Different companies have different titles for the position.
at Bouchard it’s Barge Captain and Mate
Reinauer Barge Captain is called Second Mate which is really stupid, but it’s a company run by tankermen.
The position is tankerman, and you will need a tankerman PIC endorsement to load and unload cargo at a minimum.
Some companies have eliminated this position and have a licensed mate handle the cargo. Most companies are trending toward having the tankermen live on the tug, especially on ATB units.
On the Mississippi the tankermen are sometimes not on a boat at all, and just drive to wherever barges are loading and unloading.
The last time I worked as a tankerman was in NYC for a small mom and pop. It was $415 a day.