Winterizing Your Boat...What are you Missing?
It’s that time again…
For those of us not living in an ‘endless summer’ - it’s that time of year where we stow away the gear and get our vessels ready for winter. Anyone who’s gone through this change of seasons at least once has their own list, with many familiar items which include:
Treating your fuel system with a stabilizer additive (if not completely drained!)
Clear out your bilge of any standing water & clean well
Drain water from any storage systems / heads and purge their respective lines
Send your vessel off to storage at your local yard or property, sealed up and ready for the off season
Many of the above are habit we follow season in and season out. One question I’ve heard raised often is ‘what am I missing?’. Are there items not on the regular list I should keep an out for so I’m not caught off guard in the spring?
Winterization Misses
The following are a list of items sometimes overlooked in winterization you may want to review prior to putting your boat up for the off season:
Batteries
This falls into two camps: your primary engine battery as well as any other batteries found aboard. For your engine battery, take stock of its condition prior to sealing up for the season. Many types of batteries (particularly deep cycle marine batteries) generally do well if not used for some time. That assumes however your battery is in good shape and prepared to go the distance. If your battery is already on the way out, the long time between use mixed with potentially freezing temperatures can knock your battery out come spring time. If you’re not sure of your batteries condition consider removing it for warmer storage - say in a garage or basement - and consider a trickle charger if needed. This can save time and headache when you get ready for next season. Similarly look for any batteries left aboard as auxiliary or primary power sources for devices (fish finders, radios, EPIRBS, etc.). Like we do with seasonal decorations, think about removing those batteries altogether to save them from going bad or worse corroding out pricey electronics mid-winter.
Fresh Water System Winterization
Properly winterizing your boat's fresh water system is crucial to prevent costly freeze damage to pumps, pipes, and fixtures. Start by draining all water from the fresh water tank, then run the system until pumps run dry to clear water from the lines. Next, disconnect the intake line from the fresh water tank and place it in a container of non-toxic marine antifreeze (propylene glycol-based, never automotive antifreeze). Depending on your area you may need different temperate rated antifreeze (e.g. -50F or -100F degree). Turn on each faucet, shower, and fixture one at a time until you see the pink antifreeze flowing out, ensuring all water has been displaced from the lines. Don't forget often-overlooked components like the water heater (which should be bypassed or drained separately), ice makers, washdown pumps, and any deck or cockpit spigots. For water heaters, either drain completely using the drain plug and relief valve, or install a bypass kit to route antifreeze around the tank. Finally, pour a small amount of antifreeze down each drain to protect the drain lines and prevent any residual water from freezing. This thorough approach protects your entire fresh water system from freeze damage and ensures everything will be ready to flush and refill come spring.
Fuel System Winterization
Your fuel system deserves special attention during winterization, as poor preparation can lead to gummed carburetors, clogged injectors, and costly spring repairs. Start by adding a high-quality marine fuel stabilizer to your tank—never use automotive versions—then fill the tank completely to minimize condensation and water contamination. Run the engine for at least 15 minutes to circulate the stabilized fuel throughout the entire system, including carburetors and fuel lines. For carbureted engines, consider running until the carburetor bowl is empty or using the fuel shut-off valve if equipped. Don't overlook fuel filters, which should be replaced now rather than in spring, and drain any accumulated water from fuel-water separators. Inspect all visible fuel lines and connections for cracks or leaks, and remember to treat portable fuel tanks for outboards with the same care as your main system. Modern gasoline begins degrading within 30 days, and ethanol-blended fuels are particularly problematic, making proper stabilization your best insurance against fuel-related headaches when you're ready to get back on the water.
Cushions
I’m sure all of you have a cleaning ritual for your seat cushions and covers - and that’s a great start! Beyond just cleaning prior to storage consider how you store your cushions. Rather than keeping them in place, consider tilting them to the side or removing them from their usual spot to allow air flow in and around the areas they cover. If there are storage areas or other comportments underneath seats, the trapped air could lead to moisture buildup and mold over a long winter. Even better, if space permits consider taking removable seat cushions back to your home or basement for long term storage. If needed this could also be a prime opportunity to repair or resurface cushions you would not otherwise have time for on the on season.
Food & Personal Care Items
It may seem like a no-brainer, but oftentimes leftover food, suntan lotion, and other items can left in compartments lost for the winter. Liquid items can be prone to freezing, cracking, and leaving a mess in their wake to be found during opening. Furthermore, any leftover food can attract pests who may be searching for a mid-winter snack. Take extra care to shake out all lockers, compartments, and the spaces in between where items can be lost during regular cruising.
Lines & Sheets
While generally kept onboard during the offseason, it’s a good habit to inspect any lines and sheets for signs for wear. Items that need replacement should be identified and lined up during the long winter months to ensure all gear is seaworthy at the start of the year.
Drain Plug
Another ‘it seems obvious’ item - but this should be looked at on two fronts. The first is to remove the drain plug if you feel there could be water accumulation you don’t want sitting in your bilge and potentially freezing. This is dependent on how and where you plan to store your vessel during the off season. The second is to take the time while your boat is out of the water to inspect it and ensure you won’t have any issues rethreading or holding a seal when the time comes to use it again. When in doubt, use the time to address while you’re not waiting to get back on the water.
Moisture Absorbers
Even the best job at cleaning up moisture will inevitably leave some behind. This coupled with a tight shrink wrap and the ‘greenhouse’ effect during winter will lead to moisture getting into the air inside your vessel. Consider using some moisture absorbing containers to draw in any excess water and holding it until you can open up in the spring. If you have access to power a dehumidifer is a great choice - just don’t forget to have a drain or routinely empty the bucket.
Many of the above items are generally done throughout the year, but often overlooked or not reviewed in depth during the winterization process. Take advantage of the extra time at season’s end to ensure a solid start to the next one.