Winterizing Your Boat: Choosing The Right Antifreeze

Winterizing your boat is essential to protect it from freezing temperatures, which can cause water to freeze and expand, damaging your engine. To winterize a boat, you need to drain the water from the engine and replace it with antifreeze. The type of antifreeze you use is crucial, as the wrong choice can be ineffective or even cause damage. Marine antifreeze is specifically designed for boats and is non-toxic, while automotive antifreeze contains harsh chemicals that can harm boat engines and the environment. The antifreeze you choose should be non-toxic, odourless, and offer adequate temperature protection for the climate you're in. It should also contain propylene glycol, which is safer and more effective than ethylene glycol.

The difference between antifreeze and engine coolant

To winterize a boat, you can either drain the system and leave it dry or fill it with antifreeze. Antifreeze is a crucial component of winterizing a boat as it prevents water from freezing and expanding, which can cause damage to the engine.

Now, here is the difference between antifreeze and engine coolant:

Although antifreeze and engine coolant are often used interchangeably, they are not the same thing. Antifreeze is made of ethylene glycol or propylene glycol and is the basic ingredient in coolant. However, to create coolant, antifreeze must be mixed with water in a 50-50 ratio. This mixture is then used in the cooling systems of "water-cooled" vehicles.

Coolant is necessary as water alone does not have the cooling ability or protection against freezing that engines require. Water boils at 212°F and freezes at 32°F, which can cause issues in an engine. A 50-50 mix of antifreeze and water lowers the freezing point to -35°F and raises the boiling point to 223°F or higher.

Antifreeze, on the other hand, has a freezing point of 0°F on its own. It also contains corrosion inhibitors to prevent rust that can damage the radiator, water pump, and other cooling system parts. When winterizing a boat, it is crucial to use non-toxic antifreeze, as most of it will be ejected into the water when the engine is first started after winter. Engine coolant, on the other hand, is toxic and should never be used for boat winterization. It should only be used in the self-contained freshwater side of the engine cooling system.

In summary, while related, antifreeze and engine coolant serve different purposes. Antifreeze is a key ingredient in coolant, but it must be mixed with water to create the final product used in engine cooling systems. When winterizing a boat, it is important to use non-toxic antifreeze to protect both the boat's engine and the surrounding water environment.

Why you shouldn't use RV antifreeze for your bilge pump

When winterizing your boat, you might be tempted to cut costs by using RV antifreeze instead of marine antifreeze. While the two products are chemically the same, there are some important reasons why you shouldn't use RV antifreeze for your bilge pump.

Firstly, RV antifreeze is typically rated to -50°F (-45°C), which may not provide sufficient protection for your bilge pump. This is because propylene glycol, the primary ingredient in RV and marine antifreeze, will start to form a slush at temperatures close to its freezing point. This slush can be harder to pump, and if your bilge pump is triggered during a deep freeze, it could get damaged. A higher-rated antifreeze, such as a -100°F (-73°C) product, will have a much lower freeze point and is much less likely to form slush inside your pump.

Secondly, RV antifreeze is often pink, which generally indicates the lowest level of protection. Darker colours like blue, purple or green indicate more protection. Therefore, if you use pink RV antifreeze in your bilge pump, you may not be providing enough freeze protection for that critical system.

Finally, while RV antifreeze can be more affordable, it is important to consider the potential costs of repairs if your bilge pump is damaged due to insufficient freeze protection. It is always better to invest in the proper antifreeze to ensure your boat's systems are adequately protected during the winter.

In conclusion, while RV antifreeze may be tempting due to its lower cost, it is not suitable for all systems on your boat, including the bilge pump. To properly winterize your boat and protect your investment, it is important to use the appropriate type and rating of antifreeze for each system.

Why propylene glycol is a safer choice than ethylene glycol

When preparing your boat for winter, it's important to use the right type of antifreeze to prevent engine damage. While both propylene glycol and ethylene glycol are effective as antifreeze, propylene glycol is a safer and more environmentally friendly option. Here's why:

Environmental Impact

Propylene glycol is biodegradable and less harmful to the environment. It takes ethylene glycol around 10 to 30 days to biodegrade, while propylene glycol can take 20 to 30 days or more. Additionally, ethylene glycol is toxic to humans and aquatic life, with even small doses being lethal to mammals. In contrast, propylene glycol is considered relatively safe for humans and is commonly used in food, pharmaceuticals, and beauty products.

Impact on Boat Components

Propylene glycol is the preferred choice for winterizing boats because it won't damage the engine or plumbing components. Ethylene glycol, on the other hand, can cause strainer bowls to craze or crack, especially those made of nylon. It can also distort neoprene, a material commonly used in valves, seals, and impellers, potentially leading to leaks. Propylene glycol is also recommended by major marine engine manufacturers, such as Mercury Marine, for winterizing engines due to its corrosion-inhibiting properties.

Ease of Use and Disposal

Propylene glycol is a more user-friendly option for winterizing boats. It is non-toxic, so there are no special disposal procedures when draining the cooling system in the spring. On the other hand, ethylene glycol is highly toxic and must be handled and disposed of with extreme care. Propylene glycol is also available as a ready-to-use solution, whereas ethylene glycol often requires mixing, and its concentration must be monitored with a refractometer.

In summary, while both propylene glycol and ethylene glycol can effectively protect boat engines from freezing during winter, propylene glycol is the safer and more environmentally friendly choice. It is less toxic, biodegradable, and less likely to damage engine components. Additionally, its ready-to-use convenience and easy disposal make it a more practical option for boat owners.

How to drain water from your boat engine

Draining water from your boat engine is a crucial step in winterizing your boat to prevent water from freezing and expanding, which can damage engine parts. Here is a step-by-step guide on how to properly drain water from your boat engine:

• Consult your Boat's Manual: Before beginning the draining process, it's important to refer to your boat's engine manual. Different engines may have specific instructions or variations in the process, so consulting the manual will ensure you're following the correct procedure for your particular engine.
• Locate the Petcocks: Petcocks are valves that allow you to drain the water from the engine. Check your engine manual to identify the location of all petcocks.
• Open the Petcocks: Once you have located all the petcocks, open them to start draining the water. If water fails to drain freely from a petcock, it may be clogged. In such cases, remove the petcock and use a tool or coat hanger to clear any rust or debris blocking the opening.
• Drain the Sea Strainer, Seacock Body, and Water Lift Muffler: In addition to draining water from the engine, don't forget to drain other components such as the sea strainer, seacock body, and water lift muffler if your boat is equipped with these.
• Reach Operating Temperature (for Raw-Water-Cooled Engines): If your boat has a raw-water-cooled engine, it's important to ensure the engine reaches operating temperature before adding antifreeze. This is because a thermostat blocks water flow in some cooling passages until the engine heats up. Running the engine until it reaches operating temperature ensures the thermostat is open, allowing the antifreeze to circulate properly.
• Use Antifreeze: After draining as much water as possible, you'll need to fill the engine and related plumbing with antifreeze. Choose a non-toxic, propylene glycol-based antifreeze that is specifically designed for marine use. Follow the manufacturer's instructions for diluting the antifreeze to the appropriate ratio.
• Circulate Antifreeze Through the Engine: With the boat in the water, close the intake seacock. Fill a bucket with undiluted non-toxic antifreeze. Remove the raw water intake hose from the seacock and place it in the bucket. Start the engine and run it at idle until antifreeze discharges from the exhaust outlet for at least 30 seconds.
• Secure the Intake Hose: Once antifreeze is circulating and discharging from the exhaust, secure the intake hose back onto the seacock.
• Fog the Cylinders (for Gasoline Engines): If your boat has a gasoline engine, fog the cylinders by spraying fogging fluid or light motor oil into the flame arrester on the carburetor while the engine is running. This will help protect the internal engine parts from corrosion during storage.
• Wrap and Cover the Engine: After fogging the cylinders, turn off the fuel valve and run the carburetor dry. Wrap duct tape around the flame arrester and cover the top of the engine with plastic after it has cooled down. This provides additional protection against corrosion.
• Store Outdrives and Outboards in the Down Position: To prevent water from entering and freezing, store outdrives and outboards in the down position. This will allow any remaining water to drain and reduce the risk of ice cracking the housing.

By following these steps, you can effectively drain water from your boat engine and winterize your boat, protecting it from potential freeze damage during the cold months.

Why you shouldn't use auto antifreeze for your boat

When preparing your boat for winter, it is important to invest in the right antifreeze. While auto antifreeze may be tempting, it is not suitable for boats and can cause extensive damage. Here are several reasons why you should avoid using auto antifreeze for your boat:

Toxicity

The key difference between auto antifreeze and marine antifreeze is toxicity. Auto antifreeze is designed for use in car engines and typically contains ethylene glycol, a highly toxic substance that can cause serious harm to humans, animals, and the environment. On the other hand, marine antifreeze is non-toxic and often contains propylene glycol, which is much safer for the environment and marine life.

Corrosion and Engine Damage

Marine antifreeze is formulated with rust and corrosion inhibitors to protect your boat engine during winter storage. In contrast, auto antifreeze does not offer the same level of protection against corrosion. Additionally, auto antifreeze can damage components of your boat engine and cooling system, leading to costly repairs.

Environmental Impact

If auto antifreeze leaks into the water, it can have devastating effects on aquatic life. The chemicals in auto antifreeze can kill fish and other marine organisms, cause malformations, and critically damage the local habitat. Even if you properly dispose of auto antifreeze, it can still leach into the surrounding environment and cause harm.

Safety

The sweet taste of auto antifreeze can attract animals and young children, posing a serious health risk. Ingestion of auto antifreeze can cause damage to the central nervous system and can be fatal if left untreated. Marine antifreeze, on the other hand, has no taste, making it less appealing to animals and safer for use around children.

Alternative Options

While marine antifreeze is specifically designed for boats, there are alternative options that can be used instead. RV antifreeze, for example, is chemically the same as marine antifreeze and can be used for most parts of the winterizing process. It is typically less expensive and readily available. However, it may not be suitable for all systems, such as the bilge pump, where a higher level of protection is required.

Frequently asked questions