From Pollywog to Shellback: Crossing the Line
A time-honored Navy tradition, the crossing the line ceremony celebrates a Sailor’s first time to cross over the equator on a U.S. naval vessel. Sailors who have already crossed the line are nicknamed (trusty) Shellbacks, and those who haven’t… (slimy) Pollywogs.
During the initiation ceremony, Pollywogs are brought before King Neptune and his court, including Davy Jones, and are given certificates announcing their proud new status as Shellbacks. This fun ritual is often thought of as a morale booster during long stretches of time at sea.