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Mice can be a problem for cars or boats during winter storage. Whether the boat is stored  inside or out it shouldn't be too difficult to see how a mouse can find its way inside, even if the cabin and lockers are buttoned down tight. Imagine the mouse climbing up the trailer frame or tarp rope, into the scuppers or the exhaust pipe, chewing through a rubber hose (on a C&C 27, there is a rubber hose connecting the floor drains and the opening in the transom and also a rubber section of the exhaust pipe after the water inlet) and getting into the locker and/or engine compartment. After that I suspect, as most others, that a mouse could crawl from the engine compartment, through the bilge and out through the access hole in the floor boards, or wherever. Once inside the cabin they would have access to a whole winters supply of cushions, life jackets, curtains, wood trim and food. Food is probably the number item that attracts mice. The second one is wood matches, especially the strike anywhere type. I've heard that it's the sulphur that attracts but I have no idea why.

Squirrels can sometimes be a worse problem than mice if you store your boat at your lake lot. They are simply looking for a warm secure home and will make a huge mess by chewing up cushions. Many older boats in my neighborhood have major cushion damage from squirrels. I am very reluctant to leave my hatch open during the winter for this reason. They can't get in anywhere else. Around my cabin squirrels are relentless at getting underneath the cabin and pulling down floor insulation. Regrettably, the only solution I've found is to shoot them as poison is a risk to pets and I don't want the squirrels dying and rotting under the cabin.

Cats have a unique way of occupying a boat stored on an acreage.  They can get into places that will surprise you.  I don't blame them for curling up in a warm spot out of the wind but do they have to claw at the lines when they wake up?  To put an end to their playing I removed all lines and slipped a heavy duty nylon bag around the mainsheet which I can't remove.  Nylon bags are quite inexpensive at Ikea and can be used for a myriad of storage items during the summer.  Then I placed a small cushion in the cockpit to encourage it to sleep there.  It worked.  One time the cat climbed inside the boat and it was some hungry when I opened the boat.  Better than dying inside I guess.  After this experience I now leave the forward hatch cracked open only a 1/4" with a heavy weight on top to prevent lifting and a bug screen to keep the leaves out.  Never had any critter inside since. 


  1. Remove all food, vacuum the floor and plug all through hull holes with a bronze wool pad. Mice can't chew through it. Remember to remove them in the spring. 
  2. Take a tip from the folks in the car clubs who say, "NOT to use moth balls as you will never get the smell out." Some of them use a bar of Irish Spring soap. You grate a bar of soap, spreading the shavings around on the seats, floor, etc. It must be the original Irish Spring with the green stripes. The shavings are effective for about a year or until the colour changes. Then you have to do repeat the treatment. It also makes the place smell like a fresh Irish morning, sorry! Just couldn't resist. 
  3. If your boat is stored outside for the winter you should cut the grass where the trailer is parked. Cut under and to about a 6' radius all around the trailer. This goes a long way to keeping the mice away from your trailer. I credit this technique with the fact that I haven't had any mice in my boat in the 25 years I have stored it outside. The rational behind this idea is that mice are reluctant to expose themselves to a predator by running across an open area. Consider this for instance, ever wonder why mice have eyes on top of their head? They can look almost straight up. My theory is that they're on the lookout for hawks ALL the time.  Once the snow is settled in they dig tunnels to access fresh grass for food and insulation. There should be very little of that around the trailer. Besides, without grass the wind and ground heat will keep the snow clear under the trailer similar to under spruce trees. By eliminating the long grass you also eliminate a source of rust for the trailer frame. No dew to contact the steel. 
  4. If you have access to electricity, purchase an electronic mouse repellant device. These plug into 110VAC and emit a high frequency sound that people I can't hear but drives mice nuts. These really work!!! ...but apparently only line of sight. You can buy them at Canadian Tire but they are cheaper at Costco where they come in triple packs.
  5. If you already have mice, use glue boards to catch them. You will have to check the boards frequently as a rotting mouse carcass is very smelly.
  6. One final note, a whole generation of mice are born and die under the snow each year without ever seeing the sun. It's warm and bright down there. Just thought you should know. 

Here are some other good ideas concerning winter boat storage:

Remove as much weight from the boat as possible, especially in the unsupported ends.
Open all cupboards and lockers to thoroughly dry and clean them before freeze up.  Remove all contents and especially food.
Wipe up any water in the bilge.
Drain the water from the water tank.
Drain your Porta-Potty.  Its OK to store it on board the boat if it is bone dry. Use 
Hang lines out to dry. Wash them in a pail with mild soap if required.  Makes them nice and soft again.
Remove sails from the boat, fold them properly and hang them in their stuff bag.
Cover the hull with a tarp, leaving the ends open for ventilation.
I leave the hatch cracked open for some ventilation, but small enough to keep a cat out. One of the problems of storing a boat on an acreage.  I also remove the knot meter impeller for more ventilation. You have to think long term slow air movement here.  The impeller is stored inside a plastic bag with grease on the O-ring to keep it from drying out.
If you have a hole in the bottom of your mast, stuff a rag in it to prevent the birds or bees from starting a nest in the spring.  A nest or hive can really jam an internal halyard. 
If haven't yet figured out how to prevent bees from starting a hive inside the trailer frame.  They are just too small to plug all the hole sin the frame.
Remove the battery and connect a "smart charger" to it.  Leave it on ALL winter long.


Just before haul out, disconnect the fuel line and to the outboard and run the engine till it dies of fuel starvation. This ensures that no varnish accumulates in the carburetor bowl.  Do this at the lake.
Take a note of how solid and strong the stream of cooling water is flowing out of the engine.  A sputtering stream is an excellent indication to replace the impellor. The seals are weak. You could also have debris in the water jacket. Never leave an impellor in so long that it starts to break apart, leaving bits of rubber to flow into the cooling jacket. This is sure way to overheat an engine. 
Drain the old gear case oil and replace it with new each Fall.  This eliminates the possibility of splitting the gear case due to freezing water over winter.
Spray fogging oil into the cylinders to prevent corrosion.
Clean the spark plugs, including the ceramic insulator.
Drain the water from your engine cooling system.  It should drip dry if the engine is stored vertical on a stand. I also like to apply compressed air at about 30 psi to blow all passages dry.
Place the shifter in forward to prevent turning the engine over with the starter cord. This will prevent tearing the seals off a dry impellor, rendering it useless after ONE pull.
Add some fuel stabilizer to the gas tank to prevent varnish buildup which can plug the carburetor jets, etc. 

Ideas contributed by Jim Spalding, Doug Murray and Bob Schimmel.

If you would like a subject discussed at a monthly meeting or want to post something on the AOSA web site then email the web master. Site last updated on 07 October, 2008.