I’m sorry, but with the exception of Billy and Scott, sweet cinnammon rolls too good for this world, too pure, who are clearly  Hufflepuffs, (maybe also Abigail and Thomas, who might be Ravenclaws or Gryffindors, but we don’t know that much about them)  everyone from Black Sails is a Slytherin - Flint, Vane, Silver, Eleanor, Max, Anne, Jack, Miranda. They are all resourceful, ambitious, cunning,  self preserving and in search of power/wealth/fame.