Navy Boatswain. It had definite practical uses in those days, many of which have now ceased to exist. The navy's boatswain's mate rating (which is what the navy calls its jobs) is one of the two oldest in this branch of the military, dating back to 1794.
The boatswain is chief of the crew, and as such is to see that every man is attentive to his duty. Boatswain's calls played by the u.s. The boatswain’s pipe (originally termed a call) dates back to the days of sail.