BRRR….Winter has arrived in the Pacific Northwest, and most of us are not using our boats as much. Now is the time to do a little winter boat maintenance to help protect and preserve your boat for the winter while you’re skiing or hiding out in warmer climates. Here’s a quick list of tasks, most of which are easily accomplished:

• Oil: Change or have your engine oil and filters changed, but first, draw oil samples and send them into the lab for analysis. Oil samples can give you an early warning of problems brewing in your engine. If it’s time to change the transmission oil (usually every 250 hours) do this as well.
• Coolant: Check to make sure you have enough coolant and that it has enough antifreeze in it. Before you top it up, be sure that you know what kind of coolant it is—don’t assume that just because it’s the same color it’s the same type—color doesn’t mean much anymore. Check the engine manual or your last service receipt to see what’s recommended or what was used last time. You definitely don’t want to mix ethylene glycol (old stuff) and propylene glycol (new stuff)—the result is a thick goo that will shut you down and is very difficult to get out of your engine.
• Fuel: Fill your diesel tanks to reduce the amount of exposed tank wall as this is where condensation can form. Add fuel additive with a biocide to prevent growth in diesel tanks. For gas engines, consider draining portable tanks (running out the fuel or properly disposing of used fuel.) For whatever is left in the tank, add a fuel stabilizer to prevent fuel distillation into varnish. This might also be a good time to change the fuel filters and clean/drain the fuel separator.
• Batteries: If you have conventional lead-acid batteries, top up the electrolyte with distilled water. Check and clean the contacts on your batteries to ensure good connections. Check your shore power battery charger (or inverter) to make sure it’s working, and set for the correct charging profile for the type of batteries you have. Check the battery switches to make sure all banks are being charged. Turn off any systems that don’t need to be on.
• Through-hulls/seacocks: Go through the boat and close any seacocks that don’t need to be open (scuppers and deck drains should be open). As you do this, open and close each valve multiple times to help lubricate them. If they are stiff, consider closing it and removing the hose, then adding some waterproof lubricant, such as Lancote. If you close through hulls that must be opened before you start the engine, then add a tag to the key or tape over the start button to remind you to open the seacocks (don’t forget the generator!). If you are on the hard, leave all the seacocks open.
• Hatches and windows: Take a close look at your hatches, portholes, and windows—gaskets dry out over the summer, and often leak when the rains come. Tighten the hatches and portholes just enough for the gasket to make contact—if you need to torque them your gasket is probably shot.
• Ventilation and heat: The most common reason fires start on boats is heaters left on unattended boats. The key to preventing mold and mildew on boats is ventilation more than heat. Make sure that there’s some way for air to move in and out of your boat, whether dorades, or mushroom vents, rain protected portholes, or even opening hatches to the engine room (which is ventilated.) Low wattage heaters such as “pancake” type are good, or thermostatic forced air. Make sure any heater has tip-over protection (boats rock!), over-current protection, and place them on hard surface (not carpet!) Open as many of your cabin and cabinet doors, drawers, and storage hatches as possible to encourage airflow. Consider using chemical dehumidifiers, such as Damp-Rid, No Damp, or similar, but be sure to place them where they can’t tip over, and you’ll need to check/drain them often.

A note on electric dehumidifiers: An electric dehumidifier does a great job but there are two key considerations: First, you’ll have to route a drain for the condensate or check and drain it often. Second, home appliances like these with three-prong plugs likely have their neutral wire connected to ground which is not appropriate for a boat. If you have a galvanic isolator or isolation transformer on board, you’ll be ok, but if not, you may find the breaker on the dock turns off when the dehumidifier is plugged in, and you could be promoting stray current corrosion for you and your neighboring boats.

• Mooring lines: If you are on Lake Washington or the Ship Canal, you already know that you’ll need to adjust your lines for the changing lake level. Wherever you are, add additional lines for our winter Southerlies, and the occasional blast from the North. Secure your mooring lines at both ends, don’t loop around the cleat, and come back to the boat as this promotes chafing and is still only one line. Add chafe protection to your lines where they rub against anything. Make sure you have enough fenders, and that they are securely tied, inflated, and properly positioned for the winter winds.
• Water systems: If your boat is moored in the water in the Pacific Northwest, it is rarely necessary to drain the freshwater system, but if you are on the hard, then definitely drain the freshwater and hot water tank, engine raw water, and AC systems. This might be a great time for a treatment with a little Barnacle Buster or similar product in the engine and AC raw water lines to break down any hard growth. This is also the time to replace the raw water impeller. Make sure you put it in with a little dishwashing soap (to act as a lubricant until the water starts flowing again) and be sure all of the tines are bent in the right direction.
• Holding tank: Don’t leave “stuff” in the holding tank over the winter—you won’t like the result. Pump it out, rinsing with five gallons of fresh water and pump again, and then repeat. Add your preferred holding tank treatment (we prefer No-Flex) to the toilet and flush it through with at least a few gallons of freshwater and food-grade antifreeze. Run at least a gallon of the same mix through each additional head to clean the lines.
• Bilge pumps: Check to make sure your bilge pump runs on automatic by lifting the float switch if you have one or use a damp sponge or paper towel across the contacts on non-float switch actuators. Put water in the bilge and make sure the pump actually drains it, not that it just turns on. If you can dismount the pump from its base, do so and clean the impeller and screen. Clean any debris from the bilge that might plug the pump. Make sure the bilge pumps are set for “AUTO” and that the breaker, if any, is on. Lastly, make sure your high-water alarm is working and loud (you do have one, right?) Many dock security personnel and liveaboard neighbors have saved boats from sinking because they heard a high-water alarm.
• Shaft seals: Check your prop shaft and rudder post seals to make sure they’re not leaking. A convention prop shaft “stuffing box” type seal may drip once a minute when not under way, but no more. Rudder shaft seals and dripless seals should be dry and clean. If you have a dripless shaft seal, such as a PSS or Tides Marine, after you inspect it, pour some fresh water over it to wash the accumulated mineral deposits off to reduce abrasion and corrosion.
• Electronics and electrical: If you have exterior electronics that can be dismounted and brought in, do so. Spray any electrical connections that are exposed to the elements (chart plotter, downrigger, tiller pilot, windlass or davit remotes, USB plugs, etc.) with a corrosion inhibitor (CorrosionX or WD-40). Consider giving all your exterior light sockets a blast as well.
• Fridges and freezers: Don’t forget to empty these and turn them off. These systems can drain batteries fast if the power goes out and you’ll want that power for your bilge pumps. Prop the doors open after you empty them, or you will have a nasty science experiment in the spring if you don’t.
• Sails: If you are leaving sails on for the winter (we don’t recommend it) make sure the headsail is evenly and tightly furled with at least three wraps of sheets around the sail. Be sure the boom cover is well secured. Secure your halyards so that they don’t chafe or slap in the wind (leaving your halyards to slap is, or should be, a criminal offense.)
• Upholstery: Bring as much of your exterior cushions, canvas, and covers inside as possible. Better yet, take them home if you can. Inside the boat, prop up all the cushions to promote airflow, pulling them away from exterior hull sides where possible. Place an underlayment, such as Dri-Dek, Hypervent, or AirGuard, under your mattresses to promote air circulation. Pull back the sheets and bedspread so they don’t block the air flow.

Lastly, make sure your name and phone number are posted in the window of you boat where it can be seen from the dock. A dock neighbor may see something that can save your boat or your wallet, but only if they know who to call.

This is by no means a comprehensive list, but during our surveys we constantly see costly damage to boats that could have been prevented with these simple steps. Take the time now—it’s far easier to take these preventive winter boat maintenance steps than to try to fix the results of not having done them.