The ship was anchored at New Orleans in the Mississippi river and due to berth shortly. Hence the chief officer requested the second officer to get him the vessel's draft. He had completed the for'd and midship drafts with a life vest and lifeline.
When he was about to descend the Jacob ladder for the aft draft, the stand-by AB advised him to use the lifeline, to which he replied, "Only one more draft to take; anyway I have my life vest on".
After taking the aft draft while coming up the ladder, the AB noticed the Second Mate struggling and taking frequent rests between rungs. Suspecting something amiss the AB told the 2/O to hold on, and went to get help to assist him.
When the help arrived after about 2 to 3 minutes, they found the 2/O missing from the ladder. An alarm was immediately raised. The Captain informed the agents and the coast guard. After some hours of searching the operation was given up due to darkness.
Sad to say his body was found after two days.
The proper use of a lifeline/safety line cannot be overemphasized.