Archives pour mai, 2014

Question: Sealing Boat Windows

One of the sailors prepping for this year’s Singlehanded Transpac recently asked me how the windows on Idefix held up. As you might recall from this post, in preparing for the 2012 SHTP I had replaced the old, leaky, cracking and hazy windows with new ones. I didn’t go into much detail about how I installed them, and I hadn’t followed up on how they held up, so it’s probably time I answered that.

Just one word: plastics

acrylic_sheetsFirst of all, I used acrylic for the windows. Acrylic is also known as plexiglas. The other choices would be polycarbonate (sometimes referred to as Lexan) and glass. Glass is an obvious no-go for me because it’s heavy, fragile, expensive, and hard to cut and shape. Polycarbonate is frequently used to make bulletproof windows, fighter pilot canopies, motorcycle helmet visors, and other impact-resistant applications, so one might think it would be a good choice for a boat window. But it has some significant drawbacks. For one it scratches much more easily than acrylic. It is also way more flexible for the same thickness. And more expensive. Finally it is very hard to find it in the right thickness, and colors are very limited.

Acrylic, on the other hand, is quite stiff and scratch resistant. The downside is it tends to crack if it is improperly stressed. In the end, I chose it for the simple reason that it was cheaper, easy to cut myself, which is why all the boat manufacturers use it for windows and hatches.


Cutting the acrylic to shape was pretty easy. It comes with a protective layer on each side that you peel away before installation. I removed the existing windows and used them as templates, tracing their outline on the protective sheeting. I then cut the acrylic using a bandsaw, and smoothed the edges with a belt sander.

The goop

795After choosing the material, I had to choose a way to fasten it to the boat. The Olson’s original acrylic windows were fastened with screws every 6 to 12 inches, and many had cracks radiating from them. The reason they crack is that the windows expand and contract much more than the fiberglass does with changes in temperature, leading to loads at the screws. I didn’t like the idea of drilling holes into my spiffy new windows, so I decided to forgo the screws, and just glue them on. Many boatyards take this approach. For adhesive, I did a bit of research on boat forums and chose Dow 795, which is allegedly used for gluing windows into skyscrapers. I’ve been told that Sikaflex 295 UV will work as well.


First of all, I had to meticulously clean up the area around the old windows. I hate leaky boats, and I wanted a perfect seal. This required a fair bit of peeling off old 4200 (yuck), scraping it off with razor blades, and sanding whatever was left. Then I rubbed the bond surface with acetone and wiped it dry. When all was ready, I cut the protective sheeting on the acrylic with an exacto knife in such a way as to expose only the bond area, leaving the inside window protected. I applied a steady bead of 795 all around the window. Too little and it will leave voids, but too much and it will ooze all over the place. Then I lined up the window and pressed it into place. The hardest part is to find a way to apply pressure to the window to keep it lined up and in place while the silicone cures. This involved a clever arrangement of 2x4s against the lifelines, but the forward windows were tricky and I ended up holding them in place manually for a little bit, then leaving them to their own devices. The cure time for 795 is supposedly three weeks, and I was a little worried because we had our usual Seattle cold and humid weather, and I even took the boat sailing a few times, but eventually everything hardened up nicely and the windows stayed put.

New hotness.

New hotness.

Ten thousand miles later…

As it turns out, the windows worked perfectly. There were no leaks for my whole trip to Australia, and the windows were nice and solid. Either at the dock or on the trip, one side of the boat was a little more exposed to sunlight, and one of the windows ended up getting a little bit of UV crazing, but other than that they looked as good as new.

And finally, a question of my own. What do you call the windows on a boat? Portholes? What if they don’t open?

Farr 40 North American Championships

I sailed on Huckleberry 3 in the Farr 40 North American championships in Long Beach two weeks ago, and it was a fun four days of sailing, but very tough racing for us. The level of competition is incredibly fierce, and a couple errors on the first (windy) day cost us multiple places in every race. A jib sheet I’d improperly left on the winch in a tack got seriously fouled and took ten or fifteen ugly seconds to clean up. In the last race a bad hoist wrapped the kite and we watched four or five boats sail past us as we struggled to clean it up. These are mistakes that can be made up for in handicap races, but are unforgivable at this level of one-design competition. We ended the day pretty frustrated, as we’d been in the middle of the fleet before screwing things up.

The breeze was lighter on the second day and we brought our A game. Our boat handling was better than it had ever been, and our maneuvers this time were flawless. But the other boats had improved as well, and this time we found our boat speed to be just plain lacking. We ended up at the tail of the fleet the whole day, and the next two days as well.

This was a pretty frustrating exercise, but I learned a lot, made some new friends, and my arms and shoulders have doubled in size from all the pulling lines and grinding winches! Check out the photos from the event on Joysailing’s page.

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