AN ANALYSIS ON THE CHANGE OF SHIP SPEED ACCORDING TO ICE LOAD SIGNAL IN CONTINUOUS ICEBREAKING AND RAMMING

Abstract

Recently, the research activities by domestic and overseas researchers using the Korean ice-breaking research vessel, ARAON have been actively conducted. The ARAON regularly operates for research activities in the Antarctic and the Arctic Ocean every year. She conducts many scientific and engineering tasks including ice load measurement, investigation of the properties of material strength for sea ice, and icebreaking performance test during her voyages. Such tests provide important data for studying icebreaker. Ice-breaking mode is determined by conditions of sea ice and ice field, and it is divided into ramming and continuous icebreaking. When the icebreaker meets thick ice or icebergs, the ramming is conducted. At that time, the ship speed is generally slower than that of the continuous icebreaking. The ARAON conducted icebreaking performance tests at the Amundsen Sea in Antarctica in 2012. Many strain data were measured in the ramming and the continuous icebreaking. This study was based on the strain gauge signals measured by the ARAON during the research voyage in 2012 in the Antarctic and 2010 in the Arctic. The signals measured from repetitive ramming under the heavy ice condition in 2012 in the Antarctic Ocean were classified into the five profiles. And the classified ice load signals were analyzed with a focus on raising time, half-decaying time and total time duration. Also, the signals measured from continuous icebreaking in 2010 in the Arctic Ocean were analyzed in the same way as the ramming data. Finally, the time histories of ice load signals were summarized from the viewpoint of speed change at the time of ice load, and two data sets were compared.