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Winterizing Your Boat

Last weekend, I was in Chicago for a weekend of football and fun with friends and I noticed that many of the local boaters there were pulling their boats out of the water for the season.  Watching the boaters there going through their annual ritual of saying goodbye to one of their favorite past times made me glad that I do not live up north.  It did, however, bring to mind that I needed to write an article about winterizing your boat.  The types of engines and other systems on boats varies widely so make sure you are familiar with your boats systems before you attempt to winterize it or have a professional do it.  This article is meant to provide a basic understanding of the process.

Why Do We Winterize

Depending on what type of boat that you have and how it is configured, water may reside in the cooling cavities of the engine, transmission, and air conditioning/heating systems.  If your boat has fresh running water and/or a head, there is also water in the piping and holding tanks as well. 

If you are an avid boater, you know that water can be powerful.  Ice can be even more powerful.  When water freezes, it expands.  If one of these previously mentioned areas contains water and that water freezes, the expansion can be enough to cause damage.  Yes, the simple process of water turning to ice can even crack an engine block.  Winterization hopefully allows us to avoid this situation.
Failure to winterize can result in damage to your engine such at this cracked block.

How do I Winterize?

Every boat and its systems differ but here are some of the basics:

Engine – One way to winterize an engine is to remove all water from the inside.  This is usually done by disconnecting cooling system hoses or draining the water out using valves that have been installed into the block for this purpose.  If there is no water to freeze, damage does not occur.  One of the downsides of this method is that it is often difficult to ensure that you have removed absolutely all of the water. 

Another way is to replace the water with antifreeze.  Depending on your engine type, this can be done via connectors built into the engine for this purpose or by pumping antifreeze in via the fresh water intake.  I personally like this method better as you do not have to worry about whether there is still water in some of the passages.  Some engines are not raw water cooled.  In other words, they already use antifreeze in the engine and there is a heat exchanger that exchanges the heat between the antifreeze and the external body of water.  If your boat is set up this way, winterization is still necessary as failure to do so could result in damage to the heat exchanger or hoses. 

Water Systems – Some boats have running water systems which can include anything from holding tanks, heads, hot water heaters, faucets and pipes (usually plastic hose).  Again, if these are not winterized the expansion that occurs when water freezes can cause damage. 

As mentioned previously, one way to prevent this is to empty all of the water but you still have the same concerns as with your engine, getting all of the water out.  A preferred method (in my opinion) is to use antifreeze designed for marine and RV water systems.  It is important to not use antifreeze designed for engines.  This type of antifreeze may include Ethylene Glycol which is extremely poisonous.  You do not want to introduce this type of antifreeze into your boat’s fresh water system.  Marine and RV antifreeze  is ethanol based and designed specifically for fresh water systems on boats and RV’s.  
Marine/RV antifreeze is non-toxic and used to winterize your boat's fresh water system.

Winterizing your fresh water system is easy:

1.       Make sure your hot water heater is off (if your boat has one).

2.       Empty all existing water from your fresh water holding tank by turning on the faucets until they run dry. 

3.       Go to a pump out station and empty your waste water holding tank.

4.       Put in several gallons of marine/RV antifreeze (the pink stuff).  How much you need depends on the size of your boat’s system. 

5.       Turn all faucets on until they run pink (hot and cold sides).  If your head pulls water from your fresh water tank, don’t forget to flush it until the water in the bowl is pink.

Air Conditioning System – Your air conditioning system also has water in it.  To winterize it, take the following steps:

1.        Find out where the seacock is for the water intake for the system and close it. 

2.       Look for the canister in the water line to the A/C unit and open the top.  This is also a good time to check the screen and clean it. 

3.       Turn on the A/C unit to its coldest setting and pour marine/RV antifreeze into the canister as the unit drains it.  Keep pouring antifreeze in until the discharge water is pink.

4.       Replace the filter and close the canister.

5.       Leave the seacock closed until it is time to de-winterize.  
Your boat's air conditioning will have a strainer cannister that you can access for winterization.

Other Tips for Cold Weather

1.        In some climates, even though it may get cold in winter, lakes and rivers do not freeze and you can leave your boat in year round.  If you have shore power, a bilge heater is a good idea.  It will keep the engine compartment warm enough to keep your boats systems from freezing.  Of course, an ice storm that knocks out the power will render your bilge heater useless so you do need a plan B just in case. 

2.       If you plan to go more than a couple of weeks without using your boat (as many people do in the winter months) don’t forget fuel treatment.  For just a few bucks, it can save you some headaches come springtime.  

Don't forget fuel stabilizer if you are not using your boat for a long time.

3.       Cover your boats bilge vents in cold weather, this makes it harder for cold air to get in.  Just don’t forget to uncover them when it’s time to use your boat. 

4.       In the water is better than out of the water when the temperature falls.  If cold weather moves in, your boat is better off in the water.  This is, of course, assuming that the body of water that your boat is sitting in does not freeze.  The air temperature may be 20 degrees but if the water is 42 degrees, it can serve as a heat sink to keep your boats systems from freezing at least for a while.  Regardless of the temperature of the water, prolonged air temperatures below freezing can still cause problems if you do not winterize or have some way to keep things warm. 

5.       If you are storing your boat for a long period of time, you may also choose to use fogging oil to properly protect the internal systems from corrosion when not being used.

6.       Consider changing your oil and other lubricants BEFORE winter layup and not in the spring.  With use oil can break down and develop a buildup of acids that can adversely affect the internal engine parts when sitting for long periods.  Changing the oil before storing can provide just a little bit of extra protection.

Got any other tips for winterizing?  Let’s hear them below.

Happy Boating

Captain Frank
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