Ballast Tank Pitting Rebuild
Deeply pitted seawater ballast tank cold-filled and lined for immersion service without cutting plate.
What was failing
A ballast tank sits under constant seawater immersion, alternately flooded and emptied, and that cycle drives deep, localized pitting into the steel. As the pits advance, the wall loses thickness at scattered points across the plate and the internals, and the corrosion keeps concentrating wherever bare steel is exposed. Left untreated, the pitting perforates the plate and the tank can no longer hold ballast or keep the vessel trimmed safely. The owner needed the steel protected and the pitting arrested without cutting out and replacing plate, which means hot work that is hard to justify inside a confined ballast tank.
How AAS approaches it
We start by cleaning the tank internals back to clean, profiled steel so the repair bonds and the corrosion has nowhere left to sit. We cold-fill the pits with a Belzona 1000 Series composite, bringing the scattered metal loss back to a flush, sound surface with no welding and no heat in the tank. Once the substrate is solid and shaped, we apply a 5000 Series immersion-grade lining over the full surface, sealing the cold-filled pits and the surrounding steel under one continuous barrier keyed to seawater service. The work stays cold and confined-space friendly from start to finish.
Assess and map
We enter the tank, map where the pitting is deepest, and confirm seawater immersion service so the lining is keyed correctly.
Surface preparation
We clean and abrasive blast the internals to a profiled surface so the cold-fill composite and the lining both bond to bare steel.
Cold-fill the pitting
We fill the pits with a 1000 Series composite, bringing the scattered metal loss flush with no welding and no heat in the tank.
Apply immersion lining
We apply a 5000 Series immersion-grade lining across the full surface as one continuous barrier over the steel and the filled pits.
Inspect and return to service
We check the lining for continuity and hand the tank back ready to take ballast again.
The result
From the job
Repair and protection work of this kind, performed by AAS crews across Louisiana.
Capabilities used here
Where this work happens
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