Not sure, but I know one is definitely needed. On my last ship, we had a guy with a Chief’s license (all modes) and 32 years in the union occupying a permanent 3AE job. Doing the bare minimum (and doing that slowly) all the while claiming ignorance of various duties because he “was a steam guy”. It’s doubly bad because not only was he useless, but he was taking a 3AE billet from a new potential member.