Your Guide To Barnacles On Ships (Problems & Fixes)

Barnacles are tiny marine creatures that can attach to your ship and ruin its paintwork. However, this is not the only damage these creatures can do to your boat. So, what can happen if you leave barnacles on ships?

A large colony of barnacles adds weight to your ship, slowing it down and prompting it to burn more fuel. These sea creatures can disturb the water flow over the propeller, thus affecting the ship’s movement. They can even ruin the ship’s paintwork, causing your ship’s hull to corrode.

Your Guide To Barnacles On Ships

5 Ways Barnacles On Ships Can Cause Problems

Barnacles are the common enemies of boat owners who keep their ships in the water for long periods of time. If you are using your boat in freshwater, there is only a slim chance that you will experience this problem as barnacles live primarily in salt and brackish water. However, while these marine creatures are not common in freshwater, you may see them in some instances. 

These sea creatures live by firmly attaching themselves to solid surfaces, so it makes sense that they see your ship as a good surface to stick on. Once barnacles attach to your boat hull, they secrete fat and a liquid that serves as glue, making it difficult to detach them. (source)

So, what kinds of problems can be caused by barnacles on ships?

1. Barnacles Increase a Boats Fuel Consumption

Your ship will become heavy once a colony of barnacles attaches itself. These creatures increase the drag on your boat hull, requiring the engine to use more power to maintain speed. And to use more energy, your boat will need to burn more fuel. 

Allowing a colony of barnacles to remain on a ship’s hull will mean spending more money on fuel.

2. Barnacles Reduce Ship’s Speed

Barnacles are rough, especially when a lot of them clamp together. They prevent the water from sliding over your ship’s hull smoothly, thus increasing the friction and resistance between the water and the boat. 

If your ship’s hull is smooth, there will be no resistance once you are in the water. So, your boat can run at the speed that you want. But when barnacles stick under the ship, they will increase drag and slow your boat down.

3. The Propeller’s Motion Can Be Affected By Barnacles

While barnacles on the hull affect the speed of your boat, they also can disrupt the flow of water over the ship’s propeller. This complex part of your ship is responsible for cutting through the water and setting the ship in motion. Once barnacles attach themselves to your propeller’s surface, they will create disturbances in the water flow over your propeller.

Once barnacles attach themselves to a propeller, the engine needs to work harder to run it. Such can damage the propeller’s bearings and shaft in the long run.

4. Barnacles Cause Damage To The Bottom Of The Ship

Barnacles themselves do not damage your ship’s hull directly. However, they will continue to grow if you leave them on the ship’s hull for a long time, which can damage the paint which protects the hull. 

Your ship’s paint protects it from corrosion. So, when barnacles have entirely damaged the paint, direct water exposure will damage the ship’s hull, causing it to rust. 

5. Barnacles Ruin Your Ship’s Appearance

The part of your ship that does not touch the water may look divine and can catch the eyes of your fellow boaters. But when they look below the bottom line, they might change their mind once they see the barnacles all over your boat. 

Of course, such will never be a problem for people who don’t keep their ships in the water. Unfortunately, however, it only takes a boat being left in the water for a few days before marine life begins to grow on the hull. (source)

How To Remove Barnacles On Ships (Light & Heavy Buildup)

It is best to get rid of barnacles on ships before letting an entire colony grow. If you wait until they infest your entire boat hull, you will need to spend hours on the removal work. You may even need to sand down and repaint the hull after removing the barnacles.

Let’s discuss some different ways to remove barnacles from boats depending on how light or heavy the buildup is.

How To Remove Barnacles On Ships

Removing Light Barnacle Buildup

The moment you see barnacle patches scattered around your ship’s hull, it’s time to get your scraper and get to business.

At this stage, you should avoid using a pressure washer when removing these sea creatures, as pressure washing runs the risk of damaging the paintwork of your ship. A pressure washer has a place in removing barnacles, but when the buildup is light, there are better and safer ways.

Instead, use a wooden spatula or plastic scraper. While these tools can still damage your ship’s paintwork if you’re not careful, they will do minor damage compared to using a pressure washer. 

Scrape The Barnacles Off

Place the scraper under the edge of the barnacles on ships so you can apply force when removing the entire barnacle cluster. Keep your scraper as parallel to the hull’s surface as possible. This way, you can avoid applying pressure on the ship itself.

After removing the barnacles, you will see the remaining circular calcium foundations called the husks. You can also use the scaper to remove them from the hull. However, you have to ensure that you are careful to avoid damaging the paint or gel coat of the ship. (source)

Use A Calcium Remover

There will likely be husks that you won’t be able to scrape off no matter how hard you try. In this case, you need a mild acid or a calcium remover to clean the hard-to-remove husks. Apply a generous amount of the chemical to the husk, allow it to penetrate, and then rinse with water. (source)

You can try using something like Barnacle Buster Concentrated Barnacle and Marine Growth Remover (Amazon) to dissolve the calcium buildup.

After several applications and gentle scrubbing, you will be able to remove the husks from the ship’s hull. 

Polish The Damage On The Ship’s Hull

Removing barnacles on ships can cause damage to the ship’s surface. If such happens when you are scraping barnacles off of your boat bull, all you need to do is apply a compound and perform some polishing. This way, you can restore the ship’s finish as if nothing happened.

3M Perfect-It Gelcoat Medium Cutting Compound + Wax (Amazon) is a good choice as it removes any oxidation and will fill in and cover up light to moderate scratches.

Clean The Ship’s Hull

Once there are no barnacles left on the ship’s hull, clean it using a boat wash and let it dry. Next, apply two or more coats of boat wax. This wax will slow down the barnacles from reattaching to your boat. It also makes it easier for you to remove new barnacles on ships. (source)

Removing Heavy Barnacle Buildup

Leaving your ship in the water for a long time will allow many barnacles to grow on the ship’s hull. In some cases, barnacles may cover a large area or even the entire hull. This buildup is difficult to remove and can damage the paintwork and the hull itself. 

Here’s how you remove a heavy barnacle buildup on ships:

Use A Pressure Washer

When there are many barnacles on your ship, you may find it difficult where to start or which edge you first need to scrape off. Scraping many barnacles off can also tire you out, especially if the barnacles cover the entire hull. You will need a pressure washer to remove the most significant possible number of barnacles. 

Your pressure washer needs to have a small nozzle and can release water pressure of at least 3000 PSI (pounds per square inch). (source)

Removing barnacles from a ship using a pressure washer.

When using a pressure washer, it’s important to position the spray parallel to the ship’s surface as much as possible. This way, you can remove the barnacles without cutting into the boat’s surface.

Scrape Off The Remaining Barnacles And Use A Calcium Remover On The Hull

Like what you need to do when removing a small barnacle buildup, scrape off the remaining barnacles that the pressure washer could not remove. Note: you may have to use a metal scraper when pulling a heavy buildup of barnacles on ships.

Then, apply a calcium remover on the husks a couple of times until you remove all of them. 

Wash The Hull Clean

After removing all the barnacles and husks, the next step is to wash the ship’s hull to see how much damage it has. If there are no scrapes or gouges on the ship’s surface, you may be able to fix it by applying a compound, polishing, and waxing. 

But if power washing and scraping are causing damage, you may need to fill it with resin, sand it down, and repaint it.

Apply Antifouling Bottom Paint

After repairing the damage on the hull, the next thing you need to do is apply at least two coats of antifouling bottom paint. If you want the color and effects to last longer, using more than two coats is ideal. The paint makes the ship look good, but it also makes it more difficult for barnacles to stick on your boat. (source)

Preventing Barnacles From Sticking On Your Ship (2 Ways)

Barnacles on marine ships are a huge problem, especially when you let them grow and invade the entire ship’s hull. They ruin the ship’s paintwork and surface, causing excess time and money for repairs.

So, before barnacles can damage your ship, there are several things that you can do to prevent them from attaching to your boat in the first place.

Clean The Ship’s Hull Regularly

Regularly cleaning the hull will allow you to remove barnacles that are just starting to attach to your ship. This way, you can prevent the barnacles from growing and becoming a colony.

But using a scraper to clean your ship or scrubbing the surface may scratch the ship’s exterior. Fortunately, you can prevent this from happening by:

  • carefully scrubbing the ship’s hull 
  • painting the hull with an antifouling paint mixed with epoxy resin and high percentile copper powder

Apply Antifouling Paint On The Ship

An antifouling paint contains the chemicals copper and biocide in it. Once you apply it to your ship, it releases copper, preventing barnacles and other sea creatures from sticking to the hull.

However, it is worth noting that antifouling paint can only prevent barnacles from sticking to your ship to some extent. While it can slow down barnacles from attaching to your ship’s hull, they will still grow in time if you are not cleaning your boat regularly. 

Additionally, you need to replace the antifouling paint every two to five years if you are keeping your ship in saltwater. (source)

4 Tips For Removing Barnacles On Ships

Removing barnacles is a difficult job. The process also inevitably damages the surface of your ship, so you also need to fix it after removing the barnacles. Fortunately, there are tips that you can follow to make the barnacle removal easier. 

Barnacles on bottom of boat: Tips to Remove Barnacles

1. Wear Protective Clothes When Removing Barnacles

When scraping barnacles off your ship, the first thing you need to do is protect yourself. Ensure that you wear a cut-proof pair of gloves as barnacle shells are sharp and can cut your skin open. 

In addition, these sea creatures have bacteria on them, which can affect wounds if you are not wearing gloves. It is also ideal for wearing a mask and eye protection to prevent tiny barnacle particles from getting in contact with your eyes, nose, or mouth. 

2. Keep The Barnacles Wet

The liquid glue that barnacles secrete adheres stronger when dry, making these sea creatures even more challenging to remove. For this reason, keep your ship in the water until you begin scraping the barnacles off. 

3. Do Not Scrape With Too Much Force

Scraping the barnacles is the process that can damage your ship’s hull. So, you need to be extra careful when doing this step. It is ideal to use a wooden or plastic scraper to reduce the chances of gouging your ship’s paintwork. 

4. Coat The Ship’s Hull With Wax

Removing barnacles on ships is one thing. However, these marine creatures will invade your boat again. You will have no choice but to repeat the removal and cleaning process. Fortunately, you can apply wax to your ship’s hull to make the barnacle removable easier. 

The wax serves as a protective layer to your ship, so it is easier to remove the liquid glue and husk from the barnacles. (source)

Barnacles On Ships – Final Thoughts

Barnacles attach themselves to firm surfaces, such as rocks and your ship’s hull. They are difficult to remove and may even damage your boat. Barnacles on ships can:

  • Slow down your ship
  • Affect the efficiency of the propeller
  • Make the boat heavier, prompting its engines to burn more fuel
  • Damage the overall look of your ship

For this reason, it is ideal to remove barnacles from your ship’s hull before they build an entire colony.

You may also prevent barnacles from attaching to your ship by treating it with antifouling paint and wax. Prevention is crucial as barnacles can take a large amount of money and time to address if you leave them untreated.


  1. Yoseph Bar-Cohen. Advances in Manufacturing and Processing of Materials and Structures. CRC Press, 2018.  
  2. Tony Disanto. Boat Works. USA: Tate Publishing, 2010. . 
  3. Bernard Gladstone. “Boatkeeper.” MotorBoating. Vol. 176, No. 4. October 1995. 102.  
  4. Ernest A. Zadig, Joe Gribbins. “Help In A Boat’s Battle With Flora And Fauna.” MotorBoating. Vol. 138, No. 4. October 1976. 30.  
  5. National Association of Manufacturers (U.S.). American Industries, Volume 10. National Association of Manufacturers, 1909.  

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