Contaminated Cargo Happens
During a joint survey with Harden Marine Associates we noted the following; while offloading cement powder in bulk from this cargo vessel, the unloading arm (red arrow), which functions as an auger (giant Archimedes screw) and vacuum arrangement sucking up about 500 tons of cement powder an hour, malfunctioned.
This is the business end of the unloading arm, the opening at the suction end is approximately 3 feet in diameter. The cement powder is vacuumed from the hold into a series of large pressure tanks and then blown into silos, seen on the right of the photo.
It was found that the auger had been jammed by a piece of corroded steel, the source of which was initially a mystery.
A review of the ship's records revealed that, prior to loading the cement cargo in Greece, a load of scrap metal had been transported from the U.K. to Turkey. Prudently, the cement company had ordered a "Hold's Cleanliness Inspection" prior to loading the cement and contracted an established local cargo survey company for the task which was completed and an inspection report provided stating that the holds were examined and found to be
"... washed clean and dry, free from previous cargo residues and other foreign matter...".
However, our survey found several pieces of apparent scrap metal, similar to the piece which had lodged in the unloading arm, on the coaming of the No. 3 hold.
Additionally, we found that the "Hold's Cleanliness Inspection" had been accomplished by one surveyor who inspected Hold Nos. 1, 2, 4 & 5 in a 90 minute time frame (22.5 minutes/hold) and Hold No. 3, the following day, which took 25 minutes to inspect.
Given the scrap metal residue found on the hatch coaming and the relatively short time allotted for the hold inspections (each hold was approximately 90 feet long x 90 feet wide x 54 feet deep with internal longitudinal and transverse framing), it was our considered opinion that the "Hold's Cleanliness Inspection" had not identified pieces of scrap metal residue from the previous cargo and these contaminated the cement powder cargo and were, subsequently, ingested by the loading arm causing the jam and damage to its internal components.
Yes, stuff happens, but it doesn't necessarily have to.