Friday, December 30, 2011

Port lights

I have seven port lights on the boat and all of them are fixed, non opening lights. The reason I decided to use fixed lights were for two reasons. Reason number one was the designer of the boat was not to keen on opening lights given how close to the water line the port lights would be ( about 3' amid ship, 4.5' on the forward light), and the other reason was for cost savings. The cost savings are a result of me fabricating the port lights and not buying commercially made lights. Including the 1/2" tempered glass, gasket material, and screws, I have less than $250.00 in building all seven port lights. This small amount of money is encouraging, but hopefully is not something that will bite me in the ass years down the road once we start using the boat.

My primary concern with fixed port lights is of me having cut off ventilation to the cabin area of the boat. Because the port lights are fixed, I had to pay closer attention to how I was going to keep the air fresh and flowing in to the cabins. The kids cabin has a 20" x 20" ocean hatch along with two 5" dorade style vents. The hatch will be open when possible, and the dorade style vents will be operable more often that not. The thing I like about the dorade/cowl style vent is that we can leave them open while we are not on the boat so fresh air continues to circulate. The kids cabin also has 12 volt fans. The master cabin has two 6" dorade/cowl style vents and two 4" dorade/cowl style vents. The master cabin also has 12 volt fans. The lower cabin area has a dedicated, marine style, 12,000 btu air conditioning unit.

I recessed the port lights in to the hull 5 1/2" which made the lights flush with the interior trim. I really like the the way the recessed light looks on the exterior hull, and I also like the flush look of the interior trim of the light. The recess of the port light was fabricated using all stainless steel. Given that I was going to bolt the glass to the hull using a clamp ring, and how difficult it was going to be to not mar the metal flange, stainless was the only material I could use to insure that no rust stains would originate from the port light. With the flange of the port light so close to the interior trim, having the metal sweat was another big concern for me. I painted the flange with insulating paint, and also installed a closed cell gasket on the interior face of the flange. The wood trim rings then covers the gasket and flange, so all you see is glass and wood.

To give the exterior recess a more refined look, I flared the recess out 7 degrees. The 7 degree flare made fabricating the recess spigot a bit of a challenge, but once I figured out the cuts, the job was fairly simple. The port light recess spigot consists of five parts: the flange, the two end piece's and the two center piece's. The two end piece's are what make the 7 degree flare, and in order to help the weld up go easier, I bent the end piece's on a jig I built to work on my log splitter. I also built a jig for welding the spigots so all the spigots would be identical. All of this work happened a few years ago, so all of the above post is a re cap.

The current job regarding the port lights was getting the glass installed. All through the port light building process, I had made and save templates of the various parts. Having the templates in the shop has saved me the time and hassle of having to re figure everything and allows me to easily fabricate parts like the 14 additional gaskets I had to cut to get the glass installed.

Each piece of 1/2" tempered glass is held in place by a stainless steel clamp ring. After I fabricated the clamp rings, I sand blasted them to help the paint stick to the rings. The ring is bolted to the spigot flange using (14) 1/4" stainless machine screws and nyloc nuts. There is an 1/8" closed cell foam gasket glued to the flange using contact cement, the glass, and then the stainless clamp ring with another 1/8" closed cell foam gasket glued to the clamp ring. So, basically, if you can envision a glass sandwich of gasket flange, glass, and gasket clamp ring, you can sort of see my design. I did not bolt any of the port lights to any of the interior timber framing, rather all the lights are bolted to the flange only. In my eyes, this was critical to not allow any wood movement to cause nuts and bolts to loosen. In the bathroom, I did use four longer bolts to bolt the trim ring to the port light flange as there was no other way to fasten the wooden trim ring.

Installing the glass was a two person job. One person on the outside dealing with the parts install, and one on the inside holding the nyloc nuts so the screws could be torqued. Even though I used a jig to weld the spigots together, the flange is not perfectly flat. The lack of flatness is not hatefull, maybe .080 across the length of the 19" flange, but it's possible presence gave me enough concern to be careful in how much torque I used while tightening the screws. I torqued the screws enough to start compressing the gaskets, and no more. The nylon nuts will prevent the screws from loosening up. While the flatness of the flange is really not an issue, I did not want to get all gorilla on the screws and risk cracking the glass. Because of the outward camber of the glass, I applied a little bit of contact cement to the glass and the flange gasket prior to installing the glass. I then pressed the glass to the gasket to hold it in place while I positioned the clamp ring and pushed the screws through. The gap between the clamp ring and the spigots sides is a respectable 1/8" - 3/16", which I will calk later, once I figure out what kind of caulk I'm going to use. A clear caulk would probably work, but I'm going to look in to tinting some caulk the same color as my paint. I haven't decided if I will caulk the glass to clamp ring joint yet. I feel very good that these lights will not leak and will be robust enough for off shore use. To test the quality of the seal we made, I had my son inside the boat and I used the shop air compressor to blast air at the port light from outside the boat. Using a smoking match, we could see no signs of air getting past the seal we made.

Because of how the lights are framed, I decided to paint the spigots before installing the glass. I gave each spigot a good scuffing, and repaired some dings I made from carelessly throwing debris out of the port light opening. I'm using PPG's industrial line of paints on the boat and have decided to use an acrylic urethane. The urethane is a high gloss with good toughness ratings and abrasion resistance. The thing I like about this paint is the ability to be able to get back in to the paint for repairs. I really would have preferred to have the whole hull painted, but I'm not ready for that stage yet, and won't be until late spring or early summer. Seeing the first bit of shiny paint on the boat was a big time boost to my morale, and has really got me motivated to get to the stage of being able to top coat the whole hull. Because I painted the spigots before the hull, I have a parting line to deal with around each port light. For painting,I taped the light off 1" away from the spigot. When I paint the hull, I'll wet sand the parting line I just created flush with the primer, then tape back towards the spigot 3/8" or so. I'll then have to wet sand that now new parting line flush with the top coat I just applied and buff. I'll have more parting lines to deal with due to the way I intend to paint the hull. If I can get another person to help with the spraying, I might get away with no parting lines other than the port lights.

All the port light glass is now installed, so I can now permanently install the wood interior trim rings and give them a coat of urethane. Now that the glass is installed, the difference in sound is amazing. I can no longer hear the radio that plays in the shop, and my son and I had to almost shout to communicate with him on the inside of the boat, and me on the outside. I'm happy with the way the port light project turned out, and I'm very happy to have another big job checked off of my list.


  1. Very nice tutorial on fixed portlights Conall.

    Happy New Year to everybody there.

    Rick & Lori

  2. Thanks Rick. Happy/warm new year to both of you too.