Class society DNV said today that the damage to the VLOC Vale Beijing was not caused by any global strength issue or by the effect of single pass loading. The vessel had developed cracks in its hull when loading a shipment iron ore in northeast Brazil in December.
“Calculations performed by the classification society DNV demonstrate that the damage on the Very Large Ore Carrier (VLOC) Vale Beijing was not caused by any global strength issue. DNV does not believe that single pass loading (covered by the class notation EL-2) contributed to the damage.” – DNV
DNV added that the Vale Beijing incident is not related to a general structural problem for VLOCs. The determination is presumably a huge sigh of relief for Vale, which has for 19 of the 400,000 ton iron ore carriers on order.
DNV says that calculations show that the cause of the damage is most likely related to the local buckling strength in some areas of the web frames in the aft ballast tanks however that conclusion is subject to the results of the ongoing investigation and the follow-up survey after the cargo discharge and dry-docking.
As a safeguarding measure DNV also reviewed other VLOCs classed by DNV, including those ships under construction, but they did not reveal any structural insufficiencies in the VLOC designs.
STX, which is the owner and operator of the Vale Beijing, has started an “extensive action plan for repairs” on the Vale Beijing and has said that the damage is fully repairable.
So what exactly is single pass loading?
[Single pass loading, also known as single-pour loading] is a method of ballast control that is synchronized with the cargo loading, scientifically deballasting the ship during loading in a way that balances the forcesinduced by the incoming cargo. Potential hull loading stress problems can occur due to the manner in which ore cargoes are loaded and due to the amount of cargo which is loaded in an individual hold. READ MORE ABOUT SINGLE PASS LOADING