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Protecting Your Boat From Winter Elements

Almost everyone agrees that protecting a boat from winter weather is a good idea. Drive by any boatyard during the winter season and you will see row upon row of cocooned boats in shrink-wrap or covered by tarps. A winter cover was not high on our list for High Life, our 36-foot trawler, since my wife and I took her south on extended cruises for the first five years we had her. We live in the Chesapeake Bay area with fairly mild winters so recently High Life has been laid up in her slip at our yacht club.

The first winter we stayed in the bay we had to consider a storage strategy to protect the boat. Shrink-wrap is a turn-key operation with almost all the work done by the wrap crew. Depending on your location and who does the work, a winter shrink-wrap can run between $15 to $25 per foot for a large boat with a radar arch or flybridge.
Probably the most appealing aspect of the shrink-wrap process is that someone else struggles with making and installing the cover. We have seen boaters remove small, simple shrink-wrap covers and use them again. However, large covers are usually a one-time shot, but there is no need to lug the bulky cover and frame to and from the boat and to find a place to store it when not in use.
We asked a local canvas shop that did most of the canvas work on our boat for a bid on a winter cover. Their busy season was over and they said they could give us a good deal and help install it if we ordered it right then. We agreed. The price, $3,300, seemed reasonable for a complete cover using WeatherMax, a polyester fabric that is UV resistant for long-term color and strength retention and has excellent breathability and abrasion resistance.
Because of its large size, the cover was designed in two sections with zipper doors at the three entry gates in the handrail. The boat already had rail covers with snaps below the rubrail, so the winter cover was designed to use them. This made installing the cover while the boat was stored in the water much easier.
To simplify the design of the cover and to cut costs, it was made to fit over the boat with the mast down. That way it was easier to make with less openings for the mast and its rigging and their potential leaks. In the stern the cover divides into two sections that fit around the mast at the radar and is joined by a zipper. To protect the varnish on the handrail from chafe, a strip of soft material was sewn inside the cover at rail height around the entire boat.
After getting the final measurements from the canvas shop we built the simple 2-by-4 backbone frame in four sections joined together with long all-purpose screws. These sections run from the bow up and over the flybridge. At the aft end of the flybridge the frame angles down to rest on the mast just before the radar dome. The backbone is 1-1/2 inches shorter than required so the cover can be snapped in place without a lot of tension. When the cover is secure the backbone is raised from inside and 2-by-4 blocks are placed under the backbone legs to raise the frame and tighten the cover.
We had planned to use wood furring to make ribs to support the cover and center the backbone, but the canvas installer recommended using 1/8-inch nylon line instead. The line is secured to the handrail looped over the backbone and then across the boat to the other handrail. Once pulled tight, the line centers the backbone and supports the cover at the same time. We placed the line every couple of feet from the bow to stern.
That first winter, the canvas installer helped put on the cover since he had to install the snaps on the skirt of the cover so they matched the snaps already on the hull. Every winter since then we install it ourselves. We choose a day with predicted light wind and get to work early since morning is usually the calmest time of day. The cover isn't heavy to handle, but it's bulky. If it was designed as one piece, I don't see how we could have handled it.
Since there's almost always a bit of wind, we install the cover on the upwind section of the boat first so the wind will push the cover on to the frame, rather than blowing under the cover and lifting it off the boat. The cover is much easier to haul up and over the backbone if left folded. Using the wind condition as a guide, we first snap on the windward section of the cover to prevent the wind from getting under it.
Since the cover is not tight you can reach around outside the cover and place the female part of the snap over the stud on the hull. A snap that won't completely seat can be snapped home with a light tap of a hammer. When the snaps on the windward side are secured we work on the other side.
The two halves zip together and if there is any wind at all it tends to help push the cover over the backbone since the covered end of the boat breaks the wind as you roll out the second section of the cover.
After two seasons the cover shows little wear. The winter of 2009-10 was a real test since we had several winter storms with heavy snow and winds gusting to over 40 knots. That's a real stress test for any winter cover.
After the first year, a few modifications made it even better. We had the canvas shop install storm flaps over the door zippers since they leaked in heavy rain. And we had additional vents placed at the top of the cover to allow for more ventilation. We discovered a condensation problem under the cover in the spring when the cabin house cooled off at night but the air warmed up fast under the cover as soon as the sun came out. To solve that issue we installed an inexpensive box fan at the bow and connected it to a timer. Running the fan a couple of hours a day in the spring moved enough air through the cover to stop this problem.
As investments go, we think a custom cover is a winner. An additional advantage is that there's plenty of headroom underneath the cover so we can get a head start on spring commissioning projects without worrying about the weather.