When the high summer sun brings on the sultry days of July and August, many people head for water to obtain relief from the heat — and the Mother Earth News research staff members are no exception. The lure of the 11-acre lake at MOTHER's Eco-Village is a great temptation at this time of year. And as a result, our flotilla of unique pond craft has grown — from the sailing and trolling canoe we reported on in our last issue — to include a pontoon boat that can be set up for a leisurely pedal-powered cruise or for prowling remote coves for bass.
In the spirit of "more from less," Dennis Burkholder and Robyn Bryan have developed a switchable flotation system to which many different frames and/or decks can be rigged. And though we've pictured three versions here including one- and two-seat pedal boats and a fishing platform equipped with an electric trolling motor-we believe that these possibilities will merely open the hatch to even more creative ideas from inventive readers!
Consequently, we're going to show you how Robyn and Dennis built their pontoons and then review the construction of one option: the one-person recumbent pedal frame. With that background, you should be able to adapt these designs to produce the pond vessel of your choice to suit your own needs.
To achieve sufficient buoyancy for two adults, Dennis and Robyn decided to fabricate pontoons with cores made of solid expanded polystyrene foam (also known as bead board), rather than attempt to adapt the PVC sewer pipe and foam-bead floats they used on the outrigger canoe. The skin for each unit consists of quarter-inch plywood sides, a 1 by 12 deck, and aluminum flashing undersides. These materials are waterproofed and made rigid with a layer of fiberglass cloth and resin.
Start by sawing a quarter-inch by 4-foot by 8-foot sheet of plywood into four 1-foot-wide strips and shaping them to the desired profile (for easy cruising over the bounding main) with a saber saw. Then screw the laminated boards to the edges of the 1 by 12 deck to close in three sides of each pontoon. Next, slice off 11½-inch widths from the bead board sheets with a sharp knife, and fill the inside of the hull with slabs of the material ... to a level about 1 inch short of the lip.
At this point, cut off three 11½-inch pieces of 1 by 4 for each float, slip these braces between the plywood sheets so that they're evenly spaced along the unit's length, and nail them in place. Now, fill the spaces between the 1 by 4s with sections of beadboard cut to size.
You can use the plywood walls as a template for trimming off the excess foam hanging out beyond the hull's profile. An electrically heated wire does the neatest and, quickest job, but a bit of persistence with a handsaw will also work.
Read more at http://www.motherearthnews.com/do-it-yourself/a-recumbent-pedal-pontoon-boat-zm0z10zhun.aspx