Abstract
Two group of rubber have been renewed after the begining of service of the vibration damper on the main engine. The first renewal was after 5 years and 8 months from the installation and the second after 7 and half years from the first. The rubber used now is the third group over 2 years from the second. It was found out that the estimated values of shaft center with calculating the difference of the rubber-shrinkage correspond with the measured ones. So, the detailed investigation could be carried out for the variation of shaft center by the compound deformation due to heat, elasticity and plasticity and the creep of the rubber on each of group for long time. It happened sometimes that the variation of shaft center became about 1.0 mm with the difference of the environmental temperature, e.g. such as that of before starting and just after stopping engine. The value is the limit to the engine. Then the early large creep reduce like gentle slope after 10-12 months from setting new one
