but what can I do with the frames themselves? Epoxy before steaming doesn’t seem like a good idea, nor paint, nor CPES. CPES with the frames in place might penetrate far enough, but I’d rather have a more robust coating.
With lapstrake planking there are always gaps between the frame and the planks, so sealing it up with any type of bedding doesn’t seem good either. Those gaps seem like wonderful places for crud and moisture and rot spores to accumulate, and I really don’t want to have to do this again – On the other hand, it did last 30 years or so, and in 30 years I’ll be 76, with luck, so maybe I shouldn’t worry about it, but the boat’s now in fresh water which is harder on wood, if easier on fasteners. The best I’ve come up with, which seems like a lot of work, is to pre-bend the frames, let them dry, CPES and paint the mating surface, then rivet ‘em into the hull. They’re small enough that the pre-bend wouldn’t have to be exact; they’ll tolerate a bit of cold bending. Any better ideas from the esteemed folk of this forum would be very much appreciated.
Here's a picture of the type:
http://www.doryclub.org/images/tc/tcf4.jpg
The boat in question is a Town Class sloop, a 17’ sailing dory, sort of, built in 1964 with copper-riveted pine lapstrake planking on oak frames. It has both sawn and steamed frames: fairly massive oak dory-style sawn frames, and white oak steamed frames, three between each pair of sawn frames. The steamed frames are much smaller, about 1-1/4” x 5/16” in cross-section. New Townies, BTW, don’t have steamed frames, I believe as a cost-saving measure.
The steamed frames are very brittle and rotten in places, particularly around the fastenings; I can pull some of them out by hand. There may have been some sort of grey goop between the frame and the plank, possibly old-style bedding compound that has hardened, or maybe just 38 years of accumulated paint dribbles. The side of the steamed frames against the planking is bare wood; and ALL of the deterioration is on this side.
I will be steaming new frames, bending them in against the existing lapstrake planks. I don’t like the idea of bare wood anywhere, even inside joints. I paint mating surfaces with red lead before the parts are assembled when I can. So how can I protect the face of the frame that bears on the planking? I can certainly CPES and paint the planks before putting in the frames, but what can I do with the frames themselves? Epoxy before steaming doesn’t seem like a good idea, nor paint, nor CPES. CPES with the frames in place might penetrate far enough, but I’d rather have a more robust coating.
With lapstrake planking there are always gaps between the frame and the planks, so sealing it up with any type of bedding doesn’t seem good either. Those gaps seem like wonderful places for crud and moisture and rot spores to accumulate, and I really don’t want to have to do this again – On the other hand, it did last 30 years or so, and in 30 years I’ll be 76, with luck, so maybe I shouldn’t worry about it, but the boat’s now in fresh water which is harder on wood, if easier on fasteners. The best I’ve come up with, which seems like a lot of work, is to pre-bend the frames, let them dry, CPES and paint the mating surface, then rivet ‘em into the hull. They’re small enough that the pre-bend wouldn’t have to be exact; they’ll tolerate a bit of cold bending. Any better ideas from the esteemed folk of this forum would be very much appreciated.
Here's a picture of the type:
http://www.doryclub.org/images/tc/tcf4.jpg