What You Didn't Know About Life On A Submarine

"Shellback"

 "Shellback" is a nickname given to sailors who have crossed the equator, often as part of a traditional naval ceremony known as the "crossing the line" ceremony.

The ceremony is a time-honored tradition in which sailors who have not previously crossed the equator are initiated into the "mysteries" of the sea by King Neptune and his court. During the ceremony, the "pollywogs" (sailors who have not crossed the equator before) are subjected to a series of rituals and tests designed to prove their worthiness to become "shellbacks" (sailors who have crossed the equator).