Underwater Boat Hull Cleaning

Consideration should be given to using bottom paints that do not pollute our environment. Frequent underwater hull cleaning can enhance vessel performance and protect it from the elements such as marine growth and corrosion. Underwater hull cleaning should be guided by BMPs that will clean a vessel in such a way as to protect and preserve the bottom while causing minimal impact to the environment.

Most vessel bottom paints contain copper (CU). Copper will leach into the water. This leaching may be toxic to marine organisms. Aggressive hull cleaning methods may cause increased copper released into facility’s waters. Make sure your hull cleaner follows the label and recommendations provided by the paint manufacturers.

Boats can carry invasive species on the hull, in bilges, bait tanks and seawater systems. Aquatic species such as, Quagga and Zebra Mussels can harm native marine life, damage structures and shorelines, clog water lines and are very hard to control. We encourage marinas and yacht clubs to educate their staff to the crucial role in preventing and detecting aquatic invasive species. They also need to educate boaters on why it is important through the use of simple steps to avoid spreading these aquatic invaders. The key messages are: Inspect, Remove, Dispose and Report any Invasive Species.

Marina and Yacht Club Best Management Practices

  1. Recommend the use of nontoxic and legal hull paints to reduce the possibility of contamination when performing hull cleaning.
  2. Properly functioning anti-fouling paint will repel all hard growth and requires only occasional light wiping with a soft cloth to remove slime. Aggressive cleaning of anti-fouling paint using tools such as scrubbing pads and powered rotary brushes will shorten the effective life of the paint significantly, and should never be used. Aggressive cleaning of this nature increases the amount of copper entering the water column and sediment. The boat should be hauled and recoated with fresh anti-fouling paint before this style of cleaning is ever required.
  3. Remember:
    NO Scrapers (metal/plastic/wood).
    NO Abrasives (sandpaper/cleanser/soft scrub).
    NO Scotchbrite®/3M® pads.
    NO Powered Rotary Brushes.
    USE soft cloth or fleece mitt only.

Boater Best Management Practices

  1. Ensure hull paint is properly applied and maintained to protect the hull from fouling organisms and thus improve your boat’s performance.
  2. Wait 90 days after applying new bottom paint before underwater cleaning.
  3. Schedule regular hull cleaning and maintenance to reduce the build-up of hard marine growth and eliminate the need for hard scrubbing.
  4. Regularly scheduled gentle cleaning will also increase the effectiveness of the antifouling hull paint and extend its useful life.
  5. Use, or ask your Hull Cleaning/Maintenance Service to use, Underwater Hull Cleaners’ Best Management Practices. Ask your service to monitor the work of the divers that they hire or subcontract to ensure they are using BMPs.
  6. Repair paint bonding problems at haul out to avoid further chipping and flaking of paint in the water.
  7. Use, or ask your diver to use, non-abrasive scrubbing agents, soft sponges or pieces of carpet to reduce the sloughing of paint and debris.
  8. Boaters are encouraged to use boat hull cleaning companies and individuals that practice environmentally friendly methods.
  9. Encourage divers to use different types of pads when necessary to properly maintain a vessel’s bottom paint (example: In many cases surfaces close to the waterline are more susceptible to higher growth rates therefore you need to use different pads in order to properly remove marine growth and corrosion. Likewise, a softer pad can be used for the rest of the vessel to maximize hull performance and optimize the lifespan of the paint.)
  10. Boater should notify hull cleaner as to what type of bottom paint was used and when the bottom was last painted.
  11. Invasive Species
  12. Boats can carry invasive species on the hull, in bilges, bait tanks and seawater systems. Aquatic species such as, Quagga and Zebra Mussels can harm native marine life, damage structures and shorelines, clog water lines and are very hard to control. We encourage marinas and yacht clubs to educate their staff to the crucial role in preventing and detecting aquatic invasive species. They also need to educate boaters on why it is important through the use of simple steps to avoid spreading these aquatic invaders. They key messages are; Inspect, Remove, Dispose and Report any Invasive Species.
  13. To prevent the spread of Quagga and Zebra Mussels, download and provide copies of the aquatic invasive species best management practices for boaters to your staff and tenants. The website is: http://www.dfg.ca.gov/invasives/quaggamussel. For additional information and regional contacts, go to http://ucanr.org/sites/coast/Quagga_Mussel_Invasion/.

Score Sheet – Page 4: Underwater Boat Hull Cleaning


Sidebars represent changes incorporated in CMP Manual_revised 2_28_12.