Shining Despite Challenges: Secrets for Impeccable Coating in Grey Water Tanks.

Grey water tanks in yachts face a tough environment with fluctuating temperatures and a mix of chemicals, making coating integrity crucial. In Optimiza during the last years we´ve identified several issues in the vapor phase area where the coating is prone to premature failure. Trough on-site inspection and laboratory analyses, we´ve found numerous cases of significant coating deterioration and severe corrosion in this area, due to factors like chemical exposure, temperature variations, condensation, poor chemical resistance, and inadequate surface preparation and or paint application.


This breakdown compromises the coating´s chemical resistance and adhesion, leading to blistering, delamination, and severe pitting corrosion. Surprisingly, the coating in the immersed areas doesn´t show the same failure pattern due to different exposure conditions. Conducting a thorough failure analysis by an independent lab is essential, involving a condition survey, sample collection, proper analytical research, and fluid testing.


To prevent standard coating system failures in the vapor phase area, considering alternative coatings designed for tank specific conditions per type of yacht is crucial. Yachts grey water tanks vary in chemicals and exposures, impacting tank size and volume which will affect to fluid concentrations and differential of temperatures.


Preventive measures may involve the selection of coatings with enhanced chemical resistance, improved adhesion and better tolerance to temperature and humidity variations. Accelerated laboratory tests under ISO or ASTM standards with appropriate selection of fluid simulation and test programs, provide valuable data for comparative studies in a short period of time (<30 days). Correct surface preparation and specific application techniques, followed by a robust inspection test plan, are crucial to ensuring long-term coating performance and durability of the integrity of the yacht grey water tanks.


Shipyards, management companies, manufactures, applicators, consultants and independent laboratories all have a crucial role to play in the industry to avoid these issues. This involves not just improving and enhancing coating systems but also working on research and development programs to lessen the impact of fluids in these types of tanks.

The image at the left depicts the condition of a grey water tank in the vapor phase, significantly deteriorated. On the right, in the immersion there are no signs of deterioration and good adhesion observed after 1 year of a complete tank coating refurbishment.