But I have never heard of aviation directions being given in terms of "Turn left to S by SE -- no, not SE by S, silly pilot";
Mid 1976, during the 3rd Cod War. Low level off Iceland in a Nimrod, being directed onto something by a trawler. First instruction, in a strong Northern accent was " Coom two points to port, lad."
Port no problem, had to think about "two points". Got it right - the next instruction was "Steady as tha goes, lad".
Perhaps, as Reefrat put it, he had concerns about the numeracy of the helmsman.