How To: Repair a Pontoon Boat

We’re all familiar with one-man pontoon boats; those inflatable single person watercraft which range from small, pond-appropriate single-bladder floats on up to whitewater grade, three-man catarafts.

Most pontoon boats have an internal bladder made of a lighter grade of material than the multi-dernier PVC exterior we actually see.  On many boats, this is a polyurethane bladder, which can be easily patched. (Some boats have a PVC bladder which may require special glues; these instructions apply only to the more-common polyurethane models). Over time, creases in the bladder, sharp impacts, or sheer wear-and-tear can cause pinhole leaks, which prevent the pontoons from retaining air.  Oftentimes these leaks are most noticeable after a long day on the water or a period of storage.  They may develop when the boat is broken down for transport (a practice best to be avoided as much as possible).

Repairing these leaks is a hassle but certainly doable and worthwhile.  A boat that does not leak will require less fatiguing pumping and will ride better throughout the day.

We’ll be repairing this 2000-era J.W. Outfitters “Renegade” boat, a nine-foot craft similar to many other models on the market, such as those made by Water Skeeter or Scadden Boats.

You will need the following items:

(1) A squirt bottle
(2) Liquid Dish Soap
(3) Access to your pump
(4) A toluene-based vinyl glue, such as Aquaseal or a vinyl mattress repair kit glue
(5) Water
(6) Rubbing Alcohol
(7) A rag

(8) A permanent marker

Start by disassembling your pontoon boat if you have not already done so. 

When the boat is deflated, look carefully for the zipper access to the internal bladder.  On the J.W. Outfitters boats, this zipper is hidden by a flap on the rear of the pontoon.

Extract the tubes from the casing and stretch them out carefully.  Best to do this in a clean area free of sand, gravel or debris which might scratch or otherwise damage your bladder.

Attach your pump and inflate the pontoons.  You are going to over-inflate them by about 20%; when inflated inside the cases, the bladders are not actually fully charged.  You want them to be tight but not so taut that they make pinging noises when you touch them or make a pump stroke.

Once inflated, fill your squirt bottle with water and a generous dollop of liquid dish soap, then liberally spray the entire bladder. 

Look closely.  You will see bubbles growing from pinhole leaks, and may even hear the air squealing as it leaks out.  Soap causes the squeals to increase in volume, making them easier to find. The key is to watch for bubbles that grow; not those that merely formed when you sprayed the boat. Sometimes they will leave a trail (like in the photo below), which is easy to follow.

When you spot a leak, wipe off the soap with your rag and circle the area in permanent marker. (Don’t worry, this will be hidden when the bladders go back inside the cases).  Work slowly and cover the entire surface area of both pontoons. When you’ve found and circled all your problem areas, hose off the bladders so they do not remain soapy.

Deflate the bladders so that the leaks are no longer under tension. Then, pre-treat your circled areas by wiping the surface area with rubbing alcohol.

Finally, using your toluene glue, apply a generous, coin-sized (and coin-thickness) amount of glue over the pinhole leak.

Let the patch dry overnight or for a few hours, then tuck the bladders back into their cases by grabbing the inside of the tip of the case and holding it to the tip of the bladder while you stretch the case back to its full length. Lubricate with water if necessary. When you’ve tucked the bladders back in, take care to make sure both tips are filled by the bladder ends, then zip your cases up and re-inflate.  You’re done!

Repairs made this way last for years, but they will be strongest if you leave your boat inflated as much as possible.

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