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    Re: Historic Equinox LAN error: Ocean Navigator
    From: Frank Reed
    Date: 2015 Mar 20, 08:18 -0700

    Ed,

    I don't know more about that specific example, but there was a similar story recorded in a journal kept on the whaleship Morrison in 1844. The author is a passenger on the voyage from New London. The vessel eventually dropped off the author in Oahu in the Sandwich Islands (Hawaii) where he remained for some unknown time as a preacher. Like a logbook, this journal includes navigational information but also personal observations of events aboard ship, natural phenomena, and anecdotes of life aboard ship. The passage below was written in the mid-Atlantic...

    "Friday November 8th [1844]

    This forenoon we had squalls accompanied with rain. A little before noon it broke away so as to enable us to obtain an altitude of the sun & work out latitude. Found ourselves very nearly under the sun our persons at noon scarcely casting any shadow at all. In sweeping with the quadrant, found the altitude least at the north our latitude of course being greater than the declination. Our zenith distance accordingly changes its direction & instead of being north as it has been since leaving home it becomes south & the sun bears north. In calculating the Latitude we now add the zenith distance & declination instead of subtracting the less from the greater of them as we have hitherto done -

    In conversing with one of the crew a few evenings since, he related the following fact which occurred on board a whaling vessel in which he sailed a year or two since. They were on the voyage home from Ferdinand Noronha a small island off the coast of Brazil in 4 S Latitude. The vessel belonged in Provincetown on Cape Cod & was commanded by Captn Small. She had cruised during the summer for sperm off the West coast of Africa, South of the line. Thence they sailed to Noronha, which they left on the 11th of September 1843 bound to Massachusetts. They crossed the line on the 14th after which they had calms & made but very little progress until after the equinox on the 22nd . Capt S. having been south of the line whilst the sun was north. had of course a south zenith distance & a north declination & in obtaining his latitude had taken the difference between them. But not understanding the subject, although he supposed he must add them after the 22nd of September & accordingly did so. His ideas had probably become confused by the changes that had occurred very nearly at the same time. He had crossed the line thus changing his latitude, he had passed north of the line thus changing the direction of his zenith Distance, & the sun had crossed the line thus changing its declination. At all events after the 22nd he commenced & continued to add his declination & zenith distance in calculating his latitude. The consequence was that he made progress homeward in his Log book much more rapidly than he did in fact. The first thing however that troubled him was his Longitude. His latitude being too great affected his calculations for finding the ship's time, making that too small & of course his longitude too great. At length after a great deal of trouble with his chronometer, he concluded the instrument was very inaccurate & therefore entirely abandoned its use. According to his calculations it placed them as far west as Lake Ontario - Not knowing how to work a Lunar, he was entirely unable to find out where he was -

    At last he asked the assistance of his mates & time of his crew who had given little attention to Navigation, but they could afford him no relief. Supposing however their latitude correct they continued to sail North Westerly, keeping a sharp look out for land. Thus he kept on until his calculations placed him in 44 11' N or more than 2 degrees north of his place of destinat ion. He then changed his course and was steering South West for Cape Cod light when it occurred to him that he had mad a mistake in thus adding instead of subtracting the declination. this discovery solved the whole mystery. at the time it was made he was actually in 29 north & was heading direct for Bahama Banks. The intense anxiety of the crew occasioned by their total ignorance of their situation was now removed. To add to their distress during this season of gloomy doubt they had encountered a storm which had carried away all their topmasts; & they had also been upon short allowance both in water and provisions. However in a few days after getting upon their right course & repairing their broken masts they were further relieved by speaking a vessel which furnished them with supplies in due time after undergoing much suffering & incurring great danger from their own & their officers' ignorance of navigation, they arrived at home in safety.

    The name of the barque in which the above occurred is the Spartan. She still sails from T [P probably... for Provincetown]. After relating the substance of this account to our officers, Capt G. mentioned an instance of a similar mistake. An individual having the charge of a vessel, added in this manner for some time, when he should have taken the difference of the declination and Zenith Distance. But finding his calculations gave him greater headway than the light wind he was then having could possibly do, he was led to suspect, discover, and correct the error before it occasioned any mischief. Mr. Watrous the First Mate, also related the case of a similar blunder committed by a man now master of a whaling ship out of New London. In this instance however it was immediately corrected by comparing the work with that of another person who had performed it accurately. "

    Both the story that you originally described, and the one quoted above, sound to me like teaching stories. They're perhaps "once upon a time" fables designed to drive home a point for the student. Although this one appears to include lots of specifics, they're all second-hand details. Mistakes like this did occur, but the extreme versions where everything goes wrong and the vessel ends up hundreds of miles from where it is believed to be are "better stories". We see much the same thing with some 'urban legends' today.

    The Morrison journal entry is part of a fascinating journal with references to lunars and other navigation issues as well as astronomical observations of the Magellanic clouds and other phenomena new to that New England author. You can read it online in Mystic Seaport's digital library. There is a link to this on the main NavList page. At the top, go to the "Resources" menu. Select "Mystic Seaport Logbooks". Click through to the Mystic Seaport site. Then scroll down to "journal; Morrison". As of right now, this digital library site appears to be suffering some kind of outage, so you may need to try again later or find your way in from another "portal". 

    Frank Reed
    ReedNavigation.com
    Conanicut Island USA

     

       
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