Hidden depths
I read with interest Craig Hardy’s article ‘Keeping a lookout using electronic navigation aids’ [YM, June 2018] on what I term ‘electronically assisted groundings’. Nowhere in the article does he question if the latitude and longitude for the reef or other atolls on the plotter are actually correct. I refuse to believe that every remote reef, island or atoll in the world has been recently surveyed. I remember, albeit 20 years ago, going into Lautoka in Fiji; the channel was two miles to the west of the electronic position. The chart was showing correct depths and positions relative to the land but incorrect as to GPS. One of the crew told me that we had two miles to run to the buoyed channel to Lautoka. I pointed out that we were one mile from the channel and that if we went two miles, we would be halfway up the runway at Nadi airport. He could not understand why this was the case. I pointed out that Captain Dampier (English explorer and navigator) or whoever’s chronometer was two seconds out when the area was originally surveyed, so the chart was out by two miles.
Nearly 50 years ago, when I was studying for my Master’s certificate, we were told firstly to always ensure that an alert visual watch was maintained and secondly, never assume that any one position placed on a chart is correct until it had been verified by a second. That is why three sights were always taken and then again checked by another officer. Nowadays, I obviously use plotting programmes on my yacht but I still try and use the Mk I eyeball whenever possible. David Buckpitt