Building the Rushton Catboat

Centerboard and rudder

The catboat's centerboard and rudder are both made of white oak. Over all it was relatively straightforward. Perhaps the only thing of interest to readers might be my use of melted lead to provide negative buoyancy for each. I keep a scrap bucket of lead, most of which came from replacing nineteenth century plumbing in my house, and in the past I have made lofting weights and other odd items. Lead, of course, is dangerous material and when melting it I always work outside and wear my respirator. For both the rudder and centerboard I cut holes large enough to hold a few pounds of lead and drove copper nails into the sides of the cuts, leaving them exposed, giving something for the lead to grab on to.

I melted the lead over an electric element in a simple aluminum pot. This is good enough to melt lead eventually, but I hurried the process along by using my plumbing torch and playing the flame on the lead.

I first taped aluminum foil across the bottoms of the holes and then propped the centerboard and rudder on bricks such that a bricked backed up the foil. I stacked more bricks on top to hold it all steady.

When the lead was melted I carefully poured it in to the cavity, making sure to fill it over the brim slightly. The most dangerous thing pouring lead is any stray moisture, as the hot lead with vaporize the water and create a small steam explosion, throwing molten lead. I made sure that everything was dry, working on a brick patio so that the whole area was non-combustible. Did I mention safety glasses and gloves?

Lead cools within an hour and it shapes easily with a handplane.

After smoothing it off I applied a layer of fiberglass to the centerboard, but the rudder just got putty and paint. The worst thing that can happen to a wooden centerboard is for it to warp (especially if that locks it inside the trunk) so fiberglassing it seemed as easy way to render it completely waterproof and stable. I had originally thought of using steel plate for a centerboard but my client plans on sailing this boat in a shallow lake with lots of underwater obstructions. He felt that a centerboard that would "give" more easily to obstructions would be the best option. The amount of lead I put in the board will definitely sink it, but it won't be the immoveable object that a steel board would.

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