Model Tests: LNG-Carriers in Ice

Abstract

Approximately on third of the world’s known and not yet exploited reserves of natural gas are in Russia. The overwhelming majority of these reserves are in Artic and Subarctic areas. But not only in Russia, also in other areas like Canada and USA, natural gas reserves are found in harsh and ice covered environments. As a consequence, the LNG ship technology is going towards Arctic LNG-Carriers. New developments in ice navigation, winterization and ship sizes are generating a new exiting challenge for shipping and ship building industries all over the world. Existing ice class regulations should be only considered as a first guide for designing ice-going vessels. Because the future performance in ice covered waters of new developed LNG-Carriers needs to be investigated in much more detail, therefore ice model tests are imperative. It is common practice guiding ships in ice-covered waters by using one or two icebreakers for wider LNG-Carriers. The LNG-Carrier is following in the broken channel of about 1.25 to 2 times the widths of its beam. For the model tests a parental level ice sheet of target ice thickness will be prepared according to HSVA’s standard model ice preparation procedure. In order to obtain a defined friction coefficient between the ice and the model hull, HSVA applies a special paint composition to the models of ice-going vessels. The channel will be broken with the help of two stock icebreakers towed through the level ice generating the most realistic wide ice channel. The prime objectives of such ice model tests are: • Evaluation of the icebreaking performance in a wide ice channel, • Propeller-ice-interactions and • how the ice is transferred aside and below the vessel.