Pontoon Tubes: What the Rebuilder Needs to Know
There are few old steel pontoons available to rebuilders. Steel tubes on new boats were discontinued about 1970. If you come across a set you must inspect them carefully. Condensation inside the tube usually makes them rust from the inside Steel tubes are often preserved by antifouling bottom paint. The outside may look fine. Test the strength of the tube, below the waterline, with a pointed object. If you find a good set, open the drain plug on top and pour a couple quarts of oil inside. Water floats on top of the oil and it protects the tube from corrosion.
The diameter of pontoon tubes has increased over the years. 1970/80’s pontoons were 19” or 21” diameter. 23” diameter were common in the 1990’s and modern pontoons can be as big as 27”, with 25” the most common. The rebuilder needs to pay attention to the size of the pontoons when buying a boat for rebuilding. If you are planning a small fishing pontoon or a boat that won’ carry much seating a 19” tube will generally be fine. If you want to rebuild a boat and put modern seating and even a sundeck or extended bow, you’ll want at least 21”, and maybe 23” diameter.
Rebuilders are usually better off finding a used pontoon and salvaging parts rather than buying pieces. You can find sets of pontoon tubes on e-bay for about $2500+. These are often new, scratch and dent pontoons, sold to a liquidator by the pontoon boat manufacturers. The reason they are salvage is often just something cosmetic, but it could be more. Try and get a warranty on the tubes against leaks.
You’ll need a transom, and locating a correct one may be harder than finding pontoons. The transom shown above was offered on e-bay for $1500 in March, 2018. You must have a transom to match the diameter of your pontoons. Then cross channels, deck trim, hardware, etc. all cost money. You can often find a used pontoon with a good chassis for under $2500. The cost of parts can add up quickly when buying individual components.
24’ 1990 chassis w/engine that needs work $1575
This is an air value used to pressure check for leaks. Riviera Cruiser had them on the back of the tube. They can be found elsewhere on other brands. People sometimes mistakenly believe that they should pressurize their old tubes. DON’T. Pumping air into old tubes may actually burst welds. New tubes were tested for leaks with low pressure.
Condensation can accumulate in pontoon tubes. It’s a good idea to pull the drain plug when buying an old boat for rebuilding, and again at winter storage time. We drain our boat every year and about a gallon of water pours out. Most people never drain them so don’t be surprised if a lot of water comes out the first time you drain it.
Tube repair. Spray shields can get bent or knocked off. There are weld shops in most lake areas that can do a repair. Replacing a spray shield or a leak should be a fairly inexpensive project. But labor to find a leak can add up. Local marine dealers might do the work or should be able to recommend someone.