In the first half of he 20th century and for a bit longer Instructor Officers were graduates entered purely for instructional and Met. duties. This was at a time when all Executive (later Seaman) officers were entered either at 13 (from 1949, 16) to Dartmouth or (from 1913) 18 ish as 'Special Entry' and thus only had a sub-A-level educational standard (although the RN did, later in their careers, try and improve on this, but only in ways which would not lead to degrees and therefore to the idea that they might leave and get a better job outside). Officers promoted from the Lower Deck by definition had even less education. It was the Schoolies who had to polish these pearls to a brighter shine; in the old sailing Navy they taught navigation to midshipmen and this thread continued, with Schoolies teaching pilotage at Dartmouth and then astro navigation with its concomitant spherical trigonometry later. NB Spherical Trig was not in any O or A level syllabus ashore. The Schoolies also had to run general education classes for ratings. How the Schoolies picked up Met I'm not sure but I suppose we fish heads were thought too thick to cope with it. As an aside, in the days of National Service a university-bound young man could get a deferment so as to complete his degree before donning the Queen's uniform. Some graduates sidestepped the pain of that a bit by signing for three years as a Schoolie, which meant they came straight into the Wardroom as an Instructor Lieutenant. Until 1956 pale blue cloth was worn between their stripes. However it was not until later that Schoolies suceeded to military command.
dit follows. One of these NS wonders, at RNAS Abbotsinch, had a grand passion for a Wren with watchkeeping duties in the control tower. As night fell, if she was on watch, he would go out to the Tower and hoot like an owl. She would switch the Tower lights off and on to show she still loved him. This being rumbled rather a large flock of owls foregathered .. oh never mind. Based on his time at this almost moribund Scotch air station he went on to become a prominent spokesman on Strategic matters.