How to Clean and Remove Barnacles From a Boat

how to remove barnacles from a boat

Don’t you just wish you beefed up on the bottom paint? Now that the barnacle invasion on the bottom of your boat is in full swing, you’re going to have to get rid of the critters before you can even think about re-applying bottom paint. But since those sticky little crustaceans won’t let up just like that, you’re going to have to get creative.

No, those pesky barnacles aren’t going to come off with a pull here and there. So if you’re wondering how to remove barnacles from a boat without causing any damage, try these surefire methods.

What are Barnacles and Why Should You Remove Them?

Balanus glandula, or barnacles, are a type of arthropod that like to live in shallow tidal waters. They like places with lots of activity since they filter feed, so currents and waves help ensure that they get their fair share of food regularly brought into their territory. That’s also why they like sticking to relatively stable objects like rocks, whales, and yes, even your boat.

But they don’t just grab on. Barnacles use one of the strongest glues in the natural world, with a tensile strength of 5,000 lbs per sq inch + adhesive strength of up to 60 lbs per inch. For that reason, you’re not going to be able to simply pull them off.

Well, they’re just little critters after all. Do you really need to remove them? Although they might not seem like such a threat especially since they’re all shelled up and quiet, barnacles have been known to be one of the most common reasons for boat damages.

The reason why a boat’s hull is designed to be smooth and streamlined is because it improves the boat’s movement through water. These barnacles can change the surface of your boat and cause unnecessary drag, overworking your engine and causing you to burn up more fuel than you actually need.

According to studies by the U.S. Navy, barnacle growth can increase drag on a ship by up to 60%, which consequently increases fuel use by up to 40%. All of that said, it’s really not hard to see why barnacles have no place on the bottom of your boat.

What You’ll Need

Anyone learning how to clean barnacles off a boat will soon learn that it’s a delicate process. Going in too rough could damage your hull, but not using quite enough force or the right technique could hand the victory to the invasive arthropods. So to make sure you complete the cleaning task with flying colors, make sure you have these essentials in your arsenal:

Marine Growth Remover

marine growth remover

Okay, so this stuff isn’t like some magic soap you can spray on so you can just easily wipe off those barnacles. Instead, it works to soften the marine growth’s cling to your hull so you can work them off a little easier.

We recommend the Legend Brands Marine Growth Remover for Barnacles.

Boat Hull and Bottom Cleaner

star brite boat hull and bottom cleaner

Once those barnacles are off, you’re going to be left with a whole lot of marks of where they once were. To make get rid of whatever’s left behind, you can use boat and hull cleaner.

Check out the Star Brite Boat Hull & Bottom Cleaner.



This tool will most definitely come in handy, but it pays to consider whether you need a metal scraper or gentler plastic or wooden one. If you’re choosing to go with metal, it’s imperative that you prepare the lead edge first before you get started.

You can either use the Red Devil Plastic Scrapers or Putty Knife Scrapers from DEKEones.

Stainless Chainmail Brush

stainless chainmail brush

This should help you clear out any barnacle residue that’s left behind after knocking them off. Make sure you have a spare at the ready in case your boat’s hull is too big for just one.

We like the RINGKI Stainless Chainmail Brush with Silicone Handle.

Pressure Washer

pressure washer

If you just don’t have the energy to get rid of those barnacles with a scarper tool, or you want to get the job done faster, you can opt for a pressure washer. Sure, it’s going to be a little more expensive. But it’s definitely an investment for boat owners who do their own maintenance.

We highly recommend the Wholesun Electric Pressure Washer.

Random Orbit Sander

random orbit sander

For really stubborn barnacle marks, a random orbit sander should come in handy. Not only will it get rid of residue, but it should also prepare your hull for that protective layer of bottom paint.

Try out the Black + Decker Random Orbit Sander.

Bottom Paint

bottom paint

Now that you’ve learned your lesson, it’s important that you take the time to apply that bottom paint properly. Don’t forget to use a primer to extend the lifespan of that fresh coat of anti-fouling paint.

Check out the Interlux Anti-Fouling Bottom Paint and don't forget to use Rust-Oleum Primer.

Removing Barnacles With the Scraping Method

This process is ideal for boat hulls that might not have significant barnacle growth. Just make sure you’ve got the whole weekend off and that you’ve eaten enough breakfast before you get started because the process can knock the wind out of you.

1. Prepare your Scraper

If you’re using a metal scraper, it’s important that you prepare it for the job. The sharp lead edge can scrape your boat bottom and cause lots of scratches and gashes, going as far as damaging your gelcoat.

Before you get started, round off the corners of your scraper head and gently dull out the lead edge with sandpaper. This helps ensure that you won’t end up accidentally jabbing your hull with the sharp scraper head.

2. Apply Marine Growth Remover

This helps to soften the glue that holds the barnacles in place so you can use less effort to pry them off. Read the instructions on the product and apply accordingly. You might have to wait a few minutes to get the formulation to work its magic.

When time’s up, try and see whether you can pry off the barnacles with relative ease. For areas on your hull with significant or severe barnacle growth, feel free to add more product and wait a little longer for it to dissolve the barnacle’s hold.

3. Work from the Edges

Barnacles can be so frustrating to remove that some people will do anything and use maximum power to get them off. But that’s not recommended if you want to protect your boat’s hull. Instead, work at a shallow angle against the edges of the barnacles.

Attacking directly from above the barnacles or at a harsh angle could cause the tops of the barnacles to break off, leaving a thin layer of the growth stuck to the bottom of your boat. These can be a pain to remove, leaving you nowhere to get under with your scraper.

4. Brush with a Chainmail Brush

Now that you’ve gotten the barnacles off, you’re going to see a lot of marks where they once clung to your hull. At this point, you’re going to start using your chainmail brush to get rid of the residue.

You can also apply boat hull and bottom cleaner as you go. The chemical should help further soften those stains and make it easier for you to brush away the marks with your specialized brush. Don’t be afraid to apply the chemical generously especially if you’re working with more stubborn stains.

Removing Barnacles with a Pressure Washer

If your barnacle problem has been around for a while, then that old scraper might not be enough. This is when you’re going to want to pull out the big guns to get the job done. And we’re talking about your pressure washer.

The preliminary steps are all the same: apply marine growth remover and wait a while before you get to work. Similar to the scraper, you will want to attack the growth at a shallow angle. This prevents them from breaking off incompletely.

When you’re done, you can apply boat hull cleaner and brush away the marks and residue with your chainmail brush. Or you can apply cleaner and try to blast off the barnacle remnants with your pressure washer.

Whether you went with the scraper or the pressure washer method, it’s important that you apply anti-fouling paint to make the process of removing barnacles easier in the future (or to prevent it all together.) Sand down your hull to make it smooth, apply two coats or primer, and then slather on two to three coats of anti-fouling paint according to the manufacturer’s instructions.

Tips for Cleaning Barnacles from a Boat

Don’t make the cleaning job harder (or more hazardous) than it has to be. To keep yourself safe and to prevent further damage to your boat, keep these handy tips in mind:

Don't Let Barnacles Dry

Some boaters think that drying them up kills them and makes them easier to remove, but the opposite is true. Keep the boat moist for easier removal.

Wear Protective Gear

Barnacles will fly around as they’re released from your hull. And because they’re covered in all sorts of bacteria, you might want to protect your hands and eyes throughout the process.

Take your Time

A sloppy job might have you feeling more frustrated than when you started. Take things slow and don’t rush the process. With the right technique, those barnacles should peel right off.

Oh, Barnacles

Most boat owners are clueless as to how to remove barnacles from a boat and end up paying expensive fees to have it done for them. But you can actually get the job done with a few hardware store essentials and the right technique. Just make sure you protect your boat when your done so you can save it from potential barnacle invasion and skip the tedious clean up process in the future.

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