ABS and the Russian Maritime Register of Shipping (RS) are to jointly develop of classification Rules for Arctic Liquefied Natural Gas Carriers under a wide ranging cooperative agreement between the two IACS members. The announcement was made during the 4th Annual Arctic Shipping 2008 International Conference & Seminar in . This is the first pairing of societies to create Rules for the liquefied natural gas (LNG) market sector. The principal elements in ice strengthening LNG carrier design are: strengthening of the hull; the interaction of the hull structure with the containment system; minimum propulsion power requirements and strength of the propeller.