Winterizing A Boat Still Parked in Water


I don’t widely publicize this, but my love for open water is second only to my love for patios. And with the coldest month quickly approaching, it’s time to explore something very important.

If you have a boat that is parked at a dock, you may be wondering whether or not it would be wise to leave your boat there for the winter. Not only is this possible, but if you follow a few key precautions, you won’t have to worry about coming back in the spring to a ruined boat.

In order to understand what you need to do to keep your boat safe over the winter, it helps to understand what your boat is doing each and every time it’s in water.

When afloat, a boat is battling against wind and weather to keep out the water that surrounds it. When ice begins to build in winter, your boat’s battle gets more intense.

Ice could potentially damage a thru-hull, snow could build up in the boat’s cockpit and submerge fittings, and other potential damage could occur.

Attention: I’m admittedly not a nautical genius. While the information below is meant to be complete, every boat is different. Leaving your boat in the water all winter long is a big decision, do so at your own risk!

When prepping your boat for winter, you’re essentially looking at all of the potential dangers that ice, cold, and snow present and fitting your boat with what it needs to avoid those dangers. For the most part, this involves protecting different fixtures and surfaces on your boat through coverings.

You’ll also need to ensure that different valves are closed, hoses are removed for drainage, and that your water system is properly equipped with antifreeze. And it gets even more intensive than that. But don’t worry — while winterizing your boat may be tedious, everything you need to do is relatively easy and cheap to execute.

Let’s take a look at everything you need to know about winterizing your boat and when you really shouldn’t keep it in the water until spring.

When Should You NOT Leave a Boat in the Water for the Winter?

As a general rule of thumb, you should not leave your boat in the water through the winter months if you live on a coast with notoriously brutal winters.

In areas where the temperature gets extremely low and stays low for long periods of time, winterizing your boat may not be enough to keep it safe. If this climate sounds like yours, opt to store your boat out of the water until spring.

Just as well, if you’re not able to properly winterize or at least cover your boat over the winter, you should do what you can to place the boat in storage.

How to Winterize a Boat Still Parked in Water

Winterizing your boat takes quite a few important steps, but you’ll need to start by understanding the difference between seawater and freshwater when it comes to boat storage.

Seawater vs. Freshwater

Seawater and freshwater have two different freezing points, though they aren’t that far apart. The freezing point for fresh water is about 32 degrees F and the freezing point for saltwater is about 28.4 degrees FOpens in a new tab..

This is more or less negligible when it comes to storing your boat in water over the winter — but when it comes to storing your boat in saltwater or freshwater for an extended period of time, there are some individual precautions to take for each type of water.

Freshwater is often cleaner and can generally be better for your boat’s condition when it comes to storage, as there are fewer minerals in freshwater than in seawater.

However, blisters and temperature can be a concern with freshwater.

Blisters typically happen when a boat is stored in water for a significant amount of time, causing the gel coating to disintegrate. Just as well, freezing temperatures can cause damage.

Freezing can be prevented with antifreeze (more on that later in this guide) but the gel coat disintegration can be prevented by giving your boat a fresh coat of epoxy in the fall.

For saltwater, you’ll mainly have to deal with barnacles and high salt concentrations. Saltwater can reduce the lifespan of manifolds and barnacles can cause significant hull damage.

Prevent this by cleaning the bottom of your boat before and after winter as thoroughly as possible.

The Potable Water System and Antifreeze

Your boat’s freshwater and sanitation system will need to be drained before winter hits, as it will definitely freeze and could possibly cause significant damage to the internal components of your boat.

Unless you drain all of the water out of your boat and replace it with a type of antifreeze, your water lines could be permanently damaged.

Prepping your potable water system only takes three steps:

  1. Open all of the faucets on your boat and launch the freshwater pump. Let the faucets run until the entire tank is dry. Close the faucets and disengage the pump.
  2. Pour around 4-6 gallons of non-toxic boat-specific antifreeze into the potable water storage tank.
  3. Turn on your pump and open the hot water fixture that is the furthest away from the pump. This will make the antifreeze flow into your water heater. Once antifreeze begins to come out, turn the pump off. Do this step again for each fixture all the way to the fixture that is closest to the pump.

If you have a water heater, you can also use a water heater bypass winterization kit. This helps you isolate the water heater so it can be drained separately

Notes for Sailboats

Sailboats don’t require too much in the way of special over-winter care. Just make sure your sails are properly taken down before storing it for the winter.

Change the Oil and Oil-Filter

There are a lot of acids and mildew that are leftover in a boat’s crankcase after winter.

These elements can pit bearings and damage other important engine parts. To avoid this, change your oil right before you lay up the boat for the winter. We’d recommend doing this as the final step.

To do this, run your engine for a minute or two to thin the oil out. This results in much better debris absorption.

Then, shut off your engine, change the oil completely, and change the oil filter as well. Then, restart your engine and run it for a minute or so to circulate the clean oil.

This would also be a good time to check to make sure that your new oil filter is not leaking anywhere.

Cover the Engine Air Intake

When you’re finished up your winter boat prep, make sure that you cover the engine air intake with a tight plastic bag. You can also purchase specially-made vinyl coverings that easily snap over the intakes on the outside of your boat’s hull.

Starting the Boat Back Up in the Spring

Once spring arrives, you won’t be able to simply jump into your boat after three or four months.

You’ll need to put it through a winterization process to make sure your boat is in good condition after storage.

This, like winterization, is a simple process! Simply follow these steps:

  1. Change all of your boat’s batteries and install them if needed.
  2. Clean out terminals and cable ends.
  3. Test all electronic components, especially the bilge pump float switch.
  4. Drain the antifreeze from your water system and use a special disinfectant to properly flush all traces of chemicals from your water system. You’ll need to pressurize the system and unlock each faucet one at a time until clean water begins to drain.
  5. Check your engine oil level and for oil leaks around the bilge.
  6. Remove exhaust coverings.
  7. Follow proper protocol for starting up your boat.

And now, you’re ready to start your boat’s engine!

Keep in mind that some smoke may clear from your exhaust pipes this is normal and caused by fogging oil. You’ll want to run your boat at idle speed. Then, check each of your fash gauges for any signs of issues.

Your steering system might be a bit tight as well. Listen for any signs of anything abnormal and shut down your engine and ignition to do additional checks before taking off.

Consider hiring a boat servicing company to conduct a thorough inspection of your ignition system and engine.

Lastly, give your boat a good wash and a few coats of wax. You’re ready to go!

How was our guide to winterizing your boat? Tell us what you think in the comments section below!

Captain

I'm Chuck (the Captain). I'm passionate about my outdoor space and love sharing my experiences with the world at large. I want Captain Patio to become the best place on the internet to find, share, and learn about all things patio-related. When I'm not keeping up my content schedule, I'm spending time with my wife and two kids (usually on my patio!).

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