How to Clean a Boat Hull

July 25, 2022

Cleaning a boat hull is a necessary task that often goes overlooked. Over time boats get dirty and weathered, so it’s important to regularly clean their hulls to remove any buildup of scale, rust, algae or salts.

In this article, find out from the experts at the National Boating Safety School how to clean and maintain a boat hull.

Boat hull cleaning has added value

The hull is the part of a boat most exposed to the various elements. Over time, this can become covered with dirt, scum and weathering. The gelcoat that covers the hull may also turn yellow from ultraviolet light.

It’s always a better idea to maintain the value of your boat’s hull. For this, it is essential to regularly clean the hull of your boat with the right products, and especially, the right methods.

Cleaning a boat hull explained

To ensure the longevity of your boat, it is recommended that you clean your boat hull several times a year depending on the frequency of use and the marine environment. A rinsing of the hull after each trip and a light annual polishing are also recommended.

7 tips on how to clean a boat hull

Although the marks may look impressive, it is important to keep in mind that boat hulls were designed to withstand a lot of damage. Therefore, a boat hull cleaner and clear water are more than enough for a complete cleaning when the boat is securely mounted out of the water. Below are some recommendations from our experts to thoroughly clean your boat’s hull without damaging it:

  1. Get a bucket of fresh water and use a low-powered water jet to rinse the entire hull Be sure to remove salt stains, mold and algae that have clung to the hull
  2. Buy a cleaner made for boat hulls and dilute the labeled amount in a bucket of water
  3. Scrub the hull down to the waterline with a large, soft sponge. Soak the sponge in the cleaning solution and wring it out lightly before you begin
  4. Be careful not to damage the paint and clean from top to bottom, and from bow to stern
  5. When finished, gently rinse the hull with a low-powered jet stream of water
  6. Run a second sponge soaked in clean water over the hull to wipe off any residual stains and cleaner
  7. Finally, avoid cleaning your boat’s hull in the sun, as the water and cleaner may dry quickly. If this is not possible, proceed in small areas

If you own a motorboat, we also invite you to read about how to clean a boat fuel tank.

How to clean yellow stains off a boat hull

After a few years of use, even the shiniest boat hulls can stain yellow. This can cause the gelcoat that covers the hull to discolour from ultraviolet light or become dull from oxidation.

To restore the shine to your hull and obtain the best possible result, it is necessary to prepare the surface to be treated beforehand. In order to remove all dirt and scum, we invite you to follow the tips described in the paragraph above “7 tips on how to clean a boat hull”.

Once the boat hull is clean, the yellow stain can be removed by using oxalic acid (sorrel salt) diluted in a bucket of clear water. It is recommended to put on protective glasses, gloves and clothing before handling this solution. Wipe the yellow stained areas with a cloth soaked in the solution and quickly rinse the area with a low-powered stream of water.

Learn more about boat hull maintenance with the National Boat Safety School

Overall, hull cleaning is an important part of keeping your boat performing at its best. By following the advice of our experts, you can maintain your boat’s hull thoroughly without worry.

If you’re interested in learning more about what it takes to maintain a vessel or obtain a boating license, the National Safe Boating Institute is your best bet.

Enjoy our Transport Canada approved boat safety course and be ready to take the boating exam to legally navigate Canadian waters.

Get your card today