User blog comment:GrilloSama/Jinbe For 1st Mate/@comment-2A02:587:741F:3A00:E151:51B8:F255:E3A8-20170925140359

The fact that does not validate anything like that, is the straw hats don't have a hierarchy similar to other pirate groups. Luffy is the captain but anything else is aformalistic. Luffy didn't even agree to name his "sons" by drinking the cup of sake. The thing that you got wrong is that Luffy seeks freedom throughout his journey and does not really rely on terms like "first mate". He hasn't even thought of stuff like that. So why should we care and analyze it when the captain himself doesn't have a hierarchical structure like that ?