How is it currently done in the US Navy?Their role as "ship's troops" was not, by training nor doctrine, to replace the naval infantry, nor to be the sum total of them, until after WW II, according to the Corps' own historians. It was to be the elite of the NI, and the bulk of the full-time NI. (Masters at Arms were likewise the shore patrol leadership, not the bulk of the shore patrol staffing, and were the SNCO's of the landed NI's naval troops.)