Questions on tankerman pic


I’ve got a job lead with my cousin on small OSV’s in LA. They transport methanol to rigs. If I get a tankerman certification, I’ve got a job, and they will work with me getting my transfers done.

RiverSchool in Memphis has the soonest PIC course, but it is for barge. Does the OSV come under Barge or Tankship classification? The port captain for my cousin said that on this particular vessel I would be on they either need a master of a certain grade or a tankerman. I am not aware of all the particulars, but the short version is that the class begins on the 11th and the next class I can find is in Jan, and I need to get started as soon as I can. Will a “DL barge” cover OSV, or do I need to find a “tankship” class?