How to Protect Your Boat from Spiders

Of all the creepy-crawlies that may come aboard your boat, spiders are often among the least welcome. These many-legged miniature monsters are especially common during summertime when the warm weather brings with it an abundance of food – namely, other bugs. Despite their essential role in controlling populations of flies, mosquitoes and other bothersome insects, a spider infestation is the stuff of nightmares for most people!


Whether you’re arachnophobe or not, large numbers of spiders can seriously mess up the interior of your boat. This is because, besides leaving webs everywhere, spiders also poop a lot.

Their grayish, brown or black droppings can often be found in corners and on seat covers of boats and will look like tiny dots.

If wiped up immediately, spider poop is no problem. However, if left for long periods of time, these tiny droppings will harden like concrete to form a crust that’s almost impossible to shift. Even if you do manage to chip away at the mess, spider poop can leave stains that permanently damage the aesthetic of your boat.

Having large numbers of spiders on your boat can even be a serious health risk to you and your shipmates. Many spider species common to North America can deliver a nasty bite and some, such as the notorious Black Widow, can even be fatal.

So, the big question is – how can you protect your boat from spiders? To avoid your boat becoming a web-ridden hellscape, try the following spider control methods for your boat.

How can you protect your boat from spiders?

Spider spray for boats

One of the most effective ways to cut the number of spiders on your boat is to apply an effective spider repellent spray. The best of these are designed to take down both spiders and other types of insects, as this also eliminates their food source and reduces the likelihood of them coming aboard.

But what sort of spray should you use?

It may be tempting to reach for the insecticides, but these are not recommended for use on boats. Devices such as foggers and bug bombs may work OK at home, but in small, confined spaces the harsh chemicals in these devices could damage the interior of your boat. Even if they don’t, you may find that you’re stuck with the smell for weeks, and the chemicals could wreak havoc in the surrounding aquatic ecosystem.

Instead, use a spray that’s formulated using natural ingredients, such as peppermint oil, geraniol or rosemary oil. These plant extracts effectively repel spiders (and kill insects) without harming the environment, for an effective yet low-impact treatment.

Clean and vacuum your boat thoroughly and regularly

One good way to reduce the number of spiders on your boat is to remove them before they get a chance to breed. By regularly cleaning and vacuuming your boat, you’ll be able to turf out any eight-legged intruders, while removing any eggs or webs.

You should take everything portable out of your boat and get into the nooks and crannies with a vacuum cleaner at least once every few months to keep your spider population minimal. Keeping your boat clean and tidy can also help to reduce insect numbers in general, removing the spider’s main food source and deterring them from moving in.

Install screens wherever you can

Get to work sealing up as many gaps and openings around your boat as possible if you want to keep spiders away. Arachnids can squeeze themselves through tiny gaps to get inside and will often do so when looking for a place to nest. By installing screens wherever you can, you can create a physical barrier between your boat and the spiders, significantly helping to reduce the number that makes it inside.

Spider netting

The principle of spider netting is the same as that for screens; it’s a way of creating a physical barrier to prevent spiders (and their droppings) from landing on your deck.

The advantage of using netting over screens is that it’s easier to achieve full coverage (and therefore more complete protection) of your boat.

This is because spider nets can be custom made to perfectly span the width and length of your boat, leaving no gaps for spiders to sneak in.

An added bonus of using netting is that it can also provide some protection from birds, as they won’t want to land on such an unstable surface. This means not only fewer spiders on your boat but less bird poop, too!

Be vigilant about food waste

If you spend a lot of time on your boat, you probably come aboard laden with snacks and sandwiches. If you do eat or prepare food on your boat, it’s important that you take care to dispose of any food waste and crumbs thoroughly. Morsels of food left lying around can attract flies and other insects which, in turn, provide a steady food source for spiders.

Keep your boat clean and bug-free to avoid tempting spiders inside!

Try mothballs as a spider repellent (but be cautious)

Mothballs are an age-old method of repelling all sorts of creepy crawlies and they work on spiders, too! Leaving an open jar of mothballs on your boat can help to keep spiders away but be careful about how you use them. Mothballs release insecticidal vapors into the air, which can be harmful if inhaled. If you do decide to use mothballs as a spider repellent for your boat, use them only when the boat is unoccupied and make sure to air out the interior completely before re-entering. This method is best suited for when you plan to leave your boat deserted for several months, perhaps during winter.


Spiders are rarely welcome, but boats often make attractive homes for arachnids. Spiders will often come aboard in search of food (namely insects) and a place to nest, particularly during the summer months when their numbers boom. Protect your boat from spiders by keeping it clean and crumb-free, invest in spider nets or screens, and consider the use of a (natural) spider spray!



Thank you for this interesting article. Do you have any advice about controlling those spiders that take up residence on the outside areas of your boat? We are inundated this year. Thank you.


    We suggest taking a look at spider sprays that are water-resistant, while also not toxic to the aquatic life forms.

Geoff and Anna Mann

We was told that placing conkers around the boat will help keeping spiders away . Is this true ?


    There is such belief, however, there hasn’t really been much evidence to support the claim. We suggest using other methods.

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