Maneouvering Experiments in Ice on a Single Screw Tanker

Samsung Heavy Industries (SHI) and NRC’s Institute for Ocean Technology (IOT) collaborated on a project to predict the performance of a new design for a Suezmax size tanker that had acceptable open water performance but was also capable of operating in ice. The resulting hull form was a single screw, single rudder design with a bulbous bow, modified for operation in ice. An important design consideration is the ability of the ship to manoeuvre in different ice conditions. This paper presents the results of manoeuvring experiments in pack ice and level ice, using a free running model. Three distinct power thresholds were identified that must be exceeded before the ship would execute a steady turn in ice. Yaw rates acceptable for navigation in ice were obtained with an installed power of 17 MW in pack ice, for the load and ballast drafts. The hull did not manoeuvre well in unbroken level ice. Power well in excess of a practical, economic level was required to manoeuvre the ship in unbroken level ice, even though it proceeded in a straight line in the same ice conditions with an acceptable power level.