Whether you are leaving the boat in the water or in dry dock, change the oil and filter, and run the engine to circulate the new oil; top off the fuel tanks and use the appropriate additives, and change the fuel filters; fill the batteries; and clean and dress the battery terminals. Charge the batteries fully, and then disconnect the terminals.

If you are leaving the boat in the water, test the bilge pumps to make sure they are operating; clean the engine's seawater strainer and flush the cooling system intake with fresh water. If you live in a harsh winter climate, you'll need to add antifreeze to the cooling line.

This is a job best done by two people. Close the seacock and open the strainer. Have several gallons of antifreeze open and ready. When your buddy starts the engine, you add the antifreeze to the strainer. It will be sucked up fast by the running engine. You want to pour quickly so that the engine does not starve for coolant and heat up (it helps to cut the tops off the antifreeze bottles). When you are down to your last gallon, have your friend cut the engine. Fill the rest of the strainer with antifreeze and replace the cap.

CAPT. ALAN R. HUGENOT

An alternative method is to add a hose attachment to your cooling line, run the hose to a five-gallon bucket filled with antifreeze, start the engine and shut it down when the bucket is empty. Either way, the idea is to fill the engine and the line with antifreeze, to protect it against the weather. Unless your engine has block heaters, you may also want to purchase marine-grade engine heaters such as those manufactured by Boatsafe Inc., and temporarily mount them in the engine compartment with wire ties. These are ambient heaters that trigger automatically in cold weather and give off only enough heat to keep the engine compartment temperature above freezing.

It is prudent to visit the boat weekly in winter to check for problems. At least once a month, run the engine under load until it reaches operating temperature of 1,000 degrees Fahrenheit (usually about 30 minutes), making sure to allow it to warm up and cool down properly. If you don't start the engine to circulate the oil, combustion byproducts will rust the inside of the cylinder walls. Then, when you restart the engine in the spring, the rings will scrape that rust down into the crankcase and your oil pump will spread the grit throughout your engine. That will speed up the wear on all moving parts.