Quick Answer
About 85% of coating failures on ships are caused by poor surface preparation, not the paint itself. If the steel surface is not clean, rough, and dry before painting, the coating will fail regardless of the product used. The fix is not better paint. It is better preparation.
The Most Common Reason Paint Fails Onboard
Most people assume coating failure is a product problem. It is not.
The paint industry has produced reliable, well-tested products for decades. The variable that determines whether a repair lasts 6 months or 5 years is almost always what happens before the paint goes on.
Three conditions must be met for a coating to bond and hold:
1. A clean surface, free of salt, oil, and grease
2. A rough surface profile, so the paint has something to grip
3. Sufficient dry film thickness, typically a minimum of 300 microns of primer
If any one of these three is missing, the coating will fail early. Not because the paint is bad. Because the foundation was not ready.
The Most Damaging Tool on Deck
The rotating wire brush is the single worst tool for surface preparation on ships, and one of the most commonly used.
Wire brushes do not remove corrosion. They polish the steel surface smooth while sealing contamination (salt, dirt, moisture) underneath. The result is a surface that looks clean but is not.
Paint applied over a polished, contaminated surface will typically fail within 6 to 12 months.
Better alternatives: abrasive discs, needle guns, sand blasting, or HP fresh water blasting above 750 bar.
Why Salt Is the Silent Destroyer
Salt contamination is one of the most overlooked causes of early coating failure.
Salt cannot be removed by mechanical cleaning alone. It must be washed off with fresh water before any surface preparation begins, and again before painting.
If salt remains under a new coat of paint, moisture will be drawn through the coating toward the salt deposits, accelerating corrosion from below.
Cleaning sequence that works every time:
– Wash with detergent and fresh water first
– Mechanical preparation second
– Fresh water rinse again before painting
What Structured Maintenance Changes
Vessels running without a structured corrosion maintenance system tend to repaint the same areas every 6 to 12 months. The work looks right at the time. But the preparation was not right, so the coating fails again on the same schedule.
A structured approach, with trained permanent crew, documented procedures, and consistent quality standards, shifts repair lifetime from months to years.
BSO Svendborg has documented 25–40% reductions in paint OPEX across 320+ vessels by addressing surface preparation as the primary variable.
Frequently Asked Questions
What is the most common cause of coating failure on ships?
Poor surface preparation. Approximately 85% of coating failures are caused by surfaces that were not sufficiently clean, rough, or dry before painting.
Does better paint prevent coating failure?
Rarely. The paint product is seldom the cause of failure. Surface preparation quality, cleanliness, surface profile, and primer thickness, is the determining factor in how long a coating repair lasts.
How long should a corrosion repair last on a ship?
A repair done to the correct standard, clean, rough surface with 300+ microns of primer DFT, should last 3–5 years in normal operating conditions. Repairs done with poor surface preparation typically fail within 6–12 months.
Why should you not use a rotating wire brush for ship maintenance?
Wire brushes polish steel smooth rather than creating a rough surface profile. They also seal contamination under the surface. Paint applied over a wire-brushed surface does not bond properly and fails early.