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Building a Seahood


I am building a seahood because I have decided to shorten the boom and use a midboom traveler over the companionway. Now is the time to build a seahood if I'm ever going to build one. The basic construction for this seahood is to mount rails on the cabin top on either side of the closed companionway hatch, and screw and glue two layers of 1/4 plywood over the existing hatch so the seahood forms the same curve as the hatch. Then I will remove the assembly and cover in glass and epoxy. When it is fully sanded and painted, I'll remount it over the hatch.

First, I cut clear basswood, two boards for each side forming two rails about 1-3/4" thick. I glued the boards together, staggered to take on the angle between the cabin top and the beveled side of the sliding hatch.

I attached the rails to each side of the hatch and then temporarily screwed them to the cabin top from underneath. Then I laid the first of two sheets of 1/4" plywood over the rails, glued with thickened epoxy. After about two hours the epoxy had kicked, I removed the screws, and laid the second sheet on top, also temporarily screwed. The plywood is held off the top of the hatch with a 1/4" shim.  Once the glue has fully cured, I will add an end cap at the aft end of the hood to support the shape of the hatch curve, then remove the hood and cover it with glass. Here is the seahood off the boat. I added fillets to all the inside joints in preparation for fiberglass.



After about an hour's work with a rasp, plane and some 40 grit sandpaper, the overall shape of the seahood began to emerge.




Today I added a second layer of 24 oz biax to the inside front and a third layer reinforcing the forward corners. After the biax dried, I fashioned a rear support /  dodger coaming and glued it in place under a strip of 24 oz biax and thickened epoxy. The combination will keep the rear edge from deforming and the coaming will create a watertight lip to attach the bottom of a dodger to.


After the coaming dried, I added the first of two layers of 16 oz cloth to the outside. The method I use to lay cloth is to first cut it to the size I need, and mark it so I can lay it down without a lot of messing with it. Then, I paint the surface with unthickened epoxy and wait for it to begin to kick. When the epoxy begins to gel, I lay out the cloth over the epoxy and smooth it gently with my hands to get out all the wrinkles and folds. Then, I  paint on more epoxy and use a spreader to move it evenly over the cloth to thoroughly saturate it but not flood it. While the epoxy is still chemically gelling. I lay on another layer: here is a picture of the second layer of 16 oz cloth.

Finally, as a top layer I added 6 oz cloth to the second layer as it began to firm up. In the 70 degree weather we are having I used West System with a fast hardener--had it been any warmer I would have used a slow hardener to give me enough pot time.

When everything hardened, I trimmed off the excess cloth around the bottom edge with a Japanese saw, and used a rasp and a palm sander to bring the glass down even with the frame.  Then,  I washed it down with water and a 3M scrub pad and filled the sides and about two inches along the top with epoxy thickened with microballons, a light sanding mix just to fill the weave of the cloth. I sanded the filled weave smooth and then painted the same area with unthickened epoxy to fill any slight irregularities. I will wet sand this when it dries and then paint the smoothed parameter with white SystemThree LPU. After that I will tackle the non-skid area.

This morning I wet sanded the "smooth" areas of the seahood and filled some small imperfections, correcting the fillet between the hood and the aft dodger splash rail which looked a little ragged. I used West System 410 Microlight for this work, mixed to a consistency thinner than you think it should be (It still dripped off the stirring stick), which helps it level and feather to a very fine edge.  I'll do a final sanding when the epoxy dries and add a first coat of paint later today.

Here is the seahood with a first coat of System Three LPU wet sanded. As you can see I sanded most of the paint away. I wanted to only fill the slight irregularities. Tomorrow I will spray a first and second coat. It doesn't look it from the photos, but the epoxy is baby butt smooth at this point.

Here is the first coat of System Three LPU sprayed. It's a little blotchy, which I have come to learn means I haven't thinned it enough. ST says to thin the paint (with water, of course) around 20 percent, but I find, maybe because of the sprayer I use, that I need to thin more like 50 percent. Today temps were around 65 or so in the shade, low humidity--perfect conditions for SystemThree LPU.

Here are some pictures of the second coat, with the paint thinned more than recommended. It is hard to tell but it covered and flowed better.


Here is the inside of the seahood painted out. Notice the two scuppers I cut with a rasp. These I coated with epoxy and will paint before installation.

Next, I tackled the nonskid area. I masked it off with Fineline tape and mixed up a combination of System Three Orcas White LPU and Interlux Intergrip non-skid additive. The directions called for mixing 6 to 8 ounces in one quart of paint so I reduced those percentages and mixed one ounce in 4 ounces of paint, followed by 2 ounces of water as a thinner. I used a 1/4" nap paint roller and even though the mixed paint was very thin it held the non-skid additive in solution and rolled on very nicely. Here are closer photos of the results.



When dry (about 30 minutes) I applied a second coat of the same proportions: 4 oz of paint, 2 oz of water and 1 oz of Intergrip, this time with 16 drops of crosslinker. The crosslinker makes the paint significantly harder and I don't want this nonskid to wear down. Here's what the second coat looks like:



Here are some shots of the seahood positioned in place on the cabin:


More coming on the dodger coamings. For more projects related to the exterior of the cabin, look here.



Copyright 2005 - 2014 by David Browne, all rights reserved, hosted in USA