John DeChant and Jack Davidson's latest boatbuilding effort exhibits the best of what amateur boatbuilding is all about. They not only designed and built the boat themselves, they developed an innovative construction method to do it. John and Jack designed FROG BOAT to achieve a lightweight, high volume, stable, exploration boat. It would be powered with a small gasoline engine or an electric motor. It also needed to be easily paddled to sneak up on fish and wildlife. It had to be light enough for car-topping. The design took on the name of frog boat since it would live both in and out of the water. The name stuck.
To meet their design criteria, they developed an innovative building technique based on a wooden frame, foam and plywood sandwich. Construction began by setting up molds over which they built a fir and ash framework for the boat. To create the bottom, they used 1/8” mahogany plywood, ¾” builders foam (the pink stuff), and another layer of 1/8” ply. They bonded the plywood to the frames with epoxy and to the foam with waterproof mastic that is specifically intended for bonding foam to wood. The sides of the boat are covered with plywood on the outside of the foam only.
The transom is lightened ¾” plywood with laminations of 1/8” mahogany on both sides, making the overall thickness 1”. The stem is ash and fir. The breast hook and quarter knees are poplar plated with 1/8” aluminum scuff plates that prevent damage when the boat is being handled upside down on rough ground or concrete launching ramps. The shear strake, rub rails, and keel are ash. Glass tape strengthened the chines inside and out as well as all other seams in the boat. The entire boat is sheathed, inside and out, with 6 oz. glass cloth set in epoxy. After construction, the boat was finished with several coats of Pettit Easypoxy™ paint.
They are very pleased with their results . The boat turned out to be quite robust and extremely rigid in all directions. A proposed center thwart for side-to-side stiffness was totally unnecessary. The ample beam and depth translated to a shallow draft (3-4” with 600 pounds aboard). The safe load carrying capacity will be high and certainly enough for two people and a bunch of camping and fishing gear.
With a small motor pushing it, the boat is as fast as they want it to be. It's quite stable. Attempts to ship water over the sides by aggressively rolling the boat from side to side while under way did not bring one drop of water aboard.
The foam sandwich construction method rewarded them with the bonus of having no interior frames. There is nothing to trap dirt, water, dead minnows or people's feet. The interior of the boat, with the exception of the seat verticals, is perfectly smooth.
The boat paddles quite well considering its size and shape. It tracks beautifully yet surprised John and Jack by turning quite readily.
The weight of 93 pounds is a bit more than they had hoped for. In spite of that, the boat is still easily car-topped by two people.
The project was quite time consuming and sometimes frustrating, but they got the job done. Fortunately, Jack is a great engineer / draftsman / problem solver and through his efforts they were able to transfer many of their ideas from brain to paper to boat.
Although the boat's name is FROG BOAT, it could also be called ACCOMPLISHMENT as a testimony to John and Jack's ability to design and build a boat while solving the many problems of an innovative construction technique.
If anyone has questions or comments they'd like to direct to John or Jack, they can contact them at 1177 Woodlawn Ave, Girard, OH 44420 or at jedechant1@aol.com .