Are Pontoon Boats Filled with Foam? (Tube Types and Facts)

Are Pontoon Boats Filled with Foam

Pontoon boats are lightweight recreational vessels and as such, they need the aid of sturdy yet buoyant tubes or pontoons beneath the deck to remain afloat. Some pontoon boats are constructed differently to lower production costs, improve safety or ensure they are easier to repair. Depending on your needs (water sports, cruising or fishing etc.) it’s good to know which pontoon tube type would be best for you.

Some types of pontoon boats are designed with foam-filled tubes to provide maximum buoyancy and keep the tubes higher in the water to prevent drag. However, the majority of pontoon tubes are hollow and filled with air to achieve the same effect with a lower-maintenance design.

The idea behind foam-filled tubes is so that water isn’t able to enter, but if the tubes are badly damaged in an accident, water could still leak through and saturate the foam, requiring costly repairs and foam replacement. For this reason, most modern pontoon tubes are hollow and have a chambered design to guard against leaks more efficiently.

Pontoon Tube Types

There are 3 main types of pontoon tube design that can offer certain advantages depending on how you intend to use your pontoon boat. Let’s look at each tube style below along with their pros and cons:

Single chamber baffled round pontoons

This tube type is cylindrical and when made with aluminum it holds particular strength since a cylinder is the strongest shape this metal can be formed into. The tube chamber has several baffles (obstructing panels) welded at regular intervals with a purposeful void at the bottom to displace water.


  • Strong sturdy shape, particularly with aluminum construction.
  • Large diameter tube designs can carry more weight, making this ideal for entertaining large groups.
  • Baffle design allows for equalized pressure throughout the chamber.
  • Rear drainage plug to empty accumulated water and condensation.


  • Higher likelihood of sinking in the event of an accident due to single chamber design.

U-shaped foam-filled pontoons

This is a less common feature of many modern pontoon boats due to its many disadvantages. Some older pontoon boats are designed with U-shaped logs which have their cavities filled with foam to prevent water from entering. The issue with this is that should water enter due to an accident, the entire pontoon will need re-filling with foam or replacing altogether.


  • U-shaped design and foam insulation is designed for greater buoyancy.
  • Large log design allows for greater weight capacity.


  • Foam insertion design means baffles can’t be used, meaning unequal pressure.
  • Narrow tube width causes boat to sit lower in the water due to additional foam weight.
  • Increased likelihood of hitting underwater obstacles and causing costly damage.
  • Welding repairs are difficult due to tube insulation and overheating risk.

Round individual chamber pontoons

This pontoon tube type is normally designed with a set of three pontoons or ‘tritoons’ and each pontoon chamber has full-length baffles welded in intervals along the interior to provide airtight compartments – this fantastic feature ensures that any water damage is located to the individual affected compartment to ensure a much safer pontoon ride in the event of an accident.


  • Outstanding safety due to individual compartment design.
  • Hollow tri-toon design makes repairs easier to carry out
  • Localized damage in event of an accident.


  • Fairly expensive pontoon boat due to its labor-intensive design
  • Small individual drain plugs can make water drainage a slow process.

How Much Does It Cost to Fill Pontoons with Foam?

The cost to fill your boat’s pontoons with foam can vary from company to company, but boat enthusiasts on a forum for duck hunters and fishing quote a price between $2,000 and $3,000 to outsource the job.

You can fill your pontoons with foam yourself using a 2-part urethane foam. A 2 lb foam is a good light density choice to ensure your pontoon tubes will not sit too low and heavy in the water. A 10 gallon kit will make 40 cubic feet of foam and cost around $600, so to find out how much foam filling you would need for each pontoon, you simply need to multiply the pontoon diameter by its length i.e. 28 inch Diameter X 15 inch Length = 68 cubic feet.

What is a Pontoon Tube Diameter?

On average, most current pontoon boats feature pontoon tubes with a diameter of 25 inches or above at an optional extra cost. Mid-size pontoon boats (around 20 ft and longer) are typically offered with this diameter range.

Older pontoon boat models meanwhile tend to have smaller tube sizes of 23 inches and below – these tend to sit lower in the water and lead to more drag which makes them more difficult to maneuver in rough waters and guzzles up more fuel. Always try to aim for 25 inch diameter tubes and above for a more efficient pontoon.

How Much Does a Pontoon Tube Weigh?

Pontoon tube weight can vary depending on the material the tubes are made from (fiberglass, steel, aluminum etc.) and whether they are hollow or foam-filled. But assuming that the pontoons are constructed from aluminum, as the majority of modern pontoons are, a typical 24-25 inch diameter tube may weigh between 150 and 200 lbs individually.

Weight will vary based on whether the tubes contain baffles or partitions within the chamber, the style of the brackets attached to the decking, and external features such as splash fins etc.

Can a Pontoon Tube Be Repaired?

Yes, most modern pontoon tubes can be repaired if the damage is detected early. To repair a crack in an aluminum pontoon tube, the most effective method is to weld the damaged area and reseal it to prevent further leaks – this provides a sturdy barrier for large-scale cracks, but for smaller holes, many boat owners recommend using a compound steel putty for a quick emergency seal.

Steel putty, which can be found in most hardware or marine specialist stores, hardens quickly once applied to small cracks and holes and delivers steel-like strength that holds up well in water, making it perfect for sealing up leaks as soon as you spot them before you have a chance to weld on land.

Both aluminum and fiberglass pontoon tubes can be repaired with an epoxy solution which creates a similarly tough, hardened barrier against leaks.

Older foam-filled pontoon tube models can still be repaired though these can often be expensive compared to modern hollow tube designs, since the inner foam insulation is instantly compromised once it meets a water leak.

Are Pontoon Tubes Pressurized?

Some pontoon tubes are pressurized and filled with either air or nitrogen whilst others operate on a flotation system of water displacement. Single chamber baffled pontoon tubes, for example, are built with v-shaped hulls to cut through the water whilst pressurized pontoon chambers strengthen the inner walls of pontoon tubes to improve efficiency and decrease water damage.

Newbie pontoon boat owners often assume that adding more air pressure to their pontoon tubes will increase buoyancy and efficiency but this can often do more damage than good, so be sure to check the precise PSI reading (Pounds per Square inch) for your specific boat’s tubes and seek technical advice.

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