Rid your boat of spiders
How can you get rid of the spiders in boat ports without using pesticides?
While a boat cover will deter some of the spiders from heading into your boat, others will still find their way underneath, between the snaps. But spiders are a beneficial species. Orb-weaving spiders, like the ones often found in boat ports, love to take up residence close to water where they can feast on insects that hatch on the water’s surface, such as midges and mosquitoes.
The use of pesticides is a definite no-no, as you point out; however, a daily sweeping may eventually encourage the spiders to move on to a more stable home where their nests won’t be disturbed. The next time you find yourself irritated by a spider-made mess, remember this lovely nature fact: Our native hummingbirds require spider-webs to build their nests. So when you enjoy a tiny hummingbird flitting among the flowers, you can thank your lucky spiders.