Thursday, September 25

Winterizing, Part Deux

By Andrew Spaulding

Michael wrote a comparatively comprehensive article last week on winterizing tips, suggestions, and best practices. In covering sailboats he wrote about items that also apply to powerboats such as batteries, seacocks, and fuel treatments. I’m going to cover additional items and add notes to last week’s list. Please let me know if you have any questions. My email is

Stern(out)drives – Stern drives work great until they don’t. Most people forget all about their sterndrives until something goes wrong, usually involving a lost weekend or two in the summer. The first thing to do is visually inspect the drive soon after it comes out of the water. You want to look for signs of corrosion, damaged wires and hoses, propeller dings, and any scrapes on the drive. When you change the oil, inspect the initial oil level and check the oil for signs of water. Inspect the drive and shift bellows for cracking or dry rot.

Stuffing box – On the way to the boat yard inspect the stuffing boxes for excessive leaking. If there isn’t any more adjustment, it is time for a re-pack. Underway a drip every 10-15 (ish) seconds is ok. Without the engine running, there should be a drip every 30-60 seconds. The trick is that you want to make sure that the packing gland stays cool to the touch. If it gets hot there isn’t enough water flow. Warm is ok, but not hot.

Engine belts and hoses –While you are pumping the engine full of winterizing fluid, take the time to inspect your engine belts for glazing or cracking. Also, check the belt tension and the pulley alignment. Excessive belt dust on the engine is a great indicator of a problem. At the same time, check your hoses and hose clamps. Purchase the correct size nut driver (looks like a screwdriver but with an end for tightening nuts) for your hose clamps and give each one a quick twist.

Windshield wiper fluid – Don’t forget this one! I’ve seen 10 year marine industry veterans forget to winterize the windshield washer fluid. The blue stuff you purchase at the convenience store mid-summer might not have freeze protection.

Engine panel instruments – The winter is a great time to send out individual gauges for repair. We “have a guy” that fixes all sorts of gauges, so if yours aren’t working take them out and have the store send them for repair.

Propellers – Fuel isn’t getting any cheaper and having your propellers tuned is a great way to maximize your fuel savings. The prop shop hates to get propellers in March. They’d much rather have work to do in December.

Batteries – Make sure they are fully charged, then disconnect the battery cables, and then clean the battery terminals and battery cable terminals. Most boats have a current draw from something all the time. For example, if you have a CO monitor, it is likely wired direct to the batteries and uses current to test the air.

Bilge blower system – Non-working bilge blowers leave the boat in a dangerous condition. When spring rolls around and you want to jet to the harbor, their repair is often deferred. If you have blower screens and/or filters now is the time to clean them up.

Hull plugs - Make sure hull plugs are removed; feel free to remove transducers, or drill a hole in the bottom/transom to stop water from collecting in the boat. Don’t kid yourself, water gets into every boat that is stored outdoors. If you’re not sure about drilling a hole in the boat, I’ll walk you through it. We make it a habit to pull out the hull plugs when we haul boats.

Safety gear - Check fire boys, fire extinguishers for service dates, and send out for re-certification over the winter. Check the service date on your flares and your EPRIB batteries too.

Tools - Oil your onboard tools to keep them from rusting over the winter. There is nothing worse than finally deciding to get off the couch to do some boat work to find your tools rusted in a lump. Use my favorite corrosion inhibitor CorrosionX for this task.

Seacocks - A few more words about seacock winterizing: you must operate the sea cock after the boat is out of the water to let trapped water drain out. Water gets trapped between the “ball” and the housing. It will drain out at about halfway open/closed. Certain types of seacocks and older worn seacocks are worse than others, but there isn’t any reason not to exercise all of your seacocks any way. Take this opportunity to lubricate them with lithium grease!

Air conditioning and refrigeration – Likely your A/C is water cooled, but your refrigerator may be air cooled (like at home). There isn’t any winterizing to do if your system is air cooled, but if A/C or refrigeration is water cooled it is essential that it gets winterized. The process is very similar to winterizing the potable water system. Pull the hose off the intake seacock and put it into a bottle of non-toxic antifreeze. We use the -50 non-tox that we use on the water systems. Turn on the pump until the non-tox comes out of the overboard discharge. Take note; if you have more than one A/C unit you’ll need to do this process for each units. Many larger systems have one cooling water pump for multiple condensers with multiple discharges. Typically, the discharge will be near the condenser; therefore, the overboard discharge thru-hull fittings are spread around the boat. Make sure the non-tox flows out of all of the cooling water discharges before turning the pump off.

Coolant test – We test the internal engine coolant’s freeze protection on every boat we winterize. You’d be surprised how many don’t have the proper freeze protection. The coolant can get watered down over time though top-offs with water, age, or accumulated condensation. Also, if your boat was down south long enough to have maintenance done on the engine cooling system, make sure to get your engine antifreeze tested for freeze protection. Many boats down south, particularly those with large diesels, run an internal coolant fluid that doesn’t have any freeze protection.

In closing, your fall goal is to do anything and everything you can possibly think of doing in the fall so that your already long work list in the spring doesn’t get any longer. Again, if you have any questions on winterizing please contact me at or Michael at

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