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Frank,

In regard to the frequency with which Joshua Slocum took lunars, which
you have said is low, based in part on this log, I might note that the
ship possessed a chronometer.  It was ships lacking chronometers that
really needed them, such as Slocum's, although lunars were also used to
rate chronometers.  Additionally, the whaler made port every few
months, and stopped at the Galapagos.  Her chronometer(s) undoubtedly
was rated whenever she did so or made island landfalls in mid-Pacific,
where the position of the island had been established carefully.

Fred Hebard

On Dec 18, 2003, at 3:12 PM, Frank Reed wrote:

> Last week I wrote:
> "While I'm here, I can elaborate a bit on one of those logs. The first
> mate's
> (?) log from the maiden voyage of Mystic Seaport's whaleship, the
> Charles W.
> Morgan, has miraculously survived. The ship left New Bedford in
> September of
> 1841 and returned home when the barrels were full of oil in January of
> 1845.
> This was a typical length for a whaling voyage in mid-century. She
> spent most of
> this time in the Pacific and made port every few months in Peru or
> California.
> The vessel also stopped a number of times in the Galapagos to pick up
> the
> ingredients for turtle soup. In those 39 long months, there is one
> "longitude by
> lunars". The rest are "by chrono". But there are a couple of terse
> references
> to officers "working lunars" which make it clear that the ship's
> navigators
> were aware that they needed to keep in practice. This level of usage
> is about
> what you would expect: c.1840 is often cited as the time period when
> lunars had
> become decidedly secondary in navigation. "
>
> I was *wrong* about the count of lunars being "only one". Right after
> I posted this message, I started having doubts since I had personally
> verified only a few months of the log and the rest was hearsay.
> Fortunately, the log of the Charles W. Morgan has been digitized
> recently and it is now available in the online library at Mystic
> Seaport's web site
> (http://www.mysticseaport.org/library/initiative/FunderList.cfm?
> FundingAgent=Andrew%20W.%20Mellon%20Foundation).
>
> There are 22 longitudes by lunar in that log in the period from Sep.
> 6, 1841 to Jan. 2, 1845. Here's a complete list of lunars/luners with
> the dates if you want to take a look at them yourself. Notice the
> clustering in certain periods when someone aboard must have taken a
> special interest in the technique. These periods are usually separated
> by gaps of four to six months when no lunars were taken at all.
>
> 1841/11/17
> 1841/11/21
>
> 1842/04/16
> 1842/05/15
> 1842/07/11
>
> 1843/01/06
> 1843/01/08 (being worked, no lon)
> 1843/01/23
> 1843/01/24
> 1843/05/04 (being worked, no lon)
> 1843/12/15
> 1843/12/16
> 1843/12/17
>
> 1844/01/14
> 1844/03/10
> 1844/03/12
> 1844/03/26
> 1844/03/28
> 1844/08/04
> 1844/10/03
> 1844/10/07
> 1844/10/20
> 1844/12/13
> 1844/12/14
>
> There are also a number of other logbooks from other vessels which
> they've digitized recently, and they include some really fascinating
> navigational details. You could explore for years!
>
> Frank E. Reed
> [X] Mystic, Connecticut
> [ ] Chicago, Illinois
>

   

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