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10 Ways Winter Can Wreak Havoc with Your Boat


These winter gotchas don’t just happen where there is snow.

Snow accumulating in the cockpit can put above-waterline fittings below the waterline, with the inevitable result

Download the BoatUS Winterizing Guide for an in-depth look at best practices for keeping your boat safe over the cold months of winter.

Winter may not be out to get you, but it sure seems to be after your boat. Reading through 10 years’ worth of winterizing claims, the Seaworthy editors were astonished at how many ways cold weather and ice can damage something made of metal, plastic, and fiberglass that lives its life out in the elements. The single most common winterizing mistake is not getting all the water out of — or enough antifreeze into — the engine, which is why our new winterizing brochure focuses on making sure you don’t end up with a cracked engine block or manifold. But there are a lot of other ways winter can get your boat, most of which could be avoided with good winterizing practices. Engine damage aside, these are the 10 most common winter “gotchas” and how to avoid them.

The Slip And Slide

If jack stands are not set upproperly, they can end up shifting out from under the hull and dumping your boat in the middle of the winter. Jack stands should be placed as far out from the boat as practical to support the boat in high winds, with at least three per side for boats over 26 feet and additional supports at overhangs. The weight of the boat can easily force a jack stand base deep into mud, sand, or asphalt. Even clay that seems brick hard can become a quagmire in heavy spring rains, allowing stands to loosen, shift, and spill the boat. Placing a piece of plywood under each base and using safety chains to connect the stands will help to stabilize the support upon which your boat rests.

The Tattered Tarp

Covering your boat in the winter benefits it by protecting gelcoat, preventing snow and ice accumulation, and keeping water from pooling on the decks. More frugal skippers seem to think that a few tarps stitched together with a spiderweb of lines qualify for winter duty. In the first serious storm, these often end up shredded, and in their death throes they deposit large amounts of snow and ice into the boat they are supposed to be protecting. If you’re going to cover the boat, use a custom cover or shrinkwrap it, but either way make sure there’s lots of ventilation to prevent mold from taking over down below.

The Shrinkwrap Smolder

Stanchions are not meant to take the weight of snow and ice that can accumulate on a cover. And, as this photo shows, neither are the decks. This stanchion drove right through the deck on this 26-foot sailboat when the ice overloaded the stanchion and the deck beneath it. If you decide to cover the boat, do yourself — and your boat — a favor, and build a proper frame.

The Cheater Heater

Our claim files show that “winterizing” a boat by leaving a heater running onboard is just not a good idea. First, your engine is least likely to be protected when it most needs it — in a big storm when the temperature plummets and the power goes out. Second, every winter we see fires from heaters, plugs, and cords where heaters were left running on unattended boats. Unless you are located in Hawaii or the Florida Keys, we recommend winterizing your engine if you will be laying up the boat for even a few weeks to minimize the chances that a sudden freeze will put it out of commission next season.

The Water Trap

Many places on boats have small holes so that water can drain out — boats are wet places after all. If those drains get plugged, it doesn’t matter that much in the summer, though corrosion may follow in the long run. But if they are plugged in the winter, the water inside will expand as it freezes and could do serious damage. Check drain holes in stanchion bases, mast steps, live wells, locker lips, and anywhere else you have found them to make sure they are not clogged and no water has accumulated. If some areas are not draining adequately, consider adding a few more drain holes to facilitate the process.

The Soggy Bottom

When you haul your boat for the fall and you notice that the rudder is dripping water a few days after it has been on the hard, or a keel has a blister that develops in the warm sunshine and recedes at night, the chances are you have water trapped in the rudder or the keel. If you leave it that way through the winter, it will freeze, and may damage the fiberglass. Before the first freeze, you need to get that water out. Large blisters can be punctured and drained. On rudders, you may need to drill a hole at the bottom of the leading edge of the rudder. If you leave it open through the winter, that should help the laminate dry out, and you’ll have an easier time filling and patching it in the spring. Before you put your baby back in the water, though, you’ll want to figure out where that water came from and how to keep it from getting into the rudder or keel again next season.

The Snow Job

If you’re going to leave your boat in the water, you need to make sure that snow and ice do not accumulate in the cockpit over the winter. Not only can the weight force the boat low enough in the water that it can backfill and sink, but the thaw and freeze cycle can create a plug of ice that slows drainage through the scuppers. It’s best to cover a boat that’s to be left in a slip, but if that’s not possible, make sure to get to the marina after every storm to clear out the ice and snow and make sure scuppers are not blocked.

The Buddy Special

A lot of the freezing claims we get start with an owner calling and saying, “I let my buddy winterize the boat.” The rest of the news is never good and most often involves cracked engine blocks spewing brown bubbles or muddy-looking oil. Winterizing is not rocket science, but forgetting even one detail, or doing it incorrectly, can spell disaster for the boat — and your friendship — next spring. If you’re not comfortable winterizing your boat, have an experienced professional do it.

The He Said/She Said

And if you are going to have an experienced professional do it, make sure to get everything in writing. The term “winterizing” is not universal and your idea and theirs may not be the same. Will they just run antifreeze through the engine, or will they service the AC and refrigeration units, too? Spell out what will be done so, if anything goes wrong, it’s clear who is responsible.

Beth Leonard

Contributor, BoatUS Magazine