Global ice load prediction for the icebreaker using 6-DOF motion measurement method

Abstract

A global ice load acting on a hull of an icebreaker with a six degrees of freedom (6-DOF) inertial measurement system method was described in this paper. The 6-DOF inertial measurement system treat the ship as a rigid body and measures whole ship motions, and the global ice loads were calculated with the data measured by full-scale ice sea trials of Korean ice breaking research vessel (IBRV) ARAON during her voyage in 2015. To calculate the maximum global ice load, the point of impact (POI) approach and the center of gravity (COG) approach were used, respectively. The differences of the calculated results using the POI and COG approaches were from 254% to 1,794%. Comparing with the resultant forces from strain gauges which ranged from 0.11 to 0.8 MN, the global ice loads from the POI approach were from 59% lower to 239% higher than forces from the strain gauges, and the global ice loads from the COG approach were up to 1,907% higher than the forces from the strain gauges. The calculated global ice loads from both the POI and COG approaches were within the range of an empirical ice load estimation formula under normal operating conditions.