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Tuesday, December 1, 2020

Maritime Logistics Professional

Liquefaction of Iron ore cargo caused vessel to list & ground

Posted to Liquefaction of Iron ore cargo caused vessel to list & ground (by on January 20, 2010

Report of the investigation into the listing and grounding of m.v. Black Forest reveals that the accident was the result of liquefaction of cargo - iron ore fines

Investigation into the causes of grounding and subsequent listing of the 17,240 DWT Black Forest has only reaffirmed the dictum that the trade should have long term approach in establishing safety standards towards accident free image rather than profitability alone. The recent findings has brought to light that the transportation and loading of iron ore fines onto the vessel at New Mangalore port on the West coast of India was undertaken when the area was experiencing heavy monsoon. This caused liquefaction of the iron ore fines to take place resulting in the separation of moisture content and some kind of separated water-fines mixing.
Depending on mode and speed of loading, cargo geometry can have multiple peaks and plateaus explained a person close to the investigation. Unlike liquid cargo the mechanics of such moisture laden cargo in the ship’s hold is rather complex where the water drains into the hold bilges inducing mixing prospects with the cargo due to the ship dynamics such as vibration, weather, etc. (With conditions conducive to draining into bilges and pumping thereof, liquefaction is unlikely.) However, with condition unfavorable, separated water migrates to the surface and forms scattered puddles. This results in lower strata compaction with increased draining resistance and loose surface cargo with presence of water.
As ‘watchdog’ covering the whole investigation Captain John P. Menezes, the ship owners’ representative, stated, “Multi-purpose ship with lift-away pontoons, take more time to close hatches than modern bulkers with folding hatch covers. Small lists due to rolling / deballasting create surface water flow, truncating peaks / collapsing cargo and thus can result in huge sudden dangerous movements of the ship. By and large liquefaction adversely affects shipment part commercially / operationally and can lead to severe casualties beyond ship’s control. But by and large, it is initiated at the load port and gets aggravated during the voyage and may persist during discharge.”
Shortly after leaving port probably due to poor ballasting system in terms of integrity / pumping out, the vessel initiated de-ballasting during the voyage. The vessel commanded by a Chinese captain postponed dealing with hold bilges due to de-ballasting. Hence, there was upward migration resulting in scattered puddles of cargo during de-ballasting. The combined effects of liquefaction and unsatisfactory de-ballasting resulted in dangerous listing. “The vessel listed initially 3 starboard later reaching to 10starboard in one hour,” stated Capt Menezes. “Vessel was then beached at 17starboard list off Old Mangalore waters to avoid capsizing.”
According to the report it appears that earlier a Greek captain had refused the cargo. The Chinese captain of Black Forest accepted the cargo after being given the survey certificate, which is considered fraudulent as the survey was undertaken several days earlier when the cargo was in much better condition. Hence, the report observed that had the captain insisted on a fresh survey report seeing the condition of the cargo, the incident would not have occurred

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