Part of the reason you bought your pontoon boat was because you heard it was virtually unsinkable. Okay, you also like the length and size of the boat and just how relaxing riding in a pontoon is. Still, is your pontoon boat as unsinkable as you thought? Can pontoon boats sink?

Pontoon boats can indeed sink, although it doesn’t happen often. For your boat to go under, each pontoon tube would have to be severely punctured and damaged. Even then, your boat probably wouldn’t sink completely due to the airtight chambers of the pontoon tubes. These are designed to keep your boat upright.

You may be surprised by the news your boat can sink, especially if you’d assumed your pontoon was indestructible. If so, we implore you to keep reading. In this article, we’ll explain what it would take to sink a pontoon boat as well as provide tips on staying safe in the water.

Can Pontoon Boats Sink?

As we covered in the intro, yes, pontoon boats can certainly sink. You may have heard these vessels were unsinkable, but that’s just a misguided myth at best. No boat is truly unsinkable, including pontoon boats.

That said, it’s far more difficult to sink a pontoon than it is other boats. However, it can be done. You may have a friend of a friend who told you of someone they know whose pontoon boat sank. If you dig around online on pontoon forums and groups, you’ll surely come across a tale of boat sinking at some point.

If you’ve been riding your pontoon boat all this time thinking you’re impervious to sinking, it’s time to readjust your mindset. This way, you can be a safer boat driver.

What Causes Them to Sink?

Okay, now that we’ve established that pontoon boats can indeed sink, what does it take to down one of these babies?

It’s not easy, and it really is a combination of certain circumstances for a pontoon boat to go under. To understand what can sink a pontoon boat, we first have to talk about pontoon tubes in more depth.

Pontoon tubes provide buoyancy to your boat, so they’re incredibly important. With a pontoon boat, you have two tubes on either side of the boat. If your boat is a tritoon, then there are three pontoon tubes. The third one goes down the boat’s center.

While some pontoon tubes may be inflatable, many more are made of metal, such as steel or aluminum. Others may be built from nylon or PVC plastic.

There are chambers that segment each pontoon tube into individual sections. Each of these chambers is airtight. To make them even more durable, boat manufacturers will seal the pontoon tubes.

Both these measures are to keep your boat from sinking. The idea is that if part of your pontoon tube gets punctured or damaged, that’s only one chamber that’s broken. The others are still airtight and doing their thing. Even if one chamber is filled with water, the other chambers are supposed to be enough to keep your boat from sinking.

It would take severe damage to several chambers at once for the boat to begin sinking. Even then, both pontoon tubes would have to have been punctured or severely damaged to begin sinking. If the damage is limited to one side of the boat, then that side might begin to tip downwards, but it probably wouldn’t sink.

If you’re thinking your pontoon boat could ever be completely submerged in the water by damage to the pontoon tubes, it’s quite improbable but not impossible. All the tubes would have to be completely filled with water, which would take a while. Even still, the boat might not go completely under.

One thing that can help your pontoon fill with water faster is an open drain plug. Your pontoon boat may have a drain plug in the pontoon log. If so, then you must always tightly plug up the drain when you’re riding in the water. Otherwise, the log will fill up. While that alone won’t sink your boat, combined with damage to the pontoon tubes, you’re at a higher risk of sinking.

Is Sinking the Same as Capsizing?

Thus far in this article, we’ve talked about your boat sinking. This would be when the pontoon tubes and/or drain plug fill with water and your boat begins to fall into the water.

Is this the same thing as capsizing? Not exactly. Capsizing is when your boat tips over. Like sinking, capsizing is not something that happens often to pontoon boat owners. That doesn’t mean you should ever get lackadaisical about your pontoon boat driving and handling, though.

What causes a pontoon boat to capsize? If you ride in dangerous waters, such as choppy ocean waves, your boat could flip. All it takes is a large, cresting wave to lift your pontoon boat out of the water and turn it over.

Failing to properly distribute the weight onboard your pontoon boat is another major reason for capsizing. From passengers to equipment and cargo, everything must be evenly distributed. If the weight is shifted to one side more than the other, this puts your boat at risk of flipping.

While sinking and capsizing are two different issues, both are great to be aware of each time you take out your pontoon boat for a ride.

Tips to Keep Your Pontoon Boat Afloat on the Water

Are there any ways to prevent your pontoon boat from sinking? Indeed, there are. Let’s go over some tips and pointers for keeping your boat upright and in the water.

Close Your Drain Plug

We mentioned this a section or two back, but it’s worth talking about again. If your pontoon log has a drain plug, you want this to be completely closed. The stopper must be airtight. If it’s even a little bit loose, the force of the water you ride in can dislodge the stopper. This lets the water in your pontoon log.

While we said before that a full pontoon log won’t necessarily sink your boat, it does add extra weight. It could also increase drag, which is when your boat rides roughly through the water rather than gliding smoothly on it.

You might want to get into the habit of checking your drain plug before you disembark on a pontoon boat adventure. Push it in a little further even if it is closed just to make sure it won’t open.

Check Your Pontoon Tubes Before Every Ride

Your drain plug isn’t all you should check before you leave. You also want to inspect your pontoon tubes, both of them. While you can’t see what’s going on in the airtight chambers, you can look for visible exterior damage.

Scuffs and dings are normal if your pontoon boat is old enough. Instead, you’re searching for holes and punctures big or small. Anything that has pierced through the tough hide of your pontoon tubes could have damaged the pontoon chamber. That means water is probably in that chamber.

This isn’t necessarily a cause for concern yet, but it isn’t something you want to ignore, either. The problem could very well repeat itself in another part of the tube, leading to yet another chamber getting filled with water. Remember that the more damaged pontoon tube chambers you have, the higher the likelihood of your boat beginning to sink.

Many pontoon tubes have a sealing plate in each chamber. If you can remove the plate, you can empty the water in the chamber.

Know the Conditions You’re Riding in

Be smart about when and where you ride and know what you’re getting into before your boat leaves the dock. If there are jagged rocks beneath the lake you wanted to visit, you might want to reconsider. All it takes is one rock that’s higher up in the water and it can cause some serious wreckage to your pontoon tubes.

Also, while we’re at it, you should avoid taking your pontoon boat out in the ocean. No, this won’t put you at a higher risk of sinking. It does increase your chances of tipping or capsizing, though. Pontoon boats are simply not made for ocean riding.

Use High-Quality Line When Parked at a Dock

With smaller speedboats, there’s a chance that rough waters can push the boat beneath a dock. It can also flip the boat over, leaving its underside scraping against the dock and anything else nearby.

While this is not nearly as much of a risk with pontoon boats, you still want to use high-quality line when you park your boat anyway. The better the line quality, the lesser the chances of the line snapping. That means your boat will stay secure and free of damage that could lead to sinking.

Winterize Your Pontoon Boat Properly

Although you might not be thinking of winterization in the springtime, the cold season will be around again before you know it. To prepare, you want to make sure your pontoon log is completely empty. The same goes for the pontoon tube chambers.

If water is left in the pontoon log over the cold season, it will undoubtedly freeze. That can cause internal damage. Punctured chambers can easily fill with water, putting you at a higher risk of your pontoon boat sinking.


While pontoon boats can sink, it would take a lot for it to happen. Multiple pontoon tube chambers would have to have been punctured or severely damaged. Even then, part of the boat would probably sink, but not the whole thing.

That doesn’t give you the freedom to ever be lax on the water. Your pontoon boat is still at risk of capsizing or flipping over in rough conditions or through mishandling. By caring for your pontoon boat and being a conscientious driver, you can stay upright and prevent sinking.