Removing Limescale and Yellowing from Your Boat

Every boat owner knows the problem: after a season of boating, discolouration and stains appear on the hull, often just above and below the waterline. This stubborn fouling is commonly known as the “yellow waterline stain”. Fortunately, this problem can be easily solved with the right cleaning products. Here’s how you can do it.

What is yellow waterline staining? 

Yellow waterline stain is a yellowish or brownish deposit that forms along the waterline of your boat. This staining is caused by several factors:

• Limescale from the water that adheres to the polyester or gelcoat.
• Contaminants from the surface water, such as algae, mud particles and organic material.
• Rust particles and air pollution that mix with limescale and dirt.

If you frequently sail in stagnant or polluted water, the yellow waterline stain can quickly reappear. It is an eyesore: even if the rest of your boat is clean, it immediately looks neglected.

How to remove limescale and yellowing 

Luckily, you don’t have to scrub for hours to get your hull clean. With the right products, you can remove limescale and yellowing within minutes.

1. Dulon 22 Hull & Waterline Clean

Dulon 22 Hull & Waterline Clean is a powerful cleaner specially developed for cleaning the hull and waterline. It removes not only the yellow moustache but also limescale and superficial rust spots.

Benefits:

• Suitable for hull and waterline.
• Removes limescale, yellow staining and rust.
• No scrubbing required - the formula does the work.
• Also ideal for caravan or motorhomes.

How to use Dulon 22:

1. Apply Dulon 22 with a sponge or soft brush.
2. Allow the product to work for up to 10 minutes; do not let it dry.
3. Rinse thoroughly with clean water.
4. Repeat the treatment in case of heavy contamination.

2. Riwax Surface Clean

An alternative product is Riwax Surface Clean, a cleaner that effectively removes limescale, the yellow moustache, and other fouling. Apply the product, let it work briefly, and rinse off.

Tips to prevent new build-up

Here are a few tips to help prevent new build-up:

• Rinse your boat with clean (preferably fresh) water after use.
• After cleaning, apply a wax or coating, or periodically treat the surface with Premium Wash & Wax shampoo (Dulon 03). This creates a protective layer, making it harder for dirt and limescale to adhere.
• Regularly check the waterline and remove any build-up in time to prevent stubborn staining.

More information

At Polyestershoppen, you’ll find everything you need to keep your boat in excellent condition. Want to know more about cleaning or polishing your boat? Feel free to contact our product specialists, or explore our full range of Dulon and Riwax products!