The many masters in French lower-deck ranks

The hierarchy moves through major, principal master, first master, master, second master, and quartermaster grades. Their sailing-era logic is recognizable, though so many similar titles can be difficult for outsiders to distinguish. Six grades contain master in some form, so a literal English rendering can conceal rather than clarify a sailor's place in the hierarchy. The most junior mousse grade is tentatively connected with youthful apprenticeship, initial training, and short national-service experience, with an explicit caveat about limited direct familiarity with French practice.