What is aftcastle?

An aftcastle is the raised structure at the stern (rear) of a ship, above the upper deck and behind the mainmast. It is typically used as a lookout post or for storage purposes. In the past, it was also used by senior officers as a living quarters or as a defensive platform during battles. Some traditional sailing ships have elaborately decorated aftcastles as a symbol of status. Today, the term is mostly used in reference to historical or replica ships, as modern ships rarely have this feature.