I guess that I can’t decide between “traditional” and “modern” boatbuilding methods, and have been wondering about combining some of the best features of each. Cold molded veneers may be used as a last resort to rescue old carvel planked boats, but I have never seen a description of new construction using cold molding over carvel planking (as opposed to cold molding over strip planking). I would appreciate comments and suggestions from experienced builders about the following proposed construction method. Final design is not chosen, but I am thinking about a traditional cruising sailboat in the 35-foot range.
1. Upside-down hull construction.
2. Laminated or steam bent frames over molds at each station, i.e., Herreshoff method.
3. Planking with 1/2” or 3/8” stock riveted or screwed to frames.
4. Thickened epoxy to fill small gaps between planks, prior to fairing and application of diagonal cold-molded veneers to achieve the design hull thickness.
5. Apply glass below the waterline for abrasion resistance
6. External lead ballast
In suggesting this method, I’m making the following assumptions – please let me know whether or not you think they’re valid:
1. Spiling and fitting planks would be more pleasant and interesting than stripping.
2. The fit of the inner planking could be a little less precise than traditional full thickness planking with caulked seams.
3. The inner planking layer would weigh less than a similar thickness of strip plank with epoxy.
4. The thin inner planking would be easier to bend and fasten to the frames than full thickness planking.
5. Planking stock of 3/8” or 1/2” would be thick enough to result in a fair hull before the cold molding is applied.
6. Butt blocks and shorter stock could be used more liberally on the inner planking since the cold molded layers would provide some dimensional stability.
7. If the planks were fit dry to the frames, one wouldn’t have to deal with removing epoxy from the inside of the hull during planking.
8. The interior of the hull would have a more traditional appearance than one gets with strip planking.
9. The frames provide a structural element for attaching furniture, ceiling, and bulkheads.
10. Plans for a traditionally built boat could be used without significant modification for cold molding, at least as far as mold shape and spacing are concerned
11. The resulting hull would be stiffer than a similar boat that was traditionally planked
Should the inner planks be glued to the frames, or just dry fastened?
Would rivets or screws be better to fasten the thin inner planking to the frames?
Pros and cons of laminated vs steam bent frames?
Difference in time and materials cost for this method vs strip planking?
Thanks in advance for allowing me to tap into your collective wisdom and experience.
[ 09-27-2004, 10:26 PM: Message edited by: Dave Lesser ]