Sure. One plotline could be a young orphan on an island is 'adopted by default' when a passing pirate crew decides to take them in after seeing their potential. The orphan then has to learn the ways of the pirates and deal with the crew's various personalities.
Another example is that a character who was left behind by their original group is found and 'adopted by default' by a rival group. This leads to a lot of internal conflict as the character struggles with their loyalty to their old group while also starting to care for their new 'family'. They might be in a position to either betray their new group or find a way to reconcile the two sides.