Will a Pontoon Boat Sink? (Explained and Quick Facts)

Will a Pontoon Boat Sink

Pontoon boats are lightweight leisure vessels normally used for fishing, water sports and partying. Their lightweight design of a deck mounted onto two to three sealed aluminum tubes allows them to float with ease and makes for a versatile and stable boat. Used correctly, pontoons can be a very safe way to enjoy all kinds of water activities. However, push a pontoon boat beyond the limit they were designed for and you will run into the kind of trouble most boats face.

Will a Pontoon boat sink? Yes, Pontoon boats are capable of sinking, though fortunately, it is very rare. Pontoon boats are sometimes deemed ‘unsinkable’ because of their buoyant design – if one pontoon tube was punctured or filled with water, for example, the remaining tubes would keep the pontoon afloat. This buoyancy makes it incredibly unlikely for a pontoon to fully submerge. It is far more likely for pontoon boats to flip over than sink (and even then, this is mainly due to extreme weather conditions).

Many factors can determine whether a pontoon boat will sink or not and not all of them will necessarily be obvious. If you are new to using pontoon boats or simply wish to brush up on your safety know-how, read through this brief guide on reasons why pontoons may sink and tips on how to make your pontoon as sea-worthy as possible.

Can Pontoon Boats Sink?

With improper handling, poor maintenance, and severe weather conditions, Pontoon boats can sink, but these are extremely rare occurrences. The aluminum tube hull design of pontoons make them incredibly buoyant and resilient (even in the case of an extreme downpour), but rough, choppy waters and human error will make them likely to sink (more on these causes below).

How Low Should Your Pontoon Sit in the Water?

How low your pontoon sits in the water depends on the size of the ‘logs’ (the tubes that make up each side of the boat). Most of the time, pontoon logs sit fairly low in the water, but a good rule of thumb to ensure your pontoon is sitting correctly is for at least half (or less) of the logs to be under the water. So for example, a 30 inch log should have around 15 inches sitting in the water with 15 inches visible.

What Causes a Pontoon Boat to Sink?


All pontoon boats have a weight capacity as set by the manufacturer and a good way to check if you’ve exceeded the capacity is to look at the water line against your pontoons. If the water line is above the middle of the pontoon tubes, then you are overloaded.

Because of a pontoon boat’s incredible buoyancy, they can appear perfectly fine, even when over the weight capacity – it’s only when you start the engine and attempt to move that sinking will likely occur.

Poor Weight Distribution

You may have the correct amount of people on board for your pontoon size, but having them all gather on one end of the boat (along with any furniture and other accessories you have on deck) will soon risk tipping things over!

A pontoon should always be lighter in the bow area than in the stern – too much weight on the bow will force the pontoons lower into the water and cause the boat to ‘plow’ and take on water.

Water in the Tubes

Overtime, it’s common for small amounts of water to collect in the hollow aluminum tubing and thankfully, pontoons are fitted with drain plugs to allow you to pour excess water out. This isn’t so straightforward with newer pontoon designs though, since these tubes can be ‘chambered’ (meaning each tube is sectioned off into separate chambers).

In this case, some but not all of the water can be drained out. The best way to prepare yourself for this scenario is to carry out regular checks on your tubes and contact your pontoon’s manufacturer for guidance on draining the chambers.

Using Incorrect Motors

Each pontoon boat will have a minimum and maximum power level, so if you are using an inappropriate motor HP (horsepower), then this will affect how the pontoon operates. Using a lower motor HP than stated, for example, will not be able to lift the boat out of the water sufficiently enough, causing the plowing effect as mentioned earlier.

Reasons a Pontoon Boat Could Nosedive

Pontoons have a terrifying tendency to nosedive if used improperly and this can be due to a number of factors:

  • Poor weight distribution – in terms of both passengers and cargo, your pontoon should not exceed weight capacity on any side of the boat and cause it to become front-heavy and force the pontoons below the water line.
  • Improper power – too much or too little HP in your engine will mean that the boat can’t plane above the water or else, it has too much power that the sheer power behind the thrust can send the nose of the pontoon crashing into the water first, so stick to the power levels suggested by the manufacturer.   
  • Riding the waves – pontoons can handle being on waves to a certain degree, but attempting to ride through choppy waters at speed will quickly end up in a nosedive. They are essentially giant rafts, so attempting to imitate a speedboat will only cause you to take on water, not ride it out in impressive fashion!

Are Pontoons Safe in Choppy Water?

Because they have two hulls or ‘tubes’, pontoons can handle rough waters a little better than other recreational boat designs as they have greater stability than fiberglass boats with single-hull designs. While their design gives pontoons a good chance in choppy waters, there are still plenty of circumstances that can make this a dangerous venture.

There’s always the chance a large wave could capsize your pontoon or that your pontoon has poor steering, making it much harder to ride any incoming waves at an angle that keeps your bow up high. Safely sailing your pontoon in rough waters will depend on your weight load, your engine and ultimately how well you maintain your boat to make the ocean rides as smooth as you can.

How Long Do Pontoon Boats Last for?

Brand new pontoon boats can last between 10 and 20 years with proper care and maintenance before any major repairs need doing. The lifespan of each pontoon will vary based on the brand, previous use and whether you take it out in saltwater or freshwater etc. The aluminum tube design makes pontoons very durable and reliable, but if you’d like to help increase its lifespan, there are a few measures you can take to make your boat more efficient.

Making modifications such as ‘under-skinning’ (adding an aluminum sheet to the underside of your pontoon) will help to reduce drag and debris damage. Power-assisted steering will also improve handling on tricky maneuvers, helping to prevent dents and damage from rocks when beaching your boat.

How to Make Sure Your Pontoon Boat is Safe?

Pontoons weren’t exactly designed for long-term ocean sailing, but for times when you do wish to venture beyond the lakes and rivers, you’ll want to be sure your pontoon boat is safe and ocean-ready. As well as adhering to the above advice concerning maintenance and general good sense, here are some extra tips to keep your pontoon safe and sea-worthy:

  • Consider using thicker tube material (aluminum sheets 0.9 inches and thicker are best for ocean travel).
  • Don’t go ocean sailing with an engine that has less than 150HP.
  • Coat your aluminum in anti-fouling paint to slow corrosion from saltwater.
  • Tubes that are at least 25 inches in diameter are recommended for rough waters.
  • Add positive angle lifting strikes – these are devices that improve your boat’s lift and handling in choppy seas.
  • Keep your engine trim – when approaching waves, trim your engine’s thrust (use your hydraulic motor to tilt it to a higher angle) and this will keep the nose clear and out of the water.

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