Do carrier-borne aircraft pilots count the seconds on the downwind leg of the carrier?
According to the F/A-18's manual, the pilot starts the 180° from downwind when abeam the landing signal officer's platform:


  With a 30-knot wind over the deck begin the 180° turn to the final approach when approximately abeam the LSO platform.


Here's the illustration (of course the ship is not fixed, it's moving):


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