Sting in the tail

摘要

In recent years, shaft alignment has been a particular area of concern for tankers. The current solution to this problem combines relatively short intermediate and tail shafts directly coupled to the engine flywheel at the forward end, supported by an intermediate plummer bearing and passed through and supported by the forward and after stern tube journal bearings at the aft end. Within the constraints of contemporary tanker design, this arrangement makes for a very short, stiff shaft line arrangement. Two main problems present themselves: first deriving a satisfactory alignment through the stern tube bearings and secondly, attaining an acceptable level of shear forces and moments at the diesel engine coupling in order to achieve proper crankshaft alignment.