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How to Build a Double Scull Shell

A scull is a long, narrow boat used for competitive rowing, with a shape inspired by kayaks and designed to create as little drag as possible when cutting through the water. The original sculls used wood throughout their construction, but modern day sculls consist entirely of man-made materials, such as fiberglass. This results in a process simple enough for any enthusiast rower to follow and requires tools commonly found in any home improvement store. Unlike a naturally constructed scull, molds made with synthetic materials are destroyed in the fabrication process, which makes this shell expensive to produce.

Things You'll Need

Boating foam
Serrated knife
gauge AWG stainless steel rod
Fiberglass sheets
Carbon fiber patches
Fine- and coarse-grit sandpaper
Full face mask
Goggles
Spray paint
Epoxy resin
Gel-coat

Instructions

- 1
  Measure and cut a length of boating foam equal to the desired length of the scull and lay it on a flat surface. Sculpt a rough outline of the scull from the foam with a serrated knife. Be careful not to remove too much of the foam as the process is irreversible. Finish the scull mold by melting the carved edges into curves with agauge AWG stainless steel rod connected at each end to a 12V/2A power supply to form a simple induction heater.
- 2
  Smooth the curves of the mold by hand with fine-grit sandpaper. An uneven surface will leave imperfections on the scull shell, which will increase the drag of the boat in the water and limit the rowers' performance. The foam will always appear fairly smooth to the eye so use touch and feel for any imperfections that need to be addressed.
- 3
  Wipe down the foam with a damp cloth then apply a layer of fiberglass to the mold. Use carbon fiber patches to seal any seams or tears that develop during this process then coat the entire fiberglass layer with a thin layer of epoxy glue. Repeat this process until the fiberglass is at least four sheets thick. Adding more sheets will increase the stability of the shell but make for a heavier boat.
- 4
  Put on a full face mask and goggles to avoid eye injury and inhalation of fiberglass particles. Smooth down the fiberglass shell with coarse-grit sandpaper. Finish the shell by applying spray paint over a single layer of gel-coat then leave the shell to set up in a well-ventilated area. Check the surface of the shell by touch once the finish is dry and fill in any imperfections with spray paint for light scratches; use gel-coat if any cracks appear.

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