8 Tips For Removing Barnacles From Your Boat's Hull

Removing barnacles is challenging enough, but it can be even harder to do without damaging your boat's hull. Barnacles encrust your boat's hull as they invade it and make it their home. 

Boat hull barnacle removal tips

Getting rid of them without damaging your boat’s hull can be an arduous task, especially if it’s a fiberglass hull. Here are 8 tips for safely removing barnacles from the hull of your boat.

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1. Protect Yourself

Always wear gloves when scraping barnacles because their shells will cut through your skin like a razor.

Boat hull barnacle removal safety gear

Bacteria on barnacles, algae and other marine growth on the hull can easily infect cuts. Wear gloves, eye protection and a mask to prevent tiny bacteria-covered particles of barnacles and algae from getting in your eyes, nose and mouth while scraping or pressure washing. If you use acid to remove barnacle husks, wear a respirator capable of filtering acid gasses, a full-face protector, acid-resistant gloves and full-body coveralls.

2. Go Slow and Steady

It's normal to want to remove barnacles off your boat as quickly as possible, particularly if the infestation covers much of or the entire hull. 

Boat hull marine growth barnacle removal

However, working fast and without precautions increases the risk of damaging the hull. By working steadily and taking care not to damage the hull, you’ll take a little more time to get it done without having to worry about repairing or refinishing the hull afterward.

3. Don’t Let Barnacles Dry

If barnacles are allowed to dry out, their bond to the hull becomes much stronger and it makes them much harder to remove. 

Fiberglass boat hull barnacle removal

To prevent the barnacles from drying, don’t lift your boat out of water until you are ready to start removing the barnacles.

4. Pressure Wash Parallel to the Hull  

When using a pressure washer to remove barnacles, always spray at a shallow angle that is as parallel as possible to hull. 

Boat hull cleaning barnacle removal

The goal is to pry the barnacles off the hull, not smash them from above, so spray at a very shallow angle to get under the edges of the barnacles. Don’t aim the pressure washer at a 90-degree angle directly at the hull, as doing so can easily damage the gelcoat and the fiberglass beneath it.

5. Scrape With Care

Scraping the barnacles poses the biggest danger to your boat's hull, so be very careful when using a scraper to remove them. 

Boat hull barnacle scraping

Using a plastic scraper or wooden spatula greatly reduces the chances of scratching or gouging gelcoat. If the barnacle growth is so severe that you have to use a metal scraper, round off the scraper’s corners and dull its leading edge with a file or sandpaper before using it. Work the scraper across the hull as parallel as possible to the surface to get it under the edge of the barnacle. Don’t use the scraper at an oblique angle to avoid damaging gelcoat and fiberglass.

6. Protect the Trailer

Cover your trailer with plastic sheets before barnacle removal to prevent scratches to the paintwork or powder coat from pieces of barnacle shells.

Boat cover

If you’re using oxalic or phosphoric acid-based hull cleaners, or muriatic acid to remove barnacle husks, you’ll definitely need to protect your trailer with plastic sheets. Acid corrodes metals and plastics, including nylon, polyurethane, or rubber rollers and bunk guides/slides, and the galvanized steel used to make your trailer. Muriatic acid will also damage a trailer’s paint or powder coat.

7. Prepare for Hull Maintenance

With your boat out of the water and the hull cleared of barnacles, now is an excellent time to do any other maintenance work to the underside of your boat. 

Boat hull maintenance barnacle removal

Zincs or anodes can be changed out, and thru-hull fittings and sterndrive or I/O props should be inspected and replaced if necessary. Plan ahead and buy the replacement parts you’ll need to service the hull and underside while your boat is out of the water and dry.

8. Prevent Future Barnacle Growth

Once the barnacles are removed and the hull is clean, it’s best to either wax the hull or paint it with anti-fouling bottom paint

Boat hull anti-fouling paint

Either treatment adds a protective layer to the hull and helps prevent future barnacle and other marine growth invasions.



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