Cold-Weather Boating: Cold Water Safety, Gear and Engine Care in Late Fall and Winter

Look up water temperature (NOAA buoys and local reports) as well as air temperature, wind and waves. BoatUS points out that fall and winter winds and cooling water can build stronger waves and currents, and fog is more common. If the numbers say "cold," plan a shorter trip close to shore, with company.

BoatUS says a float plan, or at least telling a trusted person where you're going and when you'll be back, matters even more when it's cold and dark early. Tell them when you're back, too. Check that fuel, pump-out and launch services you'll need are open.

The NWS says a life jacket greatly improves survival: it keeps your head up through the gasping phase and buys time once your muscles stop working. BoatUS adds that it's also a warm extra layer. For frequent winter boating, consider a USCG-approved float coat (a parka with foam flotation inside). The Coast Guard's advice is simple: the best life jacket is the one you'll actually wear.

BoatUS reports that most inflatable life jacket makers don't recommend them at 40°F and below, because they inflate more slowly and give less buoyancy near freezing. Read your model's label and manual. In very cold weather, a foam vest or float coat is the safer choice. See the inflatable life jacket care guide.

BoatUS's advice: synthetic or merino wool base layers (wet cotton pulls heat away), a waterproof outer layer, good waterproof gloves and insulated waterproof boots, and bright colors so you're easy to spot. For paddling or small-boat sailing, where falling in is likely, wear a wetsuit or dry suit; a Coast Guard search-and-rescue controller quoted by BoatUS recommends a dry suit once the water drops below about 60°F. For cold water, pick a life jacket with a light and, if you can, a splash guard: a cold-water physiologist in the same article warns that waves breaking over the face are a big drowning risk once you can no longer hold your head up. Pack a full change of clothes in a dry bag. Sunscreen and eye protection still matter; spray and wind add up fast.

What "dressed for the water" really means: the National Center for Cold Water Safety says most people get the strongest cold shock in water between about 50 and 60°F if they have no wetsuit or dry suit, and that the air temperature doesn't matter once you're in. Its test is practical: would what you're wearing keep you calm and able to use your hands long enough to climb back aboard, swim a short distance or wait for rescue? A wetsuit only counts if it's thick enough and fits snugly; a dry suit only works if it doesn't leak and has warm layers under it. Try your gear in the water close to shore before you rely on it.

Make sure the VHF works and, if it has DSC, that your MMSI is programmed so a distress call sends your position. BoatUS suggests a personal locator beacon for each person as backup. Cold drains batteries faster, so charge phones and handhelds fully and carry a power bank. Mylar emergency blankets are cheap and light. See the VHF and PLB guides.

With fewer boats around, going overboard alone is especially dangerous. Wear the engine cutoff lanyard or a wireless ECOS fob, as BoatUS suggests for solo boaters. Make sure there's a boarding ladder you can reach and use from the water with cold, clumsy hands. See the kill switch, wireless fob and man-overboard gear guides.

BoatUS notes that cold reduces battery capacity. Start each trip with fully charged batteries, check terminals, and don't run electronics for long with the engine off. A weak battery that started fine in summer may not crank on a cold morning. See the marine battery guide.

Let the engine idle and warm up as your owner's manual describes before putting it under load. Check the telltale or exhaust water flow right after starting; ice or slush at the water intake can block cooling. Expect lower fuel economy in rough, cold conditions and keep a good reserve. Make sure navigation lights work: BoatUS reminds boaters that daylight fades fast in fall and winter, and lights are required after dark and in reduced visibility.

Spray freezes on decks, rails and windshields, making footing slick and adding weight up high. Ramps and docks ice over, especially in the morning. Keep the deck clear, wear boots with good grip, use handholds and move carefully. Avoid skim ice: it can cut into hulls and damage props and lower units.

BoatUS's advice: expect the gasp reflex and focus on getting your breathing under control; kick off heavy boots that drag you down; if you can't get out, cross your arms over your chest and draw your knees up to hold heat (the HELP position); and stay with the boat or anything that floats, because a bigger object is easier to spot. Get out of the water as fast as you can; the NWS warns that body temperature can keep dropping after rescue, so get the person warm, dry and sheltered right away. BoatUS cautions against applying heat to the arms and legs of a hypothermic person. Call for medical help.

More from the cold-water experts BoatUS interviewed:

• In the first minute or two, protect your airway. Hold on to something, or lie back and float; don't start swimming right away. The cold-shock gasp passes in about a minute or so, and knowing that helps you stay calm.
• Then you have roughly 10 to 20 minutes of useful hand and arm strength to climb out, grab a line or get to something that floats. Use it on the things that matter most. If you must move, kick with your legs and keep your arms close to your body.
• Getting someone aboard: lift them as close to horizontal as you can, because hauling a cold person out straight up can make blood pressure crash; if their airway is at risk, get them out any way you can. Once aboard, keep them lying down, still and wrapped up, and keep encouraging them ("keep fighting") instead of telling them to relax. People can collapse just before, during or after rescue.
• The National Center for Cold Water Safety adds that it's very hard to tell "badly chilled" from true hypothermia without a core temperature, and children cool much faster than adults. Treat any cold, shivering, confused person as an emergency.

BoatUS warns that household space heaters tip over easily on a boat, open-flame heaters must never be left unattended (including while you sleep), and any fuel-burning heater can produce carbon monoxide. Use heaters made for boats, follow their instructions, and have a working CO alarm. See the cabin heater and CO detector guides.

Anything that holds water can freeze and crack between trips:

• Outboards: after use or flushing, Mercury says to tilt the motor all the way down so trapped water drains from the cooling passages. Store it down when a freeze is coming.
• Inboards and sterndrives don't drain themselves; if a hard freeze is forecast, drain the engine per your manual or winterize it.
• Livewells, baitwells, washdown pumps and raw-water strainers: drain them and leave valves open per the pump maker's instructions.
• Freshwater lines and the head: drain or protect them if the boat sits in freezing weather.
• Boats left in the water need bilge pumps powered, batteries charged and, in ice country, a de-icer or bubbler. See the in-water winter storage guide.

BoatUS notes you burn more calories staying warm and still lose fluids even when you don't feel thirsty. Bring snacks and warm or cold non-alcoholic drinks; alcohol speeds heat loss and clouds judgment.