Failure of pipework in fuel tanks

What happened?

Water ingress into a fuel tank was discovered to be from leaking pipework. Water ingress was reported into a fuel tank from two seawater lines running through the tank. Engineers investigating a high-level alarm on the fuel tank initially thought it was due to vessel movement. But upon inspection of the pipework, a leak was found on a sea water pipe approximately 150mm outboard from the Pump Room bulkhead.

What went wrong? What were the causes?

There was a hole of around 13mm diameter in the pipe, which had caused seawater leakage into the tank and thus, a rise in level. Fuel was transferred from this tank to the port side settling tank and shortly after starting the transfer, the port side fuel separator tripped out. The 3rd engineer went to clean the strainer and quickly realised that a large amount of water was present in the system. A check on the settling tank drain confirmed that there was water present.

The cause was failure of pipework installed on the vessel at build stage.

What lessons were learnt? What actions were taken?

• Clarification of fuel tanks on vessels if pipework lengths run through tanks;
• Inspection of pipework in tanks for integrity through visual and ultrasonic thickness baseline measurements.

On the IMCA website, entering corrosion into the safety flash page search bar generates 60 results which members may wish to check for themselves.

Members may wish to review the following incident:

• Huge leak discovered in fresh water system