The song serves several purposes in the story:
* Character development: The song is primarily associated with Long John Silver, the pirate cook who is the story's central antagonist. His hearty singing and leadership qualities are highlighted through his performance of the shanty.
* Atmosphere and setting: The song establishes the rough and adventurous atmosphere of the story, evoking the harsh reality of life at sea for pirates.
* Symbolism: The song's lyrics are open to interpretation. Some believe they represent the dangers of the sea and the pirate's desire for treasure. Others see it as a reflection of the crew's reckless behavior and their ultimate fate.
* Entertainment: The song provides entertainment for the reader and the characters in the story, acting as a break from the suspenseful plot and the looming threat of danger.
It's worth noting that the specific number "fifteen" in the song is not significant to the plot. It's likely a traditional element of the shanty, chosen for its poetic rhythm and rhyme.
The song has become synonymous with *Treasure Island* and is often used to evoke the image of pirates and the adventure of sailing the high seas.