Yellow Stain on the bow

Skipper May 9, 2006 Ask The Skipper

Roy Miser asked:

I have a yellow stain on the front of my hull where the water splashes up when underway. What do you recommend I use to remove this stain and after it is removed what can I put on the hull to keep the yellow from returning?

Answer:
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The infamous bow stain is usually found on displacement hull boats and is often referred to as “The (name of the body of water where you sail) frown, or smile, depending on whether you view it from the dock or the deck. The cause is from constant washing of surface pollutants in the water, against the hull, while the boat is underway. The most common pollutants that cause this stain are diesel, especially if there is commercial traffic in your area, and organic material such as algae or bacterial slime. There may be other causes such as industrial effluent or high mineral content such as iron that leaches out of the rocks or soil in the area.

Most of these stains can easily be removed from gelcoat with Waterline Stain Remover. Simply apply it with a paint roller (when the boat is out of the water) wait for 20 to 30 minutes and rinse clean. If the hull has been painted, use Algex. Spray it on and wait for 30 to 60 minutes, making sure that the surface remains wet so the chemical can work.

If this does not remove the stain, use Boat Scrub, full strength with a cloth and rub the stain out. In some cases where the stain has been on the boat for a long period of time and where it has been waxed over, it may be necessary to use a 50/50 solution of Boat Clean Plus and Boat Scrub. Use this solution with a soft cloth and rub the stain away. These methods will remove 98% of this type of stain without damage to gelcoat. If you use these products on a painted boat, be careful not to be too aggressive with the rubbing or you might scuff the finish.

If these products and methods do not work, you are looking at refinishing the surface with either gelcoat or paint.

It is almost impossible to prevent this type of staining, especially if it is caused by diesel or industrial pollutants or dyes in the water. A good way to reduce the staining and protect your boat is with VS721 Bottom Coat. It is extremely durable and resists attachment. If staining does occur, it will be the VS721 Bottom Coat that stains instead of your boat and will be much easier to clean. In these cases you will be using the VS721 Bottom Coat as a sacrificial material to protect your boat. Many boat owners have reported that the VS721 Bottom Coat has completely stopped the staining.

Thanks for your question,

Captain Aurora