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How to Repair Aluminum Boat? (Holes, Tears, Corrosion, and Electrolysis)

Fact checked by William Hart

how to repair aluminum boat

Found a leak in your aluminum boat? Don’t call for boat servicing yet! Aluminum has a low molecular density, which makes it pliable and easy to repair. With a few tools and a thorough guide, you can fix it by yourself.

In this article, we will show you how to repair aluminum boat when there are holes, tears, corrosion, and electrolysis. Don’t let a leak ruin your fun on the water. Quickly gather what you need and get to work!

Table of Contents

How to Repair Holes and Tears on an Aluminum Boat


What you need

An aluminum boat hull repair requires:

  • Boat soap
  • Aluminum boat patch kit (or marine sealer, a mixing pot, and a mixing stick)
  • Sandpaper

Step 1. Find the leaks


Before you proceed to repair holes in the aluminum boat, always try to identify all the leaks. You don’t want to patch a hole just to find another one the next day. You should:

  • Load your boat on its trailer
  • Close the drain plug
  • Use a garden hose to fill the boat with water

Now, inspect the hull and the bottom. Larger holes are easy to spot while small ones are not. So, wait at least an hour before removing the drain plug.

The most common leakage spots are the rivets, livewell drain, drain plug, transducer screw holes, and transom.

Step 2. Clean the areas around the holes


When you find the leaks, clean the areas before repairing them.

  • Mix boat soap with water to make a cleaning solution
  • Soak a sponge in the solution and clean up any dirt and debris
  • Rinse with water

If the aluminum is uneven, hammer it down. Aluminum boat patching is more efficient on a clean and even surface.

Step 3. Apply epoxy


Follow the instructions of your patch kit to mix the epoxy. Then, apply it to the hole with a paintbrush. You should cover it as seamlessly as possible. Wait at least an hour for the epoxy to dry.

Check our list of top-rate marine epoxy for different types of boats here!

Step 4. Sand down the repaired area

To cover the damage, blend the epoxy into the aluminum by sanding down the patched area. If necessary, you can paint it the same color as your boat.

Note that marine epoxy might not be enough to fix large holes and tears. In some cases, you must use a welding torch to mend them.

Check out this video for the procedure:

How to Fix Aluminum Corrosion


What you need

  • Boat soap
  • Sandpaper
  • Heavy-duty corrosion inhibitor
  • Pressure washer

Step 1. Clean the areas

To fix corrosion, you must clean up all the dirt and debris on the surface. Remember to put on protective gloves.

  • Blast away the debris with a pressure washer
  • Make a solution of boat soap and water
  • Dip a brush in the solution and scrub the surface
  • Rinse with water

Step 2. Sand down the corrosion

Next, remove the corrosion with sandpaper. You should begin with coarse-grit sandpaper and then move on to fine-grit one.

If you have a rotary buffer, use it to buff the surface after sanding. Go over the areas several times to get rid of all debris. After that, wipe them off with a rag.

Step 3. Use the corrosion inhibitor

Finally, spray a generous amount of corrosion inhibitor on the repaired areas. It will protect the surface from corroding in the future.

Most corrosion issues happen on the gunnel. To maintain the results of your aluminum boat gunnel repair, you can add a polyester gunnel guard.

How to Fix Electrolysis


Electrolysis corrosion happens when an electrical current runs through two dissimilar metals in an electrolyte, such as salt water.

Let’s say you have an aluminum boat, but its propeller is made of zinc. When an electrical current flows through your boat, it strips electrons from the zinc and deposits them into the aluminum.

Over time, this process causes severe corrosion. If you treat electrolysis similar to regular corrosion, the problem will return. Note that electrolysis happens in salt water, so only treat aluminum corrosion under the waterline with this procedure.

What you need

  • Sacrificial anode
  • Heavy-duty corrosion inhibitor
  • Boat soap
  • Sandpaper

Step 1. Install the sacrificial anode

Electrolysis is almost unavoidable on aluminum boats, but an anode will sacrifice itself to the process. It gives up its electrons and weakens over time to protect other parts of your boat.

So, inspect the anode on your aluminum vessel. It is often located on the trim tabs or shafts. If your anode is in bad condition, replace it. If your boat doesn’t have an anode, install one.

Step 2. Check your wiring

Electrolysis only occurs when there is an electrical current. Do you have a stray current on your boat?

Currents that are low-voltage and cause no harm to live things can also cause electrolysis. It can be a frayed wire from your lighting system or a loose wire from the battery touching the hull.

If your anode dies too quickly, the issue may be from your dock. It might have a faulty ground lead that connects to your underwater bonding system. You should talk to other boaters to see if they have the same issue, then inform the maintenance team.

To fix electrolysis, you must find the root of the problem.

Step 3. Clean the corrosion

Now, proceed to clean the aluminum corrosion.

  • Wash off the corrosion with a pressure washer and boat soap
  • Sand down the surface
  • Spray corrosion inhibitor to protect the repaired areas

Don’t use the inhibitor on your anode or it will lose its function.

Tips: Use the right cleaner to get the best results.

Step 4. Maintain your anode

You should clean your anode regularly and keep it from grime and buildup so that it can do the job.

In addition, remember not to mix metals on your aluminum boat. Opt for aluminum fittings and components (e.g., fasteners, bolts, nuts) for your boat. If possible, switch to aluminum shafts and propellers.


When you notice holes and corrosion on your aluminum boat, quickly proceed to fix it. A minor issue can become irreparable in just a couple of weeks. Repairing aluminum boat hulls seems like a job for professionals, but with the right tools, you can handle it yourself.

If you find our article helpful, please share it with your friends. We believe every owner needs a good guide on how to repair aluminum boat.

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