@warismydestiny:
zoro is the first mate that is much is obvious for everyone who doesnt need every small little thing confirmed by oda
-he was the first person to join the crew
-hes the stronges in the crew after luffy(seriously is there even 1 pirate crew in one piecewere the second strongest isnt the first mate)
-hes being shown as the rayliegh to luffys roger(both have a scar on 1 eye both use swords both are hard drinkers rayliegh waseven the first person to join rogers crew)
-but most important of all he can step up and take control when no one else in the crew can for example when ussop left and rejoined the crew (there are many other examples)even nami whos usually greta at taking command was completly useless
but people will still ignore all that and keep insisting the strawhats have no first mate lol atleast untill its co firmed in the story which it will be imo near the endin a one on o e confersation between luffy and zoro
Everything you say does indeed make sense, though the Mugiwara crew is not a "pirate" crew, they are a group of strong willed people with individual dreams on the same ship.
It's "anarchic" to a certain degree, "democratic" at the same time (remember how often the guys have to pick up the straws) and responsible, since everyone know what they have to do for the best of the crew.
There's certainly not a "chain of command", but something more similar to a "bond of trust".
Surely Luffy is the trust "glue", but everyone does his own and is trusted by the other members in the same way.
So yeah, Zoro is undoubtely the first mate, though, in the case of the Mugiwaras, it's a title more than a behaviour.
Usually the first mate is the coscience of the Captain, and the tie between the Captain and the Crew, but in the Mugiwaras Luffy is without restraint and Zoro sleeps in the meanwhile.
Zoro interpreted this "role" very few times, like in Usopp's departure or in Punk Hazard when he told Luffy to take things seriously.
He did that incredibly well, BUT he's not always focused on that and that's why Nami fills in the gap.
Last thing…
Chapter 19, page 8...that's Nami's usual doing, not Zoro's ;)