With the Black Flag insect repellent, I find the best way is to mix 2 ounces of it with a gallon of water, and then spray using a small water spraying bottle. It doesn’t stain or smell and won’t wash away easily. In most cases, that leaves my pontoon boat bug free, with no flies, bugs, or spiders.Click to see full answer. Also question is, how do I keep spiders off my boat? Try mothballs as a spider repellent (but be cautious) 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.Also Know, does incense repel spiders? Lighting a stick of incense will always keep spiders and pests away, since they cannot bear the burning smell. In general, you can put cedar blocks around, especially in areas that tend to attract these bugs. Thereof, does smoke deter spiders? Tobacco. Spiders are not big fans of tobacco, and you can find loose leaf tobacco at smoke shops and even some grocery stores. You can also make tobacco balls by mixing the leaves with flour and water and placing them around your house to repel spiders.How do I keep bugs off my boat? Below are some of the natural ways to keep bugs away from your boating trip: Keep everything tidy and clean. Cleanliness is imperative on every boat. Use repellents with natural ingredients. Use vinegar. Always close windows and doors at night and at dawn.