A.a safety line attached to a man working over the side
B.used to measure water depth
C.used to slow the headway of a barge
D.used to measure the overhead height of a bridge

A.is a deck fitting used to shackle gear to the deck
B.permits easy jettisioning of deck cargo in an emergency
C.prevents stress concentration in the bulwark
D.provides opening through the bulwark for mooring lines