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    Re: When did "time sights" fade away?
    From: Frank Reed
    Date: 2011 Jul 12, 18:56 -0700

    Hello John,

    You wrote,
    "I went to sea in 1961 as an indentured deck cadet in British merchant ships. Our navigation training was hands on from the start and developed from that already undergone in our pre-sea nautical colleges. By 1961 time sights were definitely a thing of the past in the School of Navigation (Warsash) and in Royal Mail Lines of London. I suspect that it was completely obsolete elsewhere in British merchant ships, but I am happy to be corrected."

    Thank you. Very interesting!

    That's consistent with my 'working model' on the history of this (I don't have enough evidence to call it more than that which is why I am asking). The major navies were all teaching New Navigation by the early twentieth century but apparently with much less emphasis in the USN than in the Royal Navy. There was apparently much more conservatism in merchant marine navigation instruction, and there were plenty of people still learning the Old Navigation right through the Second World War. What fraction? That I couldn't guess, except to say that it was a "significant" fraction. Naturally there were many exceptions, and I have seen a logbook from a British merchant vessel of the 1890s where they were already doing three star fixes (which generally means New Navigation). Sometime after 1945, navigation instruction seems to have converted completely to the LOP methods. So then it was just a matter of time. For an "old salt," at least on a slower vessel, there was no compelling reason to change the game unless there was some licensing requirement (i'm not aware of any), so time sights continued in diminishing use until the last of the navigators taught during the 1940s retired from the sea, presumably by the end of the 1960s.

    You also wrote:
    "Incidentally, our position lines were invariably obtained using 5-figure logs and the cosine/ haversine formula. For an acceptable, but lesser precision, some of us began to use Burton's 4-figure tables and the cosine/versine alternative, which, with experience and a good pro-forma, was quicker than many so-called short method tables, but obviously not as speedy and convenient as HO 249/AP3270. Azimuths were calculated using ABC tables."

    That's really interesting. Even as "New Navigation," these methods would surely have been counted as rather old-fashioned by 1961. Not that they wouldn't work, of course. And that seems to be a long-standing feature in the history of navigation. Methods don't get thrown out until the generation who first grew to love them finally stops teaching them.

    -FER

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