| Abstract | The MOTAN inertial measurement system was used to determine whole-ship motions and accelerations at the stern of the LOUIS S. ST-LAURENT during the October 2000 ice trials. A total of 43 ice impact events were recorded during the trials, most of which involved secondyear and multi-year floes. Impact speeds ranged from 2 to 16 kt. Since the objective of the October 2000 Trials was to examine propeller-ice interaction, data from the MOTAN sensor, which was installed near the ship舗s centre of gravity, were used to compute the whole-ship motions at the ship舗s centre propeller, in the stern. During the 43 events, maximum accelerations in heave, sway and surge were 1.1 m/s², 1.9 m/s² and 1.0 m/s² respectively, at the centre propeller. The events produced a maximum roll of 7.6°, compared to maximum a pitch and yaw of 1.8° and 1.5°, respectively. Maximum accelerations in roll, pitch and yaw were 2.8 deg/s², 1.8 deg/s² and 1.5 deg/s² respectively. Results showed no apparent relation between impact speed and the measured whole-ship motions. Very few of the impact events qualified as symmetrical, head-on impacts where ship motions are primarily in heave and pitch; roll and yaw motions were a significant component of most of the impact events. |
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