When a ship crosses the Equator, those sailors who have already crossed it must initiate those sailors who have yet to cross.  An old and nearly cruel ritual acting to bring sailors together, it also provides lots of sea stories.  

HISTORY
For sailors the world over, crossing the Equator means that the sailor leaves the ranks of the landlubber (a person who works and lives on land) and becomes a real sailor, a shellback. The cost of the transformation doesn't come cheap. The pollywog must be beaten, humiliated and tortured by those that have gone before. Only after a day of degradation at the hands of the old Shellbacks does the pollywog become a Shellback too. The oldest sailor who has crossed the equator becomes Neptunus Rex and presides over the "ceremonies". It's all in good fun and the reward is a huge certificate, signed by the ship's master attesting to the fact that the sailor is now a Shellback.

CROSSING THE LINE
OR TURNING POLLYWOGS
INTO SHELLBACKS

The Crossing the Line Ceremony is steeped in naval history and (conduct) for decades when U.S. Navy warships cross the Equator passing into the Southern Hemisphere. Those who have crossed the equatorial line on past voyages and have successfully completed the ceremonies earned the title of honorable shellback. Those who have yet to cross the equator (consider) pollywogs (a larval frog or toad).

Traditionally the festivities begin at sunset the day prior when a skull and cross bones flag (break) over the forecastle of the ship as the legendary Davy Jones and King Neptunus Rex arrive to query the ship entering into their sacred waters. Basically, the night before the ship crosses the Equator, Davy Jones appears to greet all pollywogs, and to read the "Charges" against the pollywogs and issue the punishment to each pollywog (basically what type of costume  (wear) the following morning, how to behave in front of King Neptunus, etc). All pollywogs are considered guilty by the fact that they are simply unexperienced "pollywogs".  

"I am Davy Jones, messenger to his Royal Majesty Neptunus Rex, Ruler of the Raging Main. I demand to know what this ship is, what course you  (steer) and by whose authority you dare to trespass within our Royal Domain", shouts loudly over the ship's speakers. The Master of the ship greets King Neptune upon his arrival. "A Sailor's welcome to you, King Neptunus. It is a great pleasure to have you aboard," he says over public address system for all hands to hear. "The displeasure is all mine", Neptunus gruffly responds. "Your ship is sorely infested with nefarious and slimy pollywogs. A situation which my Royal Party (intend) to correct by  (make) them fit Shellbacks for my raging main," Neptune continues.  

King Neptunus  (invite) to a pollywog talent show created especially for his entertainment. Pollywogs perform short theatrical episodes and songs to entertain King Neptune and ship's honorable shellbacks who are usually dressed as pirates. Pollywogs must navigate through obstacle courses (make up) of cargo nets, ropes or greased fenders. Once successfully completing the obstacle course, the pollywogs appear before King Neptunus and his court to be questioned as to why they should be allowed to be honorable shellbacks. After (satisfy) the Royal Courts questions, the pollywogs are sent to a cleansing pool where they washed off the pollywog slime and emerged honorable shellbacks.

Of course, in commercial cruises things are easier: One of the engineers on board is usually dressed as a baby. The ceremony culminates by a visit to King Neptune's Royal Court, where every pollywog gets to kiss the "Royal Baby's Belly"!!