NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: The shipwreck of Admiral Shovell
From: J Cora
Date: 2007 Sep 6, 20:02 -0700
Let me start by saying that I am not knowledgeable about the details of the
historical incident, except that I seem to remember that the accident
prompted the Admiralty to give much more attention to improving
both charts and the practice of navigation. I believe their efforts were
successfull in addressing both concerns.
After reading some of the posts in this thread, it seems that the state
of the art in angle measurement was either crossstaff or backstaff.
I am not familiar with either instrument but accounting for the
capabilities of the tools what errors were likely in measuring declination?
It seems that there were tables of declination of good accuracy at
that time.
Also in the thread it seems that the charts of the time placed the
scilly islands further north by 10 miles than was the case. I am
wondering though, when the charts in use at that time were actually
produced; as it is not unusual today to use charts with data over
50 years old ( particularly soundings). Was it possible that more
accurate information could have been available to the fleet had
there been a system like todays notice to mariners?
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From: J Cora
Date: 2007 Sep 6, 20:02 -0700
Let me start by saying that I am not knowledgeable about the details of the
historical incident, except that I seem to remember that the accident
prompted the Admiralty to give much more attention to improving
both charts and the practice of navigation. I believe their efforts were
successfull in addressing both concerns.
After reading some of the posts in this thread, it seems that the state
of the art in angle measurement was either crossstaff or backstaff.
I am not familiar with either instrument but accounting for the
capabilities of the tools what errors were likely in measuring declination?
It seems that there were tables of declination of good accuracy at
that time.
Also in the thread it seems that the charts of the time placed the
scilly islands further north by 10 miles than was the case. I am
wondering though, when the charts in use at that time were actually
produced; as it is not unusual today to use charts with data over
50 years old ( particularly soundings). Was it possible that more
accurate information could have been available to the fleet had
there been a system like todays notice to mariners?
On 9/4/07, George Huxtable <george@huxtable.u-net.com> wrote:
Frank Reed seems to have got himself remarkably overheated about
this matter, and I can't imagine why.
Let's recount the story, for those who don't know what he is on about, from
page 12 of Sobel's book "Longitude"(1996).
Shovell "... had been approached by a sailor, one of the "Association"'s
crew, who claimed to have kept his own reckoning of the fleet's location
during the whole cloudy passage. Such subversive navigation by an inferior
was forbidden in the Royal Navy, as the unnamed seaman well knew. However,
the danger appeared so enormous, by his calculations, that he risked his
neck to make his concerns known tothe officers. Admiral Shovell had the man
hanged for mutiny on the spot."
| George, you wrote:
| "So what Sobel did, unforgivably, was to relate such an implausible legend
| as a fact."
|
| UNFORGIVABLY. lol. IMPLAUSIBLE lol. You do enjoy hyperbole, George. But
| let's get back to facts
|
| How do you declare it all so implausible? How do you KNOW? Merely because
| Gould said "yeah, right, i don't buy it" albeit, in Latin? The whole point
| that I was getting at last week was how do we KNOW what is fact and what
is
| not in the terrible tale of the shipwrecks on the Scillies in 1707. You
| weren't there (were you?). I wasn't there. Dava Sobel wasn't there. Hell,
| Rupert Gould wasn't there...! So what really happened. It's well worth
| exploring considering that the 300th anniversary is coming up so soon...
Sobel reported the story as fact. Did she provide any evidence? No. Can
Frank prove it's truth? He makes no attempt to do so.
I did not claim that the story is untrue (though I consider that highly
likely). I described it as implausible, which it is, and explained why it
was so implausible in writing-
" No captain or admiral had such summary powers. And the flagship was due
into her home port in the next day or two."
| George, I think your biggest problem with the whole "back story" (what I
| have recently called the social side of the legend) is that you personally
| simply had never encountered it before you read Sobel's book. It was, as I
| have said, very commonly told just the way she described it in the 1970s
and
| 80s and probably before. Can you, George, cite examples of historians of
| science, or historians of astronomy, or nautical astronomy, or whatever
(!)
| who told the story much as Sobel did, or do you confirm my suspicion that
| the entire 'social side' of the thing was new to you before you read
| "Longitude"?
I really don't see the relevance of Frank's "suspicion", in assessing the
truth of the tale. Yes, I had read that story before I read "Longitude". So
what? There seems to be something of a personal attack going on here, for
reasons I cannot fathom.
| The next step, of course, after we have enumerated the legendary details,
is
| to consider how one would actually verify or falsify the components of the
| legend of the shipwreck of Admiral Shovell. There is, in fact, a process
for
| dealing with legends and the underlying facts. This process has been
applied
| to the Shovell story... a suprisingly long time ago [anyone?? it is (some
of
| it) on google books...]
Well, go on, Frank. Apply that process, then, whatever it may be. Don't keep
us in suspense.
Next, in Navlist 3174, Frank replied to Fred Hebard as follows-
===================
Fred, you wrote:
"I looked at the figure. If they could have had a good longitude,
they would have been better off. "
Did you look at the full diagram in the article? George clipped it just to
the left of a couple of small X's in the original diagram. Do you see what
those little X's represent?? They change EVERYTHING. That's where the
Scillies would be relative the fleet's DR positions assuming something as
trivial as a different catalogued source for the longitude difference
between the Isles of Scilly and Cape Spartel. Longitude was the primary
error in the fleet's position.
-FER
PS: I want to be very clear on this: I do not mean to imply that George
clipped the diagram to remove the X's. He clipped it there, quite
appropriately, to save on image size. However, I would contend that W.E. May
made the X's small, and almost un-noticeable, in order to minimize their
significance, which would have been a distraction from the point he
(W.E.May) was trying to make.
=====================
What on Earth is all this about "clipping the diagram"? The attachment I
sent, with a slightly magnified view of the diagram in the original paper,
was complete, border and all. So was the copy I (and presumably everyone
else), received back, as Navlist 3148. Nothing was clipped, nothing even
appeared to be clipped.
George.
contact George Huxtable at george@huxtable.u-net.com
or at +44 1865 820222 (from UK, 01865 820222)
or at 1 Sandy Lane, Southmoor, Abingdon, Oxon OX13 5HX, UK.
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