How do you Fix a Leaking Pontoon Boat? [SOLVED]

You are enjoying your pontoon trip. Suddenly, you notice that there is a leak in your pontoon boat. Leaks are one of the quickest killers of a good time.

Through this article, we will guide you on how do you fix a leaking pontoon boat.

You can fix a leaking pontoon boat using a self-hardening plastic metal called putty or by using Flex Seal Liquid. But, identifying the leaks at the right time is the most important thing as unidentified leaks, over a long time, can cause harm to the performance of your pontoon boat.

Before discussing how to fix the leaks of your pontoon, let’s discuss why the leaks occur.

Table Of Contents

Reason Behind Leaks

The pontoon boat’s exterior is sturdy but not thick enough, making them prone to damage. 

Pontoon boats are designed for leisure and not for heavy-duty use. In case of any collision or if they collide too hard, they become prone to damage.

Another reason for leaks can be damaged tubes. The outer layer of pontoon tubes is composed of either aluminum or steel and encases a float of PVC, foam, or plastic. So if any one of the tubes gets damaged, it can cause a leak and fill the boat with water.

Identify the Leaks

You can quickly and effectively repair the leaks if you identify the place and spot of the leakage. 

You can find out the place of leakage by the following mentioned ways:

  • If the water goes inside the pontoon due to leakage, you can identify where the leakage is.
  • You can fill your pontoon boat with water with the help of a drain plug and can identify where the leak is.
  • Or with the help of an air compressor, you can fill up your pontoon with air. When you deflate your pontoon the hissing sound will indicate the place of leakage.

Things Required for Fixing the Leak

  1. Self-hardening plastic metal, called putty
  2. Acetone
  3. Sandpaper
  4. Epoxy waterproof sealer
  5. Paint brushes
  6. Non-foam rollers
  7. No-sand fiberglass primer
  8. Dust mask

How do you Fix a Leaking Pontoon Boat?

To fix and repair the leaks, you can follow these simple steps.

  1. Identify the place of the leak. It will help you to repair the leak effectively.
  2. Relocate your pontoon to a dry location. Don’t do the repair work while the pontoon boat is still in the water.
  3. With the help of a rag, clean the surface around the leak. It would help during the repair process.
  4. Buy aluminum putty or self-hardening plastic metal for repairing the leak from your nearest hardware store.
  5. Now with the help of sandpaper, sand the area around the leakage spot to provide the repairing compounds a good surface to stick on.
  6. With the putty, fill the small punctures according to its directions. If the area has pinholes, mix Epoxy waterproof sealer with the putty with a rollable consistency.
  7. After allowing the putty to cure, sand it to make it smooth.
  8. With a coat of no-sand primer, cover the area where putty has been applied and allow it to dry.
  9. Now paint the area with no-sand fiberglass primer using disposable paint brushes.
  10. Apply a coat of metal polish to the boat’s surface.
  11. Let the coat get dried completely before putting your pontoon boat back into the waters.

And voila! Your leaking pontoon is repaired, and your pontoon is now ready to go back into the waters.

Flex Seal Liquid

Another method or tool that you can use for fixing a leak in your pontoon boat is by using Flex Seal Liquid.

What is Flex Seal Liquid?

Flex Seal Liquid is basically liquid rubber. It is a thick liquid that seeps into cracks and holes. On drying, it forms a watertight, flexible, and rubberized coating.


Here are some precautions that you should take while applying Flex Seal Liquid:

  1. Clean up the area where the seal is to be applied.
  2. Wear protective clothing.
  3. Make sure to check the weather forecast to ensure that it doesn’t rain for about 24 hours after application.
  4. Apply one coat at a time. Each paint coat should get dried before moving on to the next one.
  5. Test the flex seal liquid in a small area first, as every leak is different.

Why Flex Seal Liquid?

Flex Seal Liquid makes an excellent option for fixing pontoon leaks as it bonds well with aluminum. 

Aluminum can corrode due to many reasons and can lead to pinholes. Through the pin holes, water might get filled inside your pontoon and affect the buoyancy of your pontoon boat.

After identifying the pinholes or leaks, apply Flex Seal liquid over them and seal the leaks.

Does Flex Seal Stick to Aluminum?

Flex Seal Liquid is a very versatile piece of equipment. It gels with almost every surface ranging from aluminum, rubber, wood, concrete, glass, etc. 

Also, it prevents corrosion and is suitable in both summers and winters. It neither will melt and drip in summer nor gets cracked or peeled during the winter.

Also Read: What type of gas does a pontoon boat use?

Pontoon Tubes

Earlier in the article, we discussed that leak in the pontoon boat can be caused due to damage to the pontoon tubes.

Now let us discuss what is inside these pontoon tubes.

Inside the Tubes

The pontoon tubes are foam-filled tubes that are mostly hollow. To check the leaks and to strengthen the inner walls of the tubes many pontoons nowadays are filled with air.

Now in the modern versions of pontoon boats, pontoon tubes are being chambered and divided into different sections.

Why are tubes filled with air?

The pontoon tubes are filled with air because of two reasons:

  1. To prevent tubes from causing leaks.
  2. To strengthen the inner walls of the tube.

For many pontoon owners, the reason behind getting their pontoon tubes filled with air is to strengthen the inner walls of the tubes.

But the main reason for the tubes to be air-filled is to prevent and check for leaks. Manufacturers do this because if the air escapes from the tube, it means that water will enter through it when the pontoon is afloat. So it acts as a good way of identifying a leak.


For a pontoon owner, a leak is the biggest way to ruin a beautiful day. Make sure that you regularly maintain and check your pontoon boat for any leaks. If the leaks are unattended and not repaired for a long time, it can affect the buoyancy and performance of your pontoon boat.

Follow the tips mentioned in the article to fix leaks and pinholes in your pontoon boat and enjoy your pontoon trip with your friends and family without any hassles and worries.

After fixing the leaks and pinholes, drive your pontoon with your peers and enjoy your time by the sea.

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