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Making Dollars and Sense of Nontoxic Antifouling Strategies for Boats

The Issue

Plant and animal growth on boat hulls increases drag, which slows sailboats and increases powerboats' fuel consumption (and related pollution). Most of the antifouling paints that boaters apply to prevent the problem slowly leach copper, which keeps marine organisms from attaching to boat hulls. However, the copper has accumulated in coastal boat basins to levels that exceed federal and California standards of 3.1 ppb. The copper is harmful to marine life, especially molluscs, crustaceans, echinoderms and phytoplankton.

What Has ANR Done?

In 2002, Marine Advisor Leigh Johnson and Program Representative Jamie Gonzalez collaborated with UC San Diego Economics Professor Richard Carson to evaluate costs of using copper versus nontoxic boat bottom coatings. They determined that, because of costs for stripping old paint and given boat repair yard capacity, it would take at least seven years and $20 million to convert all San Diego Bay boats to nontoxic paint. Typically, old layers of paint must be stripped after 15 years. Extending the conversion period to 15 years would allow old paint to be stripped when it was ready, reducing the total conversion cost to $1 million -- a 95 percent savings. These findings were submitted to California Department of Boating and Waterways, which forwarded them to the California Legislature pursuant to Senate Bill 315, which mandated the economic study.

Johnson and Gonzalez have used their findings to educate 3,400 boat owners, boating and coating businesses, agency staff, policy makers and other scientists. They continue to extend information and their Web site http://seagrant.ucdavis.edu has become an internationally recognized source of research-based information.

The Payoff

Cutting Costs of Cutting Pollution

In 2006, the California State Water Resources Control Board approved a Total Maximum Daily Load program for copper from boat hulls in Shelter Island Yacht Basin of San Diego Bay. Discharges of copper from boat bottom paints must be reduced by 76 percent over the next 17 years. Instead of a short and expensive timetable for converting to nontoxic hull coatings, boat owners will have a 2-year education period, followed by a 15-year conversion period as recommended by Johnson and Gonzalez' research. This should cut costs to convert to a nontoxic system for protecting boat bottoms by 95 percent.


Supporting Unit: San Diego County

University of California Cooperative Extension - Sea Grant Extension Program
5555 Overland Avenue, Suite 4101
San Diego, CA 92123
Phone (858) 694-2852