There sure as shit was until recently. That was the whole reason Chief Mate was as far as you could advance on OSV’S. Why people like myself, Anchorman, and anybody else had to get on something not operating under Subchapter L, if we wanted to advance.
It has now been worded in CFR stating that the person next in line to the Master is defacto the “Chief Mate.” Now you have a whole separate dilemma of getting a special “letter” from your company stating you were “chief mate.” Because the COI just calls for a gaggle of Mate or Mates…
-You had a Chief Mate discharge, that’s a horse of an entirely different hue.
-I’m also sure they run your seatime against your discharges or seatime letters in MISLE.