View Full Version : converting plywood on frame to stitch and glue

mike from Boston
11-24-2004, 08:28 AM
Hi Everyone.

I am contemplating building a old Monk designed plywood on frame boat, and I would like to build it using stitch and glue technique. Can this be done safely/practically without major modifications? The original design calls for bronze ring nails as fasteners for plywood sheets. Boat is 15'9" sailboat, that I will use as low power (10hp) fishing boat.

Thanks in advance for your comments/help!


Tom Lathrop
11-24-2004, 09:02 AM

Sam Devlin givers some notes on this in his book. I did convert a plywood on frame 15 1/2' racing sailboat to composite construction so it can be done.

The main problem is getting the layout of the bottom and topsides panels. Actually, that is about the only real problem other than formulating the glass tape requirements for the joints.

I suggest that you make a "lift" model and take the panel layouts off that. Sam also describes constructing a lift model in the book. I've done that a couple of times and it is not too difficult. It does need careful work on the model for accuracy, but it's fun to see the boat emerge.

Keith Wilson
11-24-2004, 11:54 AM
There's a good article by Sam Devlin on precisely that in WB #106. Since most stitch-and-glue boats' shapes are defined by the shape of the plywood panels, a lot of what needs to be done is to find the true flat panel shapes. Devlin explains his method (using a model) quite clearly in the article. You could also use a computer to do the panel expansions.

[ 12-03-2004, 05:39 PM: Message edited by: Keith Wilson ]

L.W. Baxter
11-24-2004, 06:08 PM


mike from Boston
12-03-2004, 08:13 AM
Thanks everyone for your thoughts. Why? I guess I perceicve stitch and glue to be simpler that constructing the strongback and frames, this may not be true depending on what I read in the Devlin articles. Anyway, thanks again!


12-03-2004, 04:19 PM
Mike, I doubt if it will be simpler. To hold the panels in place and keep the hull from warping all out of shape you'll have to build either male station molds or bulkheads to lay the panels over top of or a female basket mold to lay the panels inside of unless the boat is an extremely simple, small design and even then its still a good idea. Good luck

Mike Vogdes
12-03-2004, 05:03 PM
I would have to disagree. As Tom pointed out above, determining the hull panels will be the most dificult part of the project, I too would lift them from a scale model. For a 16' hull you should not need a building form or jig. You would stitch the bottom panels at the keel line, stitch the sides to the bottom panels then stitch the transom and frames in. The hull should go together very quickly with bracing and spreaders only.

12-03-2004, 06:39 PM
I guess you're a better boatbuilder than I am, Mike :D I've made plywood boats both ways and from my experience by the time I was done mucking about getting those wobbly panels fitting perfectly, and stitched, and the whole business symetrical, true and fair, an so on, it would have been just as easy to frame in the first place. I prefer framed because it gives you something solid to work with.

L.W. Baxter
12-03-2004, 07:26 PM
It seems to me that the principal advantage of the S&G designs is that the panel shapes are provided by the designer. Time spent building a model and planking it could be time spent framing. Plus, framing is fun, and filleting epoxy is not.


Mike Vogdes
12-03-2004, 09:33 PM
I hear what your saying, it is a pain allways checking to make sure your true, fair and braced properly, but if your diligent you will have a nice looking hull when finished.
I agree framing is more enjoyable than fileting but it does become a little easier with practice.

Cuyahoga Chuck
12-04-2004, 12:33 AM
It's doable but why go half way. There are plenty of S&G designs that do away with framing and use precise plywood bulkheads for a modern monocoque type of construction. You get light weight and clean open interiors that don't trap moisture in every corner.
Devlin knows his business but suggesting that anyone can do what he does without climbing the learning curve first is a stretch.

Bill Childs
12-05-2004, 03:41 AM
I built a few sniff-n-glue boats about 20 years ago to see what all the fuss was about. They turned out ok but I'm wondering why anyone would rather go that route than simply shaping and fastening wood. Maybe the appearance of simplicity is the attraction or the notion that you don't need accurate joints to pull it off. I found the procedure not at all rewarding. Sure ya get a boat when all the work is finally over with but enjoying the building process is just as important to me.