I'm not totally sure about your line, but on RCI - you need to bring your bank info to the ship (proof of account/numbers/etc) and they will set up a wire account on the ship. This can take several weeks, but in the meantime, crew need to go out in ports to wire money. Looking at your run, you have Ft Lauderdale, St Thomas and San Juan - which all have places from which to wire.
Do you have a hiring partner to ask? Or perhaps see if there are Carnival crew pages on Facebook you can ask for sure?