When I first learned to sail, I often needed to identify navigation buoys, ships and obstacles that were on the horizon. Field glasses/binoculars were useless, due to the narrow field of view and motion of the ship, which is amplified greatly.
What I learned was that the best way to identify objects on the water was to scan, to keep my eyes shifting. This scanning of the horizon somehow brings up anomalies, such as a buoy, that simply are not visible when staring straight ahead. What I catch are discrepancies to the monotonous horizon. I think that they are first identified through the corner of my vision, and once generally located, am able to see them with a fixed gaze. I used this technique for years without realizing it, and always surprising crewmates who had no idea how I could site objects so far away and indistinct.
The recent crash of the Malaysian airline was covered in the news, and in one report they cited that the airplane search crews were doing exactly what I had learned to do, to finding anomalies in the endless monotony of the vast Indian Ocean.
For me, before the days of GPS, sighting Cormorant Rock off Mattapoiset was my first definitive visual when crossing Buzzard’s Bay from Wood’s Hole. It was a dead north track and arrival signaled the completion of the deep water crossing.
Even with the GPS, I continue to scan the horizon, keeping visual confirmation of our location, and vessels that may have paths crossing ours…
Sailing Grounds of Vineyard Sound, Buzzard's Bay, Cape Cod and the Elizabeth Islands