Bottom cleaning, while important for speed and upkeep of a boat, has two possible risks:

As a regatta host, you should be aware of the effect that a marina full of bottom cleaning can have on your local waters. During your event, request that racers refrain from scrubbing their painted hulls to reduce the impact. You can also provide a shoreside site with a runoff capture system for those who wish to clean their hulls during the race.

 

Boat without bottom paint may be permitted to scrub their hulls in the water, but only on the condition that they left their homeport with a clean hull.

 

Boats are a good mode of transportation not only for people, but also for the critters that can hitch a ride on your hull. When traveling to a regatta, it is important to be mindful of the possible invasive species you might take with you, introducing them to a new habitat. Invasive species can thrive in an unfamiliar environment where they may have no natural predators, and can outcompete other native species for food and space, disrupting a lake, harbor or river's delicate balance. For this reason it is important to scrub your hull clean before transiting to a new location, whether you are hauling out of one lake and moving to another, or sailing from port to port along the coast.

 

Anyone who sails in any freshwater lakes or rivers in many parts of North America is probably familiar with the zebra mussel (Dreissena polymorpha). Originally native to Russia, it was introduced to the U.S. on the hulls and in the bilges of ships, first appearing in the Great Lakes, and spreading as far as the Mississippi and Colorado Rivers. Their ability to proliferate and feed reduces the amount of oxygen available to other species, often creating "deserts" of many once-healthy ecosystems.