To scuttle a ship is to deliberately sink a ship. The term is typically used in reference to one's own ship, and typically involves inflicting damage to the ship from within it to cause it to sink. In Puzzle Pirates, the term is often used in reference to Brigand King battles.
Scuttling a ship
While there is not a scuttle option for one's own ship in Puzzle Pirates, there are indirect ways to go about doing this. This can include sailing the ship into an Atlantis location or sinking flotilla and allowing it to be attacked. This technically does not constitute scuttling, as the pirate in question is merely sacrificing the ship by sailing it into a sinking hazard with no intention to defend or evade.
A scuttle option has been discussed, but there so far appears to be no intent by the developers to provide such an option for deed owners.
Scuttling Brigand Kings
When a royal for an island-owning flag is aboard a ship from their own flag during a sea battle with a Brigand King (BK) and wins that battle, they will have the option to scuttle that ship. If the royal chooses to scuttle the Brigand King's ship, they will provoke an attack on their island, causing the island to be blockaded the first available weekend immediately following the scuttling as of release 2008-04-22. If a flag owns multiple islands, the Brigand King will attack the closest.
The ability to scuttle a Brigand King's ship was first added in release 2007-06-26.