How to Under Skin a Pontoon Boat in an Afternoon

One of the reasons I like pontoon boats, more than some other boat types, is that you can modify them in more ways than one. The shape and the flat area of the deck are very customizable; you can almost do anything you want with it.

The same applies to under the deck area. Every other type of boat has a hull that you can’t touch aside from some minor improvements, but a pontoon boat will allow many different customizations. And among the most popular underdeck customizations is under skinning.

Under skinning of a pontoon boat is a process of attaching aluminum sheets to the bottom of the deck to reduce drag, water splashing, increase speed and make the boat ride more comfortable. The reduction of drag may decrease fuel consumption in many cases, depending on the water condition.

Another benefit of under skinning is the protection it will give to your boat. All the small branches and other debris that might have damaged your boat in the past will no longer be a problem. In other words, under skinning your pontoon boat is a must for any serious boat owner.

Now that you know the benefit and why you need to under skin your pontoon boat, let’s talk about how to underskin your boat. This article will walk you through everything you need to know to complete the job, even if you are doing it yourself.

How to Under Skin a Pontoon Boat

The process of under skinning a pontoon boat is pretty straightforward if you have the right equipment. The equipment you should have is as follows:

  • Marine-grade aluminum sheets
  • Jigsaw and 14 TPI jigsaw blades
  • Cordless drill
  • Aluminum rivets or coated stainless steel screws
  • Telescopic quick support rod (if you are installing it on your own)

Step 1. Buy 5052 Aluminum Sheets

The first thing you need to do is find a way to buy marine-grade aluminum sheets between 0.06 and 0.09″ inches thick. I suggest you go with 5052 aluminum because it holds well against corrosion. The other option is readily available 3003 aluminum, but I prefer 5052 because it’s tougher, even though it’s harder to find.

Measure the space between the pontoons and cut the aluminum just short of the length. You can use the jigsaw to cut the aluminum yourself or take it to a local shop. A simple job like that is pretty cheap, so if you don’t have the jigsaw available, it’s cheaper to have someone else cut it for you.

Tip: When cutting the aluminum sheets, make sure the pieces you cut overlap at the cross beam.

Step 2. Attach the Aluminum to Cross Beams

The most challenging part of the whole process is installing the aluminum sheets. To make your life easier, predrill the holes in the aluminum sheet edge every 6 inches or so apart before you do anything. After you are done drilling, use a telescopic quick support rod to lift and hold the sheets in place while bolting them with 1 1/4″ self-drilling screws to the cross beams. Don’t over-tighten the screws, though; you might damage the head.

The best way to install the sheets is to start at the stern and work your way forward toward the bow. This way, you can overlap the sheets if you chose to. Overlapping the sheets is unnecessary, but it is an option if you want to enclose the underdeck completely and reduce the drag just a little more.

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Step 3. Install Aluminum Side Pieces

Initially, many people skip this step but eventually end up doing it because it gives that extra support to the under skin aluminum and reduces the flow of water hitting the under deck.

What you will need are long pieces of aluminum, about 4 inches wide. Once you have those cut out, take them to a local shop to bend about an inch of the width at the 75-degree angle. Using a 75-degree angle is better than bending it at 90 degrees because it will snuggle against the under skin much more, and the fit will be tighter. This way, you will not have to bolt the side pieces at the top; you can only bolt them on the side.

Step 4. Apply Anti-Corrosion Coating

The last step is applying the anti-corrosion coating over all the bolts. This is the simplest part of the installation but one of the most important ones. At one point or another, metal will rust, no matter what anyone says, so adding a little extra protection won’t hurt. Properly applying anti-corrosion coating will extend the life of bolts and prevent the aluminum sheets from falling off while driving and potentially damaging the under the deck of your pontoon boat.


Under skinning your pontoon is the first thing you should do if your boat does not have it installed when you buy it. It is the best way to protect your boat, improve the ride and save some money by reducing drag and fuel consumption. And the investment is minimal. It should not cost you more than $500 to install an underskin if your boat is about 18′ in length. And even if you have a larger boat, the increase in cost is minimal, so there is no reason not to do it.

Even if you are not that handy, with the right tools that I presented above, it will not take you more than a few hours to do this. I’ll say, on a good day, the most amount of time spent on the installation of an underskin is about 4 hours. That is a small investment for the benefit that you will ultimately receive in return.

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