No machinery fails without giving proper symptoms. As engineers we must have the ability to sense it at the right time. So basically all machinery failures are human failures. Even a material failure is a human failure in the design stages!!
Here the story is a temporary M/E failure because of bad work practice.
I joined as 2/E at one of the Indian ports on a twin screw VLCC. A new 3/E also joined next day and we sailed out after completing discharge. Our next port of call was Fujairah. On arrival Fujairah stand by given for mooring.
Myself, 4/E and a 5/E were on duty. After stopping the engines astern movement was given and we found both engines not starting. Repeated kicks were of no use and C/E was informed and he came down. For the nest 5 minutes we couldn't find any reason and slowly our heart bents started increasing. Suddenly like a flash a sentence came to my mind which last 2/E told me while we were walking near the engine at the time of handing over.
"We used to keep this cock shut". That was the sentence. Control air supply line to reversing cylinders of both engines used to be kept shut after maneuvering. We opened the cocks and the main engine started.
This was the practice on the ship and only 2/E, 3/E & one 5/E knew it. The 2/E & 3/E had signed off, and the 5/E who shut it after last the last maneuvering was off-watch, asleep. The 4/E, the other 5/E, and the C/E were not aware of this practice.
LESSON: Prepare a comprehensive handing-over note!! It is very important.