In June 1998, two of our vessels were increasing speed during the maneuvering speed range following departure from port, when an unusual vibration occurred in the high pressure turbine resulting in the deformation of the rotor. It is generally accepted that a sufficient warming-up period for the main steam turbine engine in the start and speed up phases will help to avoid any unusual vibrations. However, turbine manufacturers have not issued any specific guidelines for warming-up procedures or completion of the warming-up operation. The main turbine engines currently installed on board vessels put in service have no devices to monitor turbine casing temperature or expansion to help indicate when sufficient warm-up has taken place. This investigation had the objective of establishing more precise guidelines for the warming-up of main steam turbine engines, in order to prevent vibration-induced damage when sailing out from ports. The results of this investigation are based on data gathered from simple thermometers and expansion measuring devices installed on turbine casings, which measured the thermal changes in high pressure turbines as propulsion engines were used in port departure.
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