OK. Maybe you are right, still we need some way of communication. What about signal flags? Like it done in real fleet. We can put them on the back side of balloon. They can be specific for different cases and have to be other, than customizing flags. For example - long and mono-colored. At last 4 - 5 signals like:
need help - red flag
steak together - blue flag
keep the distance - light blue
attack my victim - yellow flag
go to hell - black flag - this one for those who don`t want to play in command.
Flags are to be in captains menu.
Maybe there is the sense to make a lot of small colored flags with many different senses to choose, and if captain (or any other crew member) will look at them with scope - teem will get a message in text chat.
Besides, it can be good idea to organize voice commands like that is done in old CS game ("gogogo", "steak together team" and so on). I mean - you push the button, and then another to "say" something more or less usual.
"Need engineer", "hull on fire" or "enemy is on the left side"
And this is the way how people from different countries can communicate - captain is Japanese - he push the command reading hieroglyphic signs, and player hear it in the language of localization of the game, for example american engineer will hear it in english, russian gunner in russian and allemand pilot in allemande. The only trouble - we will need localization, or at least instruments of modifying some part of game content.