Project summary

NGP was assigned to clean and inspect six box coolers on board MT Sohna during scheduled yard maintenance in Karachi, Pakistan. The job included manual marine growth removal, inspection of paint condition, pressure testing, and reinstallation of all units.

How we worked

Work began with a full mechanical cleaning using Valhall Gel and manual work. All coolers were treated in multiple rounds and cleaned using air-driven HP water spray. Damaged gaskets were replaced with new ones cut locally to original specifications. After treatment, the coolers were pressure tested at 4.5 bar with no leaks recorded. Final installation was carried out using chain blocks for controlled lowering into the seachests.

Results

All coolers were cleaned, tested and reinstalled with new gaskets. The pipe internals were flushed one-by-one with pressurised water. Tightening was done per NRF torque guidelines, and installation was completed without any damage. Cleaning was approved by the vessel owner during final inspection.

What we used

• Valhall Gel (NGP)
  
• Air-driven HP washer
  
• Custom-cut rubber gaskets (4mm)
  
• Torque system per NRF guidelines
  
• Manual pressure test setup (4.5 bar)
  

Reflections

This was a clean and well-executed box cooler service. The team followed a structured procedure, replacing worn components and ensuring all units were pressure tested and approved before delivery. A good example of mechanical cleaning and preventative maintenance delivered efficiently.