One of the inspirations could be the real pirate ships. Pirate ships were a crucial part of their lives. The show might have taken inspiration from the design, how they were sailed, and the functions of different parts of the ship. Another could be the pirate code. Pirates had their own set of rules, and this could be reflected in the show's portrayal of how the crew behaves and interacts.
The real - life pirates' diverse backgrounds could be an inspiration. Pirates came from all walks of life - some were former sailors, some were escaped slaves, etc. This diversity is shown in the characters of the show. Additionally, the concept of pirates seeking freedom on the open seas is a real - life idea. They were not bound by the same laws as on land and could create their own identities. 'Our Flag Means Death' likely takes these elements and shapes them into its unique story.
Well, real - life pirate rivalries are likely an inspiration. In history, pirates often fought over territory, treasure, or just had personal vendettas. This could be seen in the show where different pirate crews have their own agendas and sometimes come into conflict. Also, the idea of pirates being outcasts from society and creating their own communities on the sea is a real - life aspect that the show probably builds on. They had to fend for themselves, find food, and deal with the elements, all of which might be incorporated in some form in the show.