DNV launches Class Note on LNG sloshing

Hamburg: DNV is launching a new LNG sloshing Class Note for membrane tank systems, which it says has been developed as a response to several technical challenges facing the sector. These include the advent of new large size LNG carriers, offshore loading/unloading and the likelihood of more partially filled tanks in respect of part cargoes (due to vessel size and growth of the spot market).

The guideline 'Sloshing Analysis of LNG membrane tanks' emphasises sloshing loads and tank system strengths for both normal and reduced tank fillings. It compares the sloshing load and strength of a new LNG carrier design or a carrier operating with partly filled tanks to the sloshing load and strength of the existing fleet of membrane-type LNG carriers that have a record of trading without sloshing damage.     

Announcement of the new DNV Class Note at the SMM show in Hamburg coincided with a warning in a sidebar conference on LNG shipping operations that the issue of sloshing would likely emerge in connection with the new, larger class of membrane carriers. Insurers were already eyeing these vessels warily, said Joachim Bake, superintendent of Bergesen Worldwide Gas, because of the value of acrgoes and the earlier occurrence of sloshing impact-induced membrane defects on certain Korean-built LNG carriers. [29/09/06]