NavList:

David,

You asked: "Would typical marine navigators of the time know anything about such things? It is something that a land surveyor would have learned."

Marine navigators would not generally have known about occultations as timings are not easy to observe from the moving deck of a ship just like the moons of Jupiter.  Worsley used the Textbook of Topographical and Geographical Surveying by C. F. Close  https://books.google.com/books?id=IDBRAAAAYAAJ

Physicist Reginald James does deserve kudos. He independently reduced the occultation timings and it was he who worked with astronomer A.C.Crommelin on return to the UK to adjust the the longitudes to account for systematic errors in position of the Moon as discussed in our paper. A link to it and further explanation can found on this post http://fer3.com/arc/m2.aspx/Will-anyone-ever-find-Shackletons-lost-ship-Stuart-feb-2022-g52047
More than you could ever want know about Worsley's occultation timings can be found here https://www.canterburymuseum.com/assets/DownloadFiles/Navigation-of-the-Shackleton-Expedition-on-the-Weddell-Sea-pack-ice.pdf

I am seeing news reports about the 5NM as being a reflection of Worsley's fantastic navigational skills but although he was obviously a master this figure says nothing about his abilities. The position he reported was the noon position 19 hours after Endurance sank with no attempt having been made to account for the drifting ice in the interim. In longitude he probably got lucky in that his apparent tendency to underestimate how slow his working chronometer was running is compensated by errors in the Moon's position in the NA,

Regards,
Robin Stuart