How to fix a leak in aluminum boat

With the weather finally taking a turn for the better, our plans for outdoor activities can eventually come into full swing. Riding a bicycle or hiking up the mountain are the most popular choices, but nothing can quite compare to taking a boat out on a lake or the sea.

The past year has been quite hectic, with only a few having enough time to maintain their boat correctly. Whether marooned or left on the trailer, the small leaks and seepage might have worsened, and now is the right time to address them.

Fixing aluminum boat leaks seems like a job only a professional can handle, but with the right skill, mindset, and patience, you’ll be able to handle most of the problems all by yourself. This article will guide you through the process of finding a leak spot and the implementation of the different methods of mending it. 

Boat leaks can range from minor inconveniences to causes for panic and immediate intervention. However, finding the spot that needs addressing can be more of a challenge than repairs. Imagine the trouble of finding a puncture in a bicycle tire and then multiply it several times over. 

The method that seems to provide the best results is to have the boat on land and fill it up with water. Inspect the hull, and if the leak is large enough, you will spot it immediately. Otherwise, wait a few hours. If you are still having trouble spotting the leak, adding food coloring to the water will make it more visible. 

If you can’t find any leakage with this method, but your boat is still filling up, see if the drain plug seal is working well. Livewell pumps can be a source of your problems and are particularly hard to spot on the transom because it is hard to identify where the water is coming from. The best method of spotting a leak is to start with the easiest and cheapest causes and work your way towards the major faults.

The most common leakage spots are:

  • Rivets
  • Drain Plug
  • Livewell Overflow
  • Livewell Drain
  • Transducer Screw Holes
  • Transom

Once you have identified the trouble spots, it is time to address them with the right tools and materials. In the next section, we will cover tried and true ways of fixing aluminum boat leaks.

Replace The Broken Part

This point is pretty self-explanatory, but it is worth mentioning the importance of reliability on a boat. Cutting corners and compromising on the maintenance of a car might get you by. However, it can also get you stranded on the side of the road. With a boat, you don’t have such a luxury, so refrain from testing your luck. 

Seal The Leak

You can address small cracks and holes with a few relatively cheap products. You might need to do some sanding by hand to clear off any dirt that will prevent proper sealing. Make sure the surfaces are fully dry before applying any solutions.

Various products are specifically designed for this very purpose, from Flex Seals and Marine Adhesive Sealant to a multitude of different epoxy solutions. We have found that no particular solution stands out the most, therefore select the product available and easiest to use. Remember, you will need a heat gun with some epoxy solutions to melt it and force it through the gaps. 

Depending on the size of the boat, flipping it over might be more of a challenge than you would want, so read the guides to verify whether or not you can apply the sealant while the boat is trailered. Using a liner coating for a pickup truck’s bed on the inside of the boat is an inexpensive way of adding more protection.

Re-Rivet The Boat

Re-riveting the entire boat can be so expensive and time-consuming that it brings up the question of whether or not it is easier to buy another boat. However, changing a few problematic rivets shouldn’t be a problem if you have some repairing experience. 

Order some closed-in rivets and rivet burrs online. Because they are closed, the rivets will not let the water through, while the burrs or washers are there to prevent the rivets from punching through. You will also need a rivet gun, a through-hull marine adhesive sealant, and a power drill. 

Drill into the center of the old rivet and punch it through with a screwdriver, one that is smaller than the diameter of the hole. Place the new rivet into the gun, and place the marine sealant around the rivet. On the inside of the boat, set the burr for reinforcement, and punch in the new rivet. Wipe off the excess sealant, and you are all finished!

Consult With A Professional 

Sometimes, the problem can be too challenging for you to handle. Fixing the issue yourself may be the cheapest option, but messing up can cost you much more than it would initially. There is no shame in consulting with a professional company, or at least an experienced friend. The most important thing is to properly fix the problem and avoid redoing it after a few months.

We have shown you that fixing an aluminum boat leak is not as complicated as you might have thought. The repair can take a few hours at most, so have the patience to let the boat dry for a few days, and you’re set for the foreseeable future.

A common problem affecting aluminum boats are leaks. Collisions with underwater obstructions, beaching boats, and years of pounding waves are the likely causes of loose or missing rivets, widening of seams, and hairline cracks and tears.

Tip: Shop boat supplies such as: cleaning supplies, boat carpet, battery chargers and more at Bass Pro Shops.

Generally regarded as simply a nuisance, the hard facts are that a leaky boat left unfixed can quickly become a sinking ship. Although major damage should be left to the professionals, those minor in stature can easily be fixed with a bit of DIY.

Locating the Leaks in Your Boat

Ascertaining where water seeps in can be a tough chore. Problematic areas are often not noticed with a visual inspection, meaning a water test is your best bet.

Keep your boat level and hooked up to your tow vehicle for this step. With a garden hose, fill the boat with an inch or two of water, paying careful attention to the aluminum underside for any drips or leaks. Once found, use a waterproof marker to highlight areas that need attention. If none noticed, continue with the filling process.

Prepping the Boat

Once leaks are located and marked, pull the drain plug and raise the bow. To ensure best results, leave the boat in this position for two days in order to completely dry.

Use a stiff wire brush to lightly rough up the surface of areas that need repairing. This step will allow the bonding agents to better adhere to the aluminum, especially if the original area is shiny and smooth. 

Tools for Fixing Leaky Boats

How to fix a leak in aluminum boat
J-B Weld Clear Silicone All-Purpose RTV Sealant and Adhesive

Two products that work well for leaky boats are Epoxy Putty Sticks and Marine Adhesive Sealant. The latter is best used for filling in joint seams that have lifted or when sealing transducer holes. Epoxy is an excellent product for rivets, small cracks, or holes.

Following the product directions is crucial for best results. Epoxy requires hand kneading for one minute in order for the two compounds to mix. It then must be forced and flattened on to the aluminum within two minutes. The work time allowed is quite short, so knowing where you are applying it and how should be figured out in advance. Once cured, a permanent steel hard shell is left.

When repairing rivets, cover the entire area including a half-inch overlap. The same goes for cracks or holes. When filling seams with sealant, ensure a generous amount is squeezed into the opening, and after, run a finger or cloth along the edge to clean up excess and finish off.

Allow sufficient time for either compound to cure before getting wet.

Boat Safety Concerns

Safety glasses should always be worn when working underneath a boat. You don't want any of these compounds in your eyes. Wearing latex gloves to knead and apply each product is also recommended. The Epoxy in particular takes a vigorous scrubbing to clean off bare hands.

A leaky boat can become a thing of the past with just a few simple steps. Follow them this season and save yourself from going down with the ship.