A more thorough explanation:

Definition: Bilboes (bil-bohz) is a historical device used for punishment at sea. It consists of a board with holes that secure an offender's hands and feet. It is similar to stocks used on land. It is also an iron bar with sliding shackles for confining the ankles of prisoners, especially on ships.

• A pirate was put in bilboes for stealing from the ship's stores.
• The captain ordered the crew to put the mutineers in bilboes to prevent them from causing any more trouble.

These examples illustrate how bilboes were used to punish offenders at sea. Pirates and mutineers were often put in bilboes to prevent them from escaping or causing trouble. The device was used to keep prisoners in place and prevent them from moving around the ship.