Girding for the Silent Season

While some sailboat heaters use what’s called a balanced system, in which outside air is piped directly into the burning chamber, our Reflex heater burns the ambient air in the cabin. Without that proper ventilation, there’s a risk of depleting the oxygen below.

The threat of simple asphyxiation tended to, we turn our attention to that invisible, odorless, and insidious gas: carbon monoxide. While I check the flue pipe, deck fitting, and Charlie Noble on the heater for leaks or obstructions, Diana tests the carbon-monoxide detector.

Although the Reflex diesel-drip heater is efficient, I’ve placed a small fan behind the flue pipe to increase its effectiveness. This draws mere milliamps yet generates enough airflow to heat and dry the entire boat equally.

When we winter dockside, we plug in a high-quality electric space heater. I place it on a low, flat surface so that even the wildest wake can’t topple it, ensure that it’s pointed into a wide, open space, and clean the dust buildup from the rear intake regularly, as this can collect into sufficient tinder to start a fire. I set the adjustable thermostat to 45 F, which allows us to leave the boat for several days without fear of freezing the canned and bottled foods, water tanks, or interior plumbing and be able to reheat the interior to a comfortable temperature fairly quickly upon our return.

I keep the water tank only three-quarters full to protect it from overexpansion if the contents inadvertently freeze. Conversely, I try to keep the diesel tank as full as possible to protect it from condensation.

Naturally, through-hull fittings below the waterline deserve special attention. For our year in the high Arctic, I installed heavy-duty bronze seacocks. However, once we were in less extreme conditions, I replaced them with Marelon ball valves and have had no problems despite several severe winters. Of course, all underwater fittings and hoses require periodic inspection. I prefer T-bolt hose clamps, usually found on exhaust hoses, to the more common perforated worm-screw type. The T-bolts offer an increased area of compression spread equally over the entire circumference of a hose and can withstand more torque when tightening.

If we’ve established with certainty that we won’t need the engine, I take off the raw-water intake hose, immerse it in a bucket of non-toxic antifreeze, and run the engine long enough to fill the heat-exchange chamber, the exhaust lift box, and the side-exhaust swan neck with antifreeze. While the engine is running I inject fogging oil into the air intake. Once the engine is shut down I tape off the air intake port to minimize condensation within the engine. I then change the oil and filters to reduce the acidic wear of aged oil.

Water trapped inside the shaft’s packing gland can conceivably freeze, expand, and warp the gland or even burst the connection to the stern tube. Old-fashioned bronze glands are generally very robust and, once tightened down, require only occasional inspection. However, to prevent water ingress, modern dripless glands rely on one smooth doughnut connected to the propeller shaft and compressing against a smoothly lapped carbon or plastic surface on the stern tube. The pressure at which these surfaces meet is usually just enough to prevent water from entering but not enough to cause undo friction, heat, and ultimately wear. I loosen the grub screws on the shaft doughnut and slide it aft, thus increasing the spring tension on the stern-tube bellow. After I refasten the grub screw, I note in bold script in the logbook that I must remember to move this back to its marked original position before any motoring occurs in the spring.