NavList:

Navlist Visitor [Gary LaPook], you wrote: “The sunline procedure was the standard method for finding islands ………… Coutinho used it in 1922 crossing the South Atlantic.”

Please do you have a reliable reference for Coutinho and Cabral (let’s give the pilot some credit) using that method in 1922, and if possible, a link to a readable copy of their charts with tracks and position lines plotted.  I have not managed to find either.  Arthur J Hughes writing in ‘The History of Air Navigation doesn’t mention the use of any initial heading offset with respect to Coutinho and Cabral although he does mention it when describing Chichester’s NZ to Australia flight.  All he mentions is that Coutinho was a great celestial enthusiast whilst Cabral was a sticker for DR requiring flying accurate heading and speed and assessment of drift, which was an ideal combination.  Hughes also says that Cabral showed him their intended charted route before he left. Moreover, whilst the offset and sunline procedure is obvious on Chichester’s charts, the only rather smudgy part of Coutinho’s charts I’ve been to find online shows no such track offset or line of position.  I have a couple more books I’d like to check, but like many items in my life these days, I’m temporarily unsure of their position.  They’re bound to turn up soon while I’m searching for something else.  DaveP