The Nickajack Glideboat Project is a design and fabrication project under-taken by John Hughes (Email: n4yvt@arrl.net) to develop a light, stable, fast watercraft which can be portaged. The boat is designed to be propelled efficiently by either oars, paddles, or a small electric/gasoline motor.
This prototype watercraft's cross-section incorporates a water ballast chamber below the floor level which will be placed about 4-1/2 inches above the keel. The water ballast is intended to stabilize the watercraft when it is not in motion. As the craft begins to move forward the water ballast will naturally drain from a hole at the base of the transom. Preliminary tests indicate that about 3 knots is suffiecient to drain the 300 to 400 pounds of water in a minute or so. The craft's floor will have a forward vent tube to prevent formation of vacuum in the ballast chamber during drainage.
The purpose of the water ballast is to stabilize the boat's roll while motionless. As the water drains from the ballast chamber the boat should lift up in the water and the forces associated with forward motion will take over to stabilize the craft's roll while it is moving. After the craft's ballast is drained, the waterline profile of the boat is much narrower minimizing drag and permitting more speed. A quarter-turn ball valve will be included to retain or exclude water from the ballast chamber.
The shape of the proposed watercraft is based on a transportable canoe-like boat developed in upstate New York state's Adirondack Mountains in the mid-1800s. It is a light rowed watercraft which is faster than a canoe but just as light. The boats are still made in the Adirondack Mountains today but the construction methods have evolved over time. Originally the boats were made by attaching a series of curved spruce ribs to a keelboard and then planking the hull with carefully shaped 3/16” thick planks. Some present day Adirondack Guide Boats are still made using either of fiberglass or cedar strip construction. Our prototype will be made of 1/4” strips made from Paulownia wood which has very interesting characteristics. It is a very light and relatively strong wood resistant to rot that does not soak up undue amounts of epoxy resin, which will be used to cover the Glide Boat. According to Internet sources, it has been used in Formula racing boat hulls. It grows wild in wooded areas of East Tennessee where the prototype Nickajack Glide Boat is being built.
The preliminary contours of the boat were based on data taken from a book titled “The Adirondack Guide-Boat” written by Kenneth and Helen Durant. Meticulous measurements, made by a gentleman named John Gardner, were taken off an Adirondack Guide-Boat which is preserved in the “Adirondack Museum” at Blue Mountain Lake, New York. The guideboat was named the 'Virginia'. That water craft provided the basic outline for the “Nickajack Glide Boat”.
The contours of the 16' long 'Virginia' were transferred into a spreadsheet and translated into a 3D coordinate system as a points. The point cloud was then read into a 3D parametric CAD program (VARKON, open source Linux software)<
and parametric 3D surfaces were modeled to approximate the 'Virginia' contours. The keel region of the 3D model was then modified to
accomodate the water ballast and floor additions. The VARKON plot below shows the final contours. Conventional 2D CAD drawings were then generated from
the VARKON 3D model and further detailed using another Linux 2D CAD program (QCad).
Currently a prototype boat is under construction. The hull has been completed and the exterior surface has been fiberglassed. The floor and interior fiberglass will be added this spring when the weather warms up. There are no present plans to market the watercraft although any suggestions from readers are welcome. I'm planning on launching the prototype this summer. If the boat works as intended, 2 more Nickajack Glideboats will be built for my grandchildern. They have asked for a 14 foot version so I will be going through another design cycle before that happens.