Improvements in medium speed engines of recent design over their predecessors are significant in terms of operating cost and reliability. It is demonstrated that virtually all measures to achieve these improvements affect the crankshaft bearings, in many cases to a degree which makes the bearing the critical component for inspection and repair intervals.
The developments which have taken place in bearing design and materials have resulted in higher fatigue strength, higher wear resistance even when operating on heavy fuel oil and a generally higher degree of reliability. Some of these developments, the most important being the Miba-Rillenlager design, and the experiences with them are described.
An analysis of the cost factors investment, regular operation and breakdown consequences leads to the conclusion that the most economical overall solution is the bearing with the highest safety margin.