"Nickel ore cargoes, which commonly emanate from ports and mines in tropical regions such as Indonesia, often have a very high moisture content and have previously been linked to a number of serious bulk carrier casualties involving loss of life due to liquefaction during the voyage," it said.
Intercargo manager David Jones said the danger is that a nickel ore cargo can absorb moisture when it sits at quayside, especially during stormy monsoon weather.
"The problem is when it goes into the ship when it's moist, as time goes on ... you get the water separating from it", which affects the balance of the ship, he told Reuters.
"What you could find is you could have a free surface effect, which leads to stability issues," he said, adding that it could result in capsizing. Intercargo said an independent surveyor would be able to determine the transportable moisture limit, which it said must be done before a nickel ore cargo is loaded onto a vessel.
"Ship owners, operators and charterers should exercise extreme care when dealing with nickel ore," it said.
Japan's Coast Guard said it was unclear what had happened to the Panama-flagged Nasco Diamond, but empty rafts and oil slicks were seen near where three crew members were rescued, about 340 km (210 miles) south of the island of Iriomote.
Another crew member, of a total Chinese crew of 25, was found, but it was not clear on Thursday whether he was alive. A further seaman was found dead. (Reuters)
