Sugar plantation

Throughout the 17th and 18th century, sugar plantations were highly prevalent and profitable in the Caribbean. Typically owned by a single family, they were normally worked by said family's slaves, and guarded by a sizeable contingent of soldiers.

During the early 18th century, the Beckford and owned, between them, the majority of the plantations in the Caribbean. Because of the possible rewards obtainable from a successful raid, sugar plantations were a promising, if risky, target for pirates.

Reference

 * Assassin's Creed IV: Black Flag