The best way to learn about the process of winterizing a vessel is to learn on the job. Boats of all sizes have similar winterizing tasks so this guide will cover most items that need to be on the checklist to prevent damage or loss of the vessel. Unless you are in the Arctic.
Ships and smaller craft have many of the same fixtures they just vary in size considerably. Some of these things are done by outside contractors in cases where special equipment is needed. Another case is where there may be an environmental hazard. This is the problem with marine antifreeze which can no longer be disposed of by in water flushing or dumping into a sewer.
These many gallons, and sometimes drums, of liquid need to be recycled or treated a hazardous waste.
The time to decide on your course of winterizing is well before the snow falls. It will depend on your climate and the salinity of your water.
In freshwater environments open circuit cooling of engines and other equipment is still very common. These vessels may sustain major engine and seacock damage if water is not fully drained from the system in boats which are dry docked through the winter. The pressure of ice is so great that it will burst heavy iron castings that contain cooling passages. Engine block eaters alone are used in vessels with minimal freezing chance or are used as a backup system to draining or antifreeze.
If you are unlucky enough to lose power in a freezing environment that is also fresh water the possibility of seacock failure is high due to expanding ice. Many vessels have been lost to seacocks blown out from ice pressure.
Crushing of the hull must be considered as a real danger. Failure of circulators made up of subsurface electric motors and propellers or bubble systems will lead to quickly encroaching ice and shifting of the ice may puncture the hull. For those in river environments, the spring thaw is very dangerous since a torrent of ice is common in some places.
Once the engine and hull are taken care of then it’s on to the strainers. They should be cleaned and the impeller removed to avoid cracking.
Batteries are next on the list. They should either be trickle charged through the off season or removed and stored in a ventilated place above freezing. Solar chargers are available inexpensively for this task and are a good choice if your dry dock does not offer power in the winter.
Don’t forget batteries for portable electronics. Most lithium and NiMh batteries are not hurt by the cold, but bring and lead acid batteries inside until spring.
In fiberglass areas where moisture might accumulate it’s wise to apply a good coat of wax in autumn to keep fiber from being lifted from hairline cracks.
One of the biggest controversies faced when winterizing is to cover or not to cover.
Covering portions of a vessel with tarps is an age old practice. The benefits are a lack of melt water in the bilge in spring. Some water will always find its way in but the tarp deals with problem areas that don’t seal well.
Since many dry docks and winter quarters are located adjacent to shoreline, winds are often strong and quickly destroy even the heaviest and tightest tarps.
After much debate it seems like more damage is done to fixtures like mounts and rails than is prevented by the tarp. In short; it gets windy, the tarp shifts or tears, and the remnants catch on antennas, sensor, mounts and any little thing that sticks up.
Finally, make sure you check the galley, pantry, and other place food might be kept for things that can freeze and burst. A few forgotten sodas that burst and leak when they thaw will add many hours to your spring clean-up.