Coating failures are among the most expensive defects in shipbuilding — and they are almost always preventable with proper inspection at each stage. Here is what coating QC looks like at the shipyard.
Coating protects the vessel's steel structure from corrosion for its entire service life. A coating failure discovered after delivery — delamination in a ballast tank, premature breakdown on the hull bottom — is extremely expensive to repair and often leads to warranty claims. The root cause is almost always a failure in surface preparation or application quality control during construction.
Effective coating inspection at the shipyard is not optional — it is one of the most critical quality control functions on a newbuilding project.
The inspection stages
- Surface preparation — verifying that the steel surface is blasted to the correct standard (typically Sa 2.5 per ISO 8501-1), checking surface profile, and confirming environmental conditions (temperature, humidity, dew point) are within specification before coating begins.
- Primer application — measuring dry film thickness (DFT) of the shop primer and checking for coverage defects.
- Intermediate and topcoat application — DFT measurements at multiple points per panel, visual inspection for runs, sags, holidays, and contamination.
- Holiday detection — low-voltage or high-voltage testing to find pinholes and coating discontinuities, particularly in ballast tanks and cargo tanks where coating integrity is critical.
- Stripe coating — verifying that stripe coats have been applied to edges, welds, and hard-to-reach areas where coating is most likely to fail.
- Final inspection — overall coating condition assessment before the tank or structure is closed up.
Documentation requirements
Every coating inspection must be documented with the date, location, environmental conditions, measured values (DFT readings, surface profile), the applicable specification, and the result (pass/fail). Photos are essential — particularly for pre-blast condition, surface profile comparisons, and any defects found. Classification societies and coating manufacturers may require specific documentation formats.
Tracking coating inspections digitally
ShipInspect Pro tracks coating inspections as part of the ITP workflow. Each coating stage — surface prep, application, DFT measurement, holiday detection — is a defined activity with its own inspection record, linked photos, and witness points where applicable. Coating status feeds into the project dashboard and monthly reports automatically.
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