Was thinking about getting rid of the panel joiners and instead making a glued lap joint for sleekness and weight reduction on the weekender. From what I have read in "How to build glued lap-stake wooden boats"
the lap joint is stonger than the rest of the ply if done properly. Does anyone have any experience with this?
I've done several glued lap builds and designed a few as well. It's an efficient method for a lapped build and watertight too.
It would be difficult to do on a Weekender as you don't have enough "molds" to line off your planks, but you could build some if you wanted.
If you were going to build in this method, then the slab sided chine hull of Weekender makes all the laps the same, with no bevels required, except the gains on the hood ends of the planks. This generally produces an odd looking lapped hull. Lapped hulls are typically round bilged. You could add considerable roundness to the topsides without terribly affecting things. In fact a common radius would also keep the bevels nearly identical. If I were doing something like this, I'd be inclined to increase form stability aft and possibly displacement there as well. Maybe a slight amount of tumblehome at the transom, just for looks too. Sailing qualities wouldn't be affected much except when well heeled over, unless the bottom was also lapped.
I think John means simple scarf joints here, not planking. In that case you can join the bottom, side panels etc this way. It is strong and works well, but you won't be saving much weight in the over all build of the boat. It is cleaner and neater for sure but more complicated as well. Go for it if you like.
I used plywood butt joints on my cs 17. It is easier than scarfing to me and they work fine. I coated the two pieces of wood with epoxy at the joint. Work on a sheet of thick constroction plastic as epoxy doestn't stick to it. Put 3 layers of four ounce cloth over the joint. The first was 6 inches wide, the second was 5 inches wide, and the third was 3 inches wide. Squegee out any air bubbles. I covered the joint with a piece of construction plastic and covered that with a piece of scrap ply and piled bricks on to keep the joint weighted while the epoxy set. After it sets but before it is too hard uncover and scrape the edges of the tape with a cabinet scraper to smooth. This will save you sanding time later. Redo your weight until the joint has thoroughly cured. Turn the wood over and put 3 more strips of glass cloth on the other side the same way. This will give you a very strong joint.
I am building the Triad and used plywood butt joints to join the hull bottom and 3 deck pieces. I planed off almost the entire top layer (each side) of the plywood before applying the glass and epoxy. I used 2 layers of 6oz glass. The wood was 3/8" marine ply. The recessing of the joined edges was a suggestion from Paul Riccelli. It saved a lot of fairing later to make the bump disappear.
If I had to do it again I would probably join the deck pieces with the 1x3 wood backing pieces, as the plans called for, and the bottom, as I did, a butt joint. On the deck pieces the wood backing/joining is out of sight on the bottom side of the deck. The butt joints seem very strong but I worry about the epoxy cracking because it is very ridged after totally cured. I may be worrying needlessly but the two front joints on the deck are only 9" wide with one of the joint sides supported entirely by the front bulkhead and the other side not supported at all but in a spot where I can anticipate people stepping to get into and out of the boat. The deck on the Triad has a curve, from front to back, so there is also a small bit of compression stress to the front joints.