Sea Chest Cleaning, Blasting & Coating Preparation – Port Side Repair
Overview
During a routine inspection, the vessel’s crew identified an active leak on the port side sea chest. Further investigation revealed that the internal strainer had worn a groove into the interior surface of the sea chest, compounded by advanced corrosion in the surrounding metal. Given the critical nature of sea chests and their constant exposure to harsh marine conditions, immediate corrective action was required to assess the extent of damage and prevent further deterioration.
Coastal Tank was brought in to safely clean, prepare, and document the condition of the sea chest so repairs could be properly evaluated and planned.
Containment & Environmental Control
To ensure a clean and controlled work environment, Coastal Tank deployed an industrial vacuum system to establish negative air pressure within the work area. This setup effectively captured all abrasive material and airborne dust generated during blasting.
By maintaining negative airflow, we were able to:
- Prevent dust migration into adjacent compartments
- Keep the hard space below the sea chest clean and contamination-free
- Provide a safe, dust-controlled environment for both the crew and surveyors
This level of containment is especially critical when working within confined marine spaces where cleanliness and safety are paramount.
Inspection & Repair Planning
Once blasting was complete, the sea chest interiors were left at bare metal condition, allowing marine surveyors to thoroughly evaluate the extent of wear and corrosion. With full visibility of the affected areas, surveyors were able to accurately assess structural integrity and recommend a precise repair strategy to the vessel’s captain.
This step ensures that repairs are based on confirmed conditions rather than assumptions hidden beneath old coatings or corrosion products.
Next Steps: Coating System Application
Following completion of the required metal repairs, Coastal Tank will return to:
- Profile all newly replaced or repaired metal surfaces
- Apply two coats of novolac high-solids epoxy to the sea chest interiors
The abrasive blasting process creates an angular surface profile that allows the epoxy system to form a strong mechanical bond with the steel. This coating system is specifically selected for its resistance to chemical exposure, seawater immersion, and long-term corrosion protection—providing years of reliable service in a demanding marine environment
Scope of Work
Our team was tasked with fully preparing the sea chest interior for inspection and future coating application. This included:
- High-pressure steam cleaning of the sea chest interiors to remove marine growth, debris, and surface contaminants
- Abrasive blasting to remove remaining coatings and fully eliminate corrosion
- Containment and environmental controls to protect surrounding vessel spaces
- Surface preparation to allow surveyors to inspect bare metal conditions
Best Practice Recommendation
Inspecting and maintaining sea chest coatings during scheduled haul-outs is considered industry best practice. Addressing coating breakdown early helps prevent accelerated corrosion and avoids costly structural metal repairs down the line. Proactive maintenance ensures the vessel remains protected, compliant, and operational between service intervals.