Reply To: SS Southern Cross (1955) – Maiden Voyage Logs

[Frank Scott]

For celestial navigation the classic ocean passage routine until the advent of GPS was morning stars (fix); forenoon sun-sight, intercept run to Meridian Passage (running fix); run to afternoon sun-sight (running fix), evening stars (fix). SS Southern Cross would almost certainly also have done long-by-chron as well. Obviously that was in perfect conditions, and in reality poor weather could prevent some or all of the sights in a ‘day’s work’.

The UK Merchant Navy of that era did not trust rapid sight reduction tables, indeed deck officer examinations all required the use of Burton’s / Norie’s Tables.

The Royal Navy by contrast shifted to rapid sight reduction tables (HD 486), and was not keen on Long-by-Chron. Some RN navigators used the RAF rapid sight reduction tables (AP 3270), which were even quicker, particularly for star-sights.