STUDY OF DOUBLE-HULL TANKER LOLLING AND ITS PREVENTION

Lolling is an uncontrollable list caused by inadequate transverse stab ility in the upright condition. With the advent of double hull tankers , lolling incidents have begun to occur, usually while loading or unlo ading cargo. These lolling incidents have damaged loading arms and pie rs and resulted in ship damage. There is also the risk of injury or de ath to personnel, a risk of fire, and a risk of polluting oil spills f rom damaged loading facilities. This study considers the problem of lo lling of double hull, single tank across tankers in the 35,000 DWT to 150,000 DWT range. This is the size range of tankers which have experi enced incidents of lolling. Below this range are mostly product tanker s which have greater cargo tank subdivision. Above 150, 000 DWT, stren gth and tank size considerations dictate against the single tank acros s configuration The study recommends that new tankers be required to h ave sufficient intact stability to prevent the occurrence of lolling, preferably by design without having to consider cargo or ballast loadi ng sequences. The study also provides an approach on how to demonstrat e that sufficient stability is available under all loading conditions possible.