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Kieran Kelly wrote:

>  There are about 9/10 of them all armed with a sextant or
> quadrant. About four of them are wielding sextants. Since the film is set in
> 1805 I find this a bit difficult to believe. At that point the sextant was
> only coming into common use and would I believe have been a fairly rare and
> expensive item. I doubt if any English  warship would have carried four of
> them and certainly they would not have been entrusted to the tender care of
> a midshipman, who was only one rung up the totem pole from a common seaman.
> Am I right in this hypothesis?
>
> Furthermore, I read recently that until well into the 1800's, the noon
> sight - requiring less exactitude - was taken with the cheaper and more
> robust quadrant. The sextant was preserved almost exclusively for the more
> demanding lunar Distance where precision was vital.

You are probably right. The following may give you a rough idea about the
absolut numbers of navigational instruments as well as the proportion of
sextants and quadrants at an even much later time in the US.

According to a table in Steven J. Dick, "Sky and Ocean Joined", p.49, the Depot
of Charts and Instruments (the forerunner of the U.S.N.O) kept 100 sextants for
40 active ships in the early 1840s. Quadrants are not mentioned in this table
but in other places we read about a need for "eight sextants and four quadrants"
in 1832 or "12 double-framed sextants, 24 Quadrants", etc. The number of
chronometers, by the way, rose from about 35 in 1830 to 54 in 1835 and to 131 in
1846. For comparison: there were 600 to 800 compasses.

Herbert Prinz

   

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