The original concept was to construct a fiberglass box that would fit into the recessed portion of the aft bulkhead of the anchorwell.
One issue that became apparent right away was that if the top of the fiberglass box was the same height as the surrounding structure the top of the windlass would block the anchorwell hatch from closing. The first modification was to drop the top of the fiberglass box to provide clearence. The finished dimensions were calculated to be 9.5″ wide x 6″ deep x 11″ tall (I need to double check the width). Since I had the “finished dimesions, I decided to construct a female mold and work from that. I estimated that the box should be alternating layers of fiberglass cloth and bi-axel cloth. To save some money I used MAS epoxy resin which costs slightly less than West Systems.
I used 3/4″ birch plywood from Home Depot for the mold. The sections were clamped together and the inside coated with a heavy layer of Johnson’s paste wax. I alternated layers using 8 oz fiberglass cloth and the biaxial cloth (medium weight).
After every two layers of cloth I would add a layer of 6″ wide fiberglass cloth tape to build up more strength in the sides of the box. I don’t remember the total numbers of layers but it was probably around twelve layers. The box is a little over 5/16″ thick. Probably more like 3/8″ on the face.
The top piece was constructed using 1/4″ plywood cut to size. I then laid up alternating layers of 8 oz. fiberglass cloth and biaxial cloth (medium weight) until the whole top was 3/4″ thick. I use four 1/4″ x 2″ stainless steel flat head machine screws (holes were countersunk and with 2 layers of 8 oz. fiberglass cloth (saturatured in epoxy resin) between the top and the box) to attach the top to the box.
Once the resin had setup, I trimmed the edges with a tablesaw. I use the tablesaw to cut a 1/4″ groove (1/4″ deep) in all four edges to remove the plywood. I filled the groove using epoxy resin and Colloidal Silica. Using the template that came with the windlass. I drilled the holes for the mounting bolts and used a hole saw to cut the two holes for the rode and the motor shaft.
The flange I decided to add to the port side was laid up in the same way using two 1″ x 4″ x 9″ nailed together to form an “L”. Again, this ended up being about 5/16″ thick. I sanded the two surfaces that would be mated together with 50 grit sandpaper. I drilled two 1/4″ holes for a pair of stainless steel 1/4″ x 1″ flat head machine screws and nuts. I used two pieces of 8 oz. cloth (saturatured in epoxy resin) between the box and the flange. Once, I tightened down the screws, I cleaned up the resin that was forced out. My orginal plan was to remove these screws after the resin had setup, but with the resin getting into the threads, I decided that I would just leave the screws in place.
I made a fairing compound using MAS epoxy resin and Phenolic Micro Balloons. This needs to be very thick (like peanut butter). I used a plastic spreader from Home Depot. Between each coat I would sand everything smooth using 150 grit sandpaper and a palm sander.
Once I had a smooth surface. I wiped everything down repeatedly with acetone. I then used a Preval
disposable paint sprayer to spray 2 layers of gelcoat on the inside and outside of the box. The gelcoat I used was Finish Gel Coat – Waxed Non-Lam, Pint, White (#3745478) from West Marine.
The color is not even close to my hull color and is a very bright white. I was not happy with the color, but decided that it was in the anchorwell so no one would ever see it. Now that it’s installed, I don’t even notice the color. I did thin the gelcoat with about 20 % acetone. The Preval sprayed did not work all that great but the box is small and it got the job done. I was mixing about 4 ounces of gelcoat at a time. I would sand between each coat using 220 grit sandpaper. Then I would wash down the box with soap/water and finially wipe it with acetone to make sure I had removed any wax.
The box was mounted in the anchorwell using 1/4″ stainless
Story by Rick Johnson
Category: Tech Talk