NavList:

David I.,

There are at least two reasons for exchanging longitude and not chronometer time: Firstly, not all ships had a chronometer, but they were still interested in their longitude. Secondly, longitude changes much slower than chronometer time, so it is easier to exchange by e.g. signal flags. One example: Assume you are sailing at 10 knots on an easterly course at 60° latitude. Then your minute of longitude "ticks" once every third minute of time. But this minute of longitude corresponds to 4 seconds of time, i.e. longitude is 45 times "easier" to exchange correctly. Other courses, less speed and lower latitude gives even more time for leisurely signalling.

Lars