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    Re: For want of a chronometer
    From: Frank Reed
    Date: 2022 Jun 1, 10:00 -0700

    The ON article is a re-telling of a famous story. Much of it, including the illustration and its caption, are taken directly from the Wikipedia article on the Arniston, here. Trouble is, the navigational aspects are speculation. The sources are labeled as "primary source" in the references to the Wikipedia article. That's misleaing. The six survivors of the wreck were not involved in the ship's navigation. The speculative "for want of a chrconomter" theory can be traced directly to Basil Hall. Hall was a prolific author and a great story-teller. His words, in other instances, were lifted liberally and dropped into Patrick O'Brian's famous sea novels (plagiarism? ...tut-tut, perish the thought). Here's Basil Hall's own account of the loss of the Arniston from his book "Lieutenant and Commander" (from gutenberg.org):

    In the year 1815, I accompanied a convoy of homeward-bound Indiamen from Ceylon, and a right merry part of the voyage it was while we ran down a couple of thousand miles of the south-east trade-wind; for these hospitable floating nabobs, the East India captains, seldom let a day pass without feasting one another; and we, their naval protectors, came in for no small share of the good things, for which we could make but a poor return. Along with our fleet, there sailed from Ceylon a large ship, hired as a transport by Government to bring home invalid soldiers. There were about 500 souls in her; of these a hundred were women, and more than a hundred children. I was accidentally led to take a particular interest in this ill-fated vessel, from the circumstance of there being four fine boys on board, sons of a military friend of mine at Point de Galle. I had become so well acquainted with the parents of these poor little fellows during my frequent visits to Ceylon, that one day, before sailing, I playfully offered to take a couple of the boys in my brig, the Victor, an eighteen-gun sloop of war; but as I could not accommodate the whole family, the parents, who were obliged to remain abroad, felt unwilling to separate the children, alas! and my offer was declined.

    Off we all sailed, and reached the neighbourhood of the Cape without encountering anything in the way of an adventure; there, however, commenced the disasters of the unfortunate Arniston, as this transport was called. She had no chronometer on board; a most culpable and preposterous omission in the outfit of a ship destined for such a voyage. The master told me that he himself was not in circumstances to purchase so expensive an instrument, the cost of a good chronometer being at least fifty or sixty guineas, and that the owners considered the expense needless. He also stated that on his remonstrating still more, and urging upon these gentlemen that their property would be ten times more secure if he were furnished with the most approved means of taking good care of it, he was given to understand, that, if he did not choose to take the ship to sea without a chronometer, another captain could easily be found who would make no such new-fangled scruples. The poor master shrugged his shoulders, and said he would do his best; but having often rounded the Cape, he knew the difficulties of the navigation, when there was nothing but the dead reckoning to trust to.

    During our passage from Ceylon, it was the practice every day, at one o'clock, for the Indiamen, as well as the men-of-war, to make signals showing the longitude of each ship by chronometer. Thus we had all an opportunity of comparing the going of our respective time-keepers, and thus, too, the master of the Arniston was enabled to learn his place so accurately, that if he had only kept company with his friends the Indiamen, each of whom was provided with at least four or five chronometers, the deficiency in his equipment might never have led to the dreadful catastrophe which speedily followed the loss of this assistance.

    It was late in the month of May when we reached the tempestuous regions of the Cape; and we were not long there before a furious gale of wind from the westward dispersed the fleet, and set every one adrift upon his own resources. The poor Arniston was seen at sunset, on the day the gale commenced, with most of her sails split, but not otherwise in danger, for she had a good offing, and the wind was not blowing on shore. Three heavy gales followed in such quick succession during the next week, that not only the ordinary course, but the velocity of the current was changed, and instead of running, as it almost always does, to the westward, it set, on the days in question, to the south-eastward. According to the most moderate allowance for the current, all circumstances being taken into consideration, any navigator might fairly have supposed that, in the five days which elapsed from the 24th of May to the 28th inclusive, his ship would have been drifted to the westward by the current at least a hundred miles. Our chronometers, however, distinctly showed us that we had been carried, not, as usual, to the westward, but actually to the eastward, a distance of more than a hundred miles; so that, in less than a week, there occurred upwards of two hundred miles of error in the dead reckoning.

    The master of the Arniston, doubtless, after making every allowance, according to the best authorities, and working by the most exact rules of navigation of which he could avail himself, naturally inferred that his ship was more than a hundred miles to the westward of the Cape, and he probably considered himself justified in bearing up before a south-easterly gale, and steering, as he had so much reason to suppose he was doing, straight for St. Helena.

    It is very important to remark, in passing, to professional men, that no ship off the Cape, and under any circumstances, ought ever to bear up, without first heaving the deep sea-lead. If soundings are obtained on the Bank, it is a sure symptom that the ship is not sufficiently advanced to the westward to enable her to steer with safety to the north-north-westward for St. Helena. It is clear the ship in question must have omitted this precaution.

    All that is known of this fatal shipwreck is simply that the Arniston, with a flowing sheet, and going nine knots, ran among the breakers in Struy's Bay, nearly a hundred miles to the eastward of the Cape. The masts went instantly by the board, and the sea, which broke completely over all, tore the ship to pieces in a few minutes; and out of her whole crew, passengers, women, and children, only half-a-dozen seamen reached the coast alive. All these could tell was, that they bore up and made all sail for St. Helena, judging themselves well round the Cape. This scanty information, however, was quite enough to establish the important fact that this valuable ship, and all the lives on board of her, were actually sacrificed to a piece of short-sighted economy. That they might have been saved, had she been supplied with the worst chronometer that was ever sent to sea, is also quite obvious. I am sure practical men will agree with me, that, in assuming sixty seconds a-day as the limit of the uncertainty of a watch's rate, I have taken a quantity four or five times greater than there was need for. Surely no time-keeper that was ever sold as such by any respectable watchmaker for more than thirty or forty guineas, has been found to go so outrageously ill as not to be depended upon for one week, within less than ten or fifteen seconds a-day. And as I have shown that a chronometer whose rate was uncertain, even to an extent five or six times as great as this, would have saved the Arniston, any further comment on such precious economy is needless.

    This is the second time I've posted these quoted paragraphs. The last time was so long ago that NavList was still a "list" (a mailing list). From that same historical era (in both senses), here's my account, with follow-up messages, of Basil Hall's story of lunars about the Erin in 1807.

    But isn't that wonderful! Now we know what happened to the Arniston from Basil Hall himself, who was part of that same convoy. But he was not there. Hall was not aboard the Arniston, and he is only speculating about what happened aboard the vessel after the convoy dispersed. And there are basic factual errors; he says there were a hundred women and a hundred children aboard. Other sources disagree. Basil Hall's account is essentially a parable, a story designed to teach us a lesson.

    Are there alternative interpretations of the events? A chronometer is not magic. If the storms were so severe, the Arniston might have been without a sight of the Sun for the entire duration of those few days after the convoy was scattered. He does, however, make the excellent point that a relatively common good watch or a very poor "chronometer" could have served to keep the time for at least a week. That's true, and who knows: maybe they tried that? Unfortunately, without a morning or afternoon Sun sight for local time, Greenwich time would have been useless.

    So what really happened? Your speculations, models, opinions, wild theories?? Anyone? 

    Frank Reed
    Clockwork Mapping / ReedNavigation.com
    Conanicut Island USA

       
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