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Oct. 4, 2021

Winter Boat Storage Myths Debunked

You want your boat well protected during the winter months, so don’t let these myths steer you in the wrong direction.


Those warm summer days are a thing of the past. And with winter closing in, we hope you’ve already checked out our How to Store Your Boat for the Winter blog. Winter boat storage is a critical consideration, because when spring rolls back around you’ll want to pull the cover off to find your beloved boat in tiptop condition.

There are a lot of theories about how to best store a boat for winter. Some are sound. Others, not so much. Beware of these winter boat storage myths that can lead you astray.


Myth: You should wrap the engine’s gearcase/lower unit with a plastic yard waste bag, then use duct tape to seal it off. This prevents water intrusion and weathering.

Fact: This does more harm than good because condensation can form under the plastic wrapping, causing water to collect in the lower unit. Then, freeze damage becomes a possibility. Outboards and sterndrive lower units should be tilted all the way down so they drain completely. They should be stored open to the air or protected by a cover that allows them to breathe. See How to Winterize Your Outboard if you have any questions about the best way to protect your engine through the offseason.


Myth: You can use household items such as mothballs, human hair and dryer sheets as repellents to keep rodents out of your boat, preventing them from chewing up seat cushions and wires.

Fact: While many people anecdotally report varying levels of short-term success using the repellents described above to keep rodents out of their boats, scientific studies haven’t proved their effectiveness. Most users agree that once the odor of these items dissipates, they have little to no effect.

Rodents have a vomeronasal organ (VNO) that detects pheromones, and researchers suspect they also use it to sense the presence of predators. The journal “Science” has reported that researchers from the Scripps Research Institute® have found that cotton balls laced with cat saliva, rat urine or snake skin essence activated the VNO in mice, and caused them to “cower in a corner.” There are several mouse-repelling products on the market that include one or more of these substances (such as urine from a bobcat, a major predator of mice in regions where bobcats are present). So, if you have a known rodent problem, these products hold much more promise than any fictitious fixes.

A mix of wintergreen oil, peppermint oil, chili, bergamot oil and geranium oil was tested in a study by researchers at Chulalongkorn University in Bangkok, Thailand, and was also found to have some level of deterrence. However, the longest time period observed was one week, so the jury’s still out on the long-term effect of wintergreen, et al., over the winter.

Another scientifically proven rodent repellent is eucalyptus oil. A study performed by researchers at Punjab Agricultural University in Ludhiana, India, found that rats were far less likely to eat food treated with eucalyptus. However, its effect deteriorated quickly, and weekly application was significantly less effective than an application every other day. So, unless you’re willing to regularly spritz down your boat with eucalyptus oil, bobcat urine is likely to prove a much better bet.


Myth: Any boat cover is better than no boat cover. For instance, those cheap blue tarps, which might not last more than a couple of seasons, will protect your boat just as well as a canvas cover or shrink-wrap since they keep the sun, rain and snow off your pride and joy.

Fact: Cheap tarps often do more harm than good. The checkerboard pattern of filaments on them is slightly abrasive, and if the cover shifts or flaps back and forth in the wind, it can cause wear on paint, gel coat and other finishes. The problem is made worse if dust or debris gets trapped between the tarp and the boat’s surfaces.

Cheap tarps also tend to rip and tear if they’re subjected to the weight of snow or pooled rainwater. While it might seem like a handy economical option, in the long run, depending on a tarp is a poor decision. If you’re forced to use one in an emergency, be sure to protect outboard cowls, teak and finished surfaces with old sheets or blankets secured in place under the tarp.


Myth: If storing a boat in the water over the winter, leave a lightbulb turned on and hanging in the bilge and/or head compartment when temperatures threaten to drop below 32 degrees. The heat created by the lightbulb can prevent freeze damage.

Fact: Yes, an illuminated lightbulb can help warm a bilge, but it’s also a serious fire hazard. In fact, many insurance policies explicitly prohibit this practice.

The only proper way to heat any compartment in a boat left in the water during winter is with a dedicated marine heater that meets or exceeds American Boat & Yacht Council® (ABYC) standards. That means it’s ignition- and spark-protected, moisture resistant, and will shut down automatically in case of failure.

Store it Right

Sure, it’s difficult to pack the boat away for the winter, and all boaters are right there with you in pining for the day when they can pull that cover off the boat, fire up the engine and once again feel a waterborne breeze blowing across their faces. But never fear. Spring commissioning will be here before you know it, and there’s no doubt all boaters will be more than ready for it. Plus, now that you know the truth behind those winter storage myths, your boat will be ready for it, too


THE SCRIPPS RESEARCH INSTITUTE is a registered service mark of Scripps Research Institute, the Not-For-Profit Corporation. AMERICAN BOAT & YACHT COUNCIL is a registered service mark of American Boat & Yacht Council, Inc. All other trademarks belong to Brunswick Corporation.
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