Wednesday, July 17, 2019

Paint, centerboard and rudder

Once again, nail setting, puttying and sanding was followed by two epoxy coats on the decking. Three coats of white topside enamel later, the boat is gleaming and bright. I used a little paintable caulk to fill the edges of the decking purely for cosmetic reasons (the joints are solidly glued withe epoxy compound so no leaks are possible). I will need to sand the puttied holes and touch up the sheer strake paint on the outside.

For the centerboard and the rudder I calculated I needed about 6 kg (13.2 lbs) of lead weighting. I opted for lead shot which will be sandwiched between the two outer layers of each, placed in voids cut in the middle layer: a square of 30 cm a side for the CB (for 4.5 kg) and a 8.5 cm radius circle for the rudder (for 1.5 kg). The third photo shows the CB void packed with lead. In calculating the sizes I reckoned on a specific gravity of 11 for lead and a packing ratio of 78% for the little spheres (i.e. the voids between the little balls of lead will be about 22% of the space). I was a bit off and I had a little lead left over.

The fourth photo shows the top layer of the CB laid on with nails  and epoxy and weighed down with stones and a bag of cement. Nothing but the latest technology!

The last photo shows the two main parts of the rudder laminated from three layers. One of them is the pivoting bottom with its own lead ballast inside. I will need to put on the jaws and make a tiller. Both rudder and CB will be shaped hydrodynamically and finished with epoxy and varnish. More in the next post,