Whether your boat is in the water or stored outdoors, there are a variety of critters that can get into different parts of your boat and do expensive damage.
A boat that's stored outdoors can be an inviting nesting location for mice, rats and squirrels.
Larger animals like raccoons sometimes take shelter under boat covers.
Mice and other small critters can get through the various crevices of your boat and then chew through wires and also shred softer materials like vinyl. They also make a mess by urinating and defecating.
How do you stop these animals from costing you money and causing a lot of frustration?
There are a number of ways to keep these intruders from ruining parts of your watercraft. No one method is 100% effective. It's often a matter of setting up several layers of defense.
Barriers to Entry
One layer of protection is to prevent access through different entry points.
Plug all gaps around your boat, such as the propeller shaft, to prevent animals from entering through these openings.
Mice look for any opening to squeeze through, so make sure that you cover up all openings as best you can.
You can use a silicone sealant, expanding foam, or galvanized steel mesh to cover up potential entryways into your craft. Some people have had success using aluminum foil and steel wool.
Note: If you have never used expanding foam before, make sure to experiment with it first, as it expands more than most people think.
Ultrasonic Devices
Ultrasound is waves with frequencies over 20 kilohertz — outside the range of human hearing.
High high frequency emitters can deter animals from getting near or into your boat.
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These come in both plug-in and battery powered models. Many of them also include a strobe light, which is an additional deterrent.
Keep in mind that if you already have a rodent problem in your boat, ultrasonic devices will not work immediately. It can take several weeks for a rodent to decide that they've had enough and to look for another place to call home.
Because of this, it's important to change your batteries before they wear out.
Water Sprayers
You can also purchase motion activated sensors which will spray animal intruders with water when they get too close to your craft.
The sound and shock of being sprayed is enough for most critters to head in the other direction.
Havahart makes a motion activated sprayer called the Spray Away.
Moth Balls
Moth balls are another way to keep critters out of your boat.
Moth balls are effective in keeping animals out because most mammals, insects and other creatures find the scent of these balls unbearable.
Moth balls can be put in small bowls and placed around different parts of your craft and inside compartments.
The downside to moth balls is that the scent is also offensive to humans.
Dryer Sheets
As a more pleasant smelling alternative to moth balls, some people swear by scattering dryer sheets all around the inside of their boat. Popular brands include Bounce and Breezy.
A few people have reported mice using dryer sheets as nesting material.
Peppermint Oil
Peppermint oil is a deterrent to some animals. You can pour drops of oil onto cotton balls and distribute them around your boat.
The downside to this method is that you need to continually re-saturate the cotton balls with oil.
If you get a peppermint plant, you can use the leaves instead of a store-bought oil. Put the leaves in bowls along with rags or old socks.
Heavily Scented Bar Soap
Irish Spring is a brand of soap that can deter animals from getting into your boat.
When storing your boat for winter, cut bars of Irish Spring into smaller pieces. Place the pieces around the interior of your boat.
This has worked for some people, but others have reported mice actually chewing the soap.
A Pet Cat
If your boat is stored outdoors on your property, an indoor/outdoor pet cat is one of the most effective ways to keep mice and other rodents away.
Of course, you need to be willing to own a cat, which is not everyone's preferred pet.
If All Else Fails
Aside from a sentry cat, storing your boat indoors is the single most effective way to keep critters away from your boat.
And, of course, indoor storage better protects your boat from the elements.