Winterizing a Boat Checklist: How to Prepare a Sailboat for Winter Storage
Laying up your boat? Wondering exactly what steps you need to follow to properly prepare a sailboat for winter storage? So were we. This is our complete Winterizing a Boat Checklist.
Following our first season of sailing in the Mediterranean, we prepared for our first sailboat winterization. As we didn’t plan to live on it over the winter, we opted to dry-dock it on hard stands in a boatyard on the island of Corfu, Greece.
Being novices, we assumed the boat would be pulled out, we would lock it up, and head off to the airport, only to return 6 months later to a boat in pristine condition. But just in case there were one or two things I hadn’t considered, we decided to put the call out to Facebook groups to check if there was any advice on storage tips.
Well, it turns out, sailboat winterization is a little more complicated than mooring and jetting off. Laying up a sailboat for winter is quite an involved process designed to protect and maintain each system, and piece of rigging on your boat through the winter. By failing to prepare your boat for winter properly you risk coming back to a boat with engine problems, faulty electric systems, damaged rigging, and potentially a smelly cabin filled with mold and vermin.
We received so many replies on Facebook listing things to do and check, we realized we were going to need to set aside at least one busy weekend to properly prepare the boat for storage.
Based on the intel gathered from helpful boating enthusiasts, websites, and YouTube, I’ve compiled this comprehensive winterizing a boat checklist, detailing each step required for preparing a boat for dry-dock and storage.
n.b. This checklist was prepared with the Mediterranean climate in mind. If you’re storing your boat somewhere with long cold winters below 0°C, then different/extra steps may be required to protect the engine and plumbing with antifreeze.
Winterizing a boat checklist: 16 Quick Steps to Prepare a Sailboat for Winter Storage in the Mediterranean
Step 1: Clean the Boat Thoroughly
Time: 3 – 4 hours
Difficulty: Moderate
Like you’ve never cleaned before. Systematically move through the boat cleaning from front to back. Remove everything and clean every nook, crevice, and cranny to make sure the boat is free of dust, debris, and above all food. Wipe down surfaces with antibacterial or a mix of water and vinegar.
After you have cleaned the inside, move to the outside and clean as you have never cleaned before. Don’t forget to clean the storage compartment and rinse everything down with fresh water to remove all salt particles which cause corrosion.
Step 2: Take Down the Sails
Time: 30 minutes
Difficulty: Simple
Sails left in the sun and weather will age much quicker than sails properly stored.
Ideally, choose a calm dry day to take down your sails. Pull them out, release the sail halyard and flake the sail as it comes down by making ‘accordion folds’. Alternatively, if you have more storage space, you may choose to roll your sail up for storage to avoid creasing. Once folded or rolled, bag the sail and store it below deck.
We took down our furling genoa, it was clean and dry so we didn’t need to wash it. We folded it and bagged it and put it below deck. Our mainsail furls into the mast so we furled it all the way up and covered the last exposed triangle of sail with some canvas to protect it.
While many people believe that the mast is as good a place as any to store sails for the winter, many others believe that both sails should be taken down, washed, dried, folded, bagged, and put down below deck for winter.
Traditional, vertically hoisted sails should be taken down, folded, and stored inside the boat.
Step 3: De-Rigging
Time: 30 minutes
Difficulty: Simple
Any running rigging left on the deck exposed to weather will age more quickly than if taken down and stored in a cool, dry place. That being said, much of the deck can be protected using boat covers and you’ll need to weigh up the pros and cons of taking off every piece of running rigging and re-rigging it all next season.
At the suggestion of many sailors, we elected to
- Take down the mainsheet and genoa sheets, soak them, dry them and store them below deck,
- Take down blocks on the deck
- Finally, we replaced exposed halyards with ‘mouse line’, 3 – 5 mm polyester rope tied to the ends of the halyards. This allows the ropes to be pulled back into the mast during the winter and retrieved next season, saving them from exposure to the weather.
All ropes that were removed were soaked in water with fabric softener to remove salt residue and to avoid returning to stiff ropes in the new season.
Step 4: Prevent Fuel Spoilage
- Time: 30 minutes
- Difficulty: Simple
On the way to the dry dock, stop by a fuel station and fill the fuel tank to the brim. At the same add diesel biocide and stabilizer to prevent the growth of diesel bugs and lengthen the diesel’s shelf life.
Engine operating manuals and common wisdom says that by filling the fuel tank to the brim no condensation can form in the tank and add water to your fuel supply during the off season.
While this point of sailboat winterization is contested amongst sailors with many believing this old wisdom disproved, we figured it was better safe than sorry and swung by the petrol station on the way to the boat yard.
While we filled up the tanks we also added a stabilizer and antimicrobials to help the diesel last longer and to slow the growth of diesel bugs.
Step 5: Pack Up the Tender
Time: 30 minutes
Difficulty: Easy
One of the easiest steps to sailboat winterization is to pack up the tender. Clean the inflatable tender thoroughly with soap and a scrubbing brush, rinse, dry, deflate, fold, bag, and store below deck.
Step 6: Give the Engine Some Love
Time: 1 hour
Difficulty: Difficult
Drain and replace engine oil, replace filters (fuel filters and oil filters), and spray the internal engine components with fogging oil to protect them from corrosion.
Winterising the motor in many places means preparing the boat for sub-zero conditions, this isn’t an issue in the Mediterranean. You won’t need to flush your engine with anti-freeze but you do need to flush the engine with fresh water to avoid corrosion over the winter.
To do so:
- Close the engine seacock
- Fill a bottle or watering can with 10 or 12 liters of fresh water
- Find the engine’s seawater filter
- Start the engine
- As the seawater filter begins to drain slowly add fresh water until all the water has been used or water starts backing up in the seawater filter.
Step 7: Don’t Forget the Outboard
Time: 15 minutes
Difficulty: Easy
Flush the outboard motor with fresh water and run the petrol out.
- First, connect a freshwater hose to the outboard water intake using “earmuffs”
- Turn on the hose and start outboard
- Let the outboard run out any fuel left in it
- Wash down external housing with a hose
- Remove the engine cowl and spray internal components with fogging oil to displace water and prevent corrosion.
Step 8: Thoroughly Clean the Bilge Until Spotless
Time: 30 minutes
Difficulty: Simple
- Using a bucket and a rag or an old sponge get rid of any fuel, oil, or debris in the bilge.
- Using a cloth or sponge scrub the bilge with warm water and eco-friendly boat soap.
- Start bilge pump and flush bilge and bilge pump with fresh water
- Once the water has drained, dry out the bilge with a towel or cloth.
*If you have a very grimy or oily bilge you may need to use a heavy-duty cleaning product in which case cleaning may need to happen on land where you can collect the bilge output.
Step 9: Flush Toilet System
Time: 10 minutes
Difficulty: Easy
Use a 50/50 mix of vinegar and water added to the head and flush it through to clear any salt water from the system.
Step 10: Treat Water Supply
Time: 15 minutes
Difficulty: Simple
Onboard water tanks should be filled with water treated with a sanitizer like chlorine to prevent the growth of any nasties over winter. When you return, drain and flush the tanks well before refilling them with fresh drinking water.
If you have one, pickle your watermaker for winter as per the manufacturer’s instructions.
Step 11: Remove the Anchor from the Anchor Well
Time: 20 minutes
Difficulty: Simple
The drain in the anchor well can become clogged if unattended, and this could cause the anchor well to fill with water and the anchor and chain to spend all winter submerged.
Lower the anchor and chain to the ground and store them on a wooden pallet. Wash out the anchor well and cover.
Step 12: Protect Your Boat From Pests
Time: 15 minutes
Difficulty: Simple
- First, ensure you have removed any incentives for pests. Make sure there is not a crumb of food on board, and that any dirt and debris have been cleaned from every nook and cranny. Make sure no water can enter the boat, and that no water leaks from can water tanks or plumbing.
- Next, stop ingress. Any chains or lines that run from the ground to the boat for eg. the anchor chain, should be fitted with anti-rat and mouse devices, these can be made using an empty coke bottle.
- To stop pests like bugs, wasps, or even birds from making a home in your vessel block or fill all external openings using rags. This includes exhaust ports, sea cocks, openings in the boom or mast, or any other port or opening in the boat.
- To prevent ant invasion put some grease on hard stands about a foot off the ground.
Step 13: Protect Your Boat From Mold
Time: 15 minutes
Difficulty: easy
Making sure your boat is leak free is an important step on the sailboat winterization checklist. If any seals have given way after the sailing season now is the time to properly reseal.
We found that water was entering our boat from the deck at the mast and where the rear arch was bolted. We sealed these areas with marine silicone sealant.
Once you are sure the boat is free of water, remove any existing mold on surfaces or cushions.
Add vinegar to a spray bottle and hit all moldy surfaces. Allow the vinegar to sit for one hour before scrubbing the mold off with a brush and some soapy water. Allow everything to dry completely.
Finally, spray all surfaces that could possibly attract mold with a 50/50 vinegar-water solution, do not wipe it down to prevent mold from re-growing.
Do not store anything on the boat damp. Make sure everything going on board for the winter is bone dry.
Don’t store mattress cushions flat, store them on their sides to allow as much air as possible to circulate around them.
Step 14: Turn Off All Sea Cocks
…and write notes to remind yourself to turn them back on.
Step 15: Maintain Batteries
Time: 10 minutes
Difficulty: easy
Batteries in good shape will survive winter in the Mediterranean by being fully charged and disconnected. You can disconnect your batteries by disconnecting all wires for the negative terminals of your batteries.
Tape up the now loose negative wires using electrical tape.
Cover permanently mounted solar panels and take down removable panels. Tie up wind generators.
Step 16: Cover Boat for Winter
Time: 20 minutes
Difficulty: easy
A durable winter cover that will protect the boat from sun and rain as much as possible is well worth having.
A boat cover will ideally cover the whole deck and the boom (some people take their boom down for storage over winter). At the very least, the main cover should cover from the transom to the mast to protect the cockpit, instruments, winches, and rigging. In this case, you can also use a separate cover to protect the important items at the front of the boat such as windlass, and forward hatch.
Boat covers are typically made from marine-grade canvas or vinyl.
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Hopefully, we have given you an idea of the jobs you will need to do to correctly prepare a boat for winter in Greece.
But if you think we missed any steps laying up a boat for winter in the Mediterranean, or if you have any questions, let us know in the comments below.
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