Fifteen Men on a Dead Man's Chest Pirate Song
The most famous words are from the first four lines of this pirate song are :

Fifteen men on a dead man's chest
Yo ho ho and a bottle of rum
Drink and the devil had done for the rest
Yo ho ho and a bottle of rum.

The Robert Louis Stevenson novel "Treasure Island" was published in 1883.

The words and lyrics of the first line of the pirate song "Fifteen men on a dead man's chest" are explainable. Dead Man's Chest is a tiny island that forms part of the British Virgin Islands in the Caribbean Sea. Pirate legends of the Caribbean claim that the notorious pirate, Edward Teach ( Blackbeard ), marooned 15 of his pirate crew on 'Dead Man's Chest' as a punishment for their mutiny and desertion. All pirates had their own Pirate Code of Conduct .  Article VII of the Pirate Code agreed by Bartholomew Roberts ( Black Bart ) and his pirate crew in the Shipboard Articles of 1721 stated:

He that shall desert the ship or his quarters in time of battle
shall be punished by death or marooning

The Pirate Code of Blackbeard stated that each pirate who was marooned should be given a cutlass and a bottle of rum. The scenes in the movie 'Pirates of the Caribbean' were therefore based on fact. The pirate hero, Captain Jack Sparrow, was given a pistol instead of a cutlass when he was marooned by his pirate shipmates.

The Pirate Song Tradition
The custom of singing, or chanting, various Pirate Songs was an extremely important part in life of a pirate. The pirate song was sung, or chanted, to accompany the hard and sometimes tedious tasks that had to be performed as part of the daily tasks of pirates. A pirate song would have been chanted, rather than sung, and the words of the chorus would have accompanied a heave or pull for a task such as raising the anchor on the pirate ship. The Pirate song was known as a sea shanty. The tradition of the pirate song raised morale, encouraged team work amongst the pirates, and gave them the opportunity to express mutinous sentiments.

The Pirate Song - the Sea Shanty
The term 'Sea Shanty' might originate from the French worded 'chanter' meaning to sing resulting in the chanty or shanty. However, the pirate song was chanted, rather than sung so this might also have been associated with the meaning. There were different kinds of pirate song or sea shanties.

• The 'Capstan Shanty' or pirate song accompanied raising the anchor of the pirate ship
• The 'Short Drag Shanty' or pirate song accompanied raising the masthead or trimming the sails of the pirate ship
• The 'Halyard Shanty' or pirate song accompanied raising the heavy sails of the pirate ship ( Sails hung from wooden cross-pieces called yards - thus haul -yards or the Halyard shanty
• The 'Windlass Shanty' or pirate song also accompanied raising the anchor of the pirate ship
• The 'Pumping Shanty' or pirate song accompanied pumping out the water, emptying the bilge
• The 'Forecastle Shanty' or pirate song was sung in the quarters of the pirate crews. The appropriate pronunciation for this word is fo'ksul. The forecastle is the forward part of the main deck
• The 'Celebration Shanty' or pirate song were sung pirate ship to celebrate victories or great accomplishments during the voyage of the pirate

The Pirate Song - the Chantyman or Chanter
The Pirate Song, or sea shanty, was lead by a 'chantyman' or 'chanter' who chanted the words of the pirate song while the pirates performed an arduous task. The pirates joined in with the chorus of the pirate song by shouting the well known chorus lyrics back. The importance of the 'chantyman' is once again highlighted in the Pirate Code agreed by Bartholomew Roberts ( Black Bart ) and his pirate crew. Article XI stated:

"The musicians shall have rest on the Sabbath Day only by right.
On all other days by favour only."
 

The Pirate Song

To the mast nail our flag it is dark as the grave,
Or the death which it bears while it sweeps o'er the wave;
Let our deck clear for action, our guns be prepared;
Be the boarding-axe sharpened, the scimetar bared:
Set the canisters ready, and then bring to me,
For the last of my duties, the powder-room key.