Question 11Motor Plants - 1st Asst/Chief

The correct answer is A) tend to rotate with the journal. When a main propulsion diesel engine crankshaft bearing lacks sufficient 'crush', it means the bearing shell is not tightly fitted into the engine block. This allows the bearing shell to rotate along with the crankshaft journal, rather than remaining stationary. This rotation can lead to accelerated wear and failure of the bearing. The other options are incorrect because: B) the bearing would not pound under load if it is rotating with the journal, C) a thinner babbitt layer would be more appropriate for a rotating bearing, and D) the bearing would actually be less lubricated than one with sufficient crush, as the rotation prevents the oil film from properly forming.