NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: David Thompson's Navigational Technique
From: Frank Reed CT
Date: 2004 May 31, 22:12 EDT
From: Frank Reed CT
Date: 2004 May 31, 22:12 EDT
Bruce S wrote:
"There has been a lot of chauvinistic puffery about Bowditch. But I don't believe he had any part in it. In any event, the puffery shouldn't obscure the fact that his "Navigator" was top notch. Bowditch deserves all the credit he got. It's just that he sometimes gets credit for the wrong reasons."
I agree with all of that. In addition, Bowditch (or his publisher, Edmund Blunt) deserves credit for convincing navigators that literally anyone could do lunars and use them reliably in practical navigation. Well, if you buy the book, that is. The success of Bowditch (the book) was salesmanship as much as seamanship.
Later editions of Bowditch, including recent ones, are primarily responsible for the suggestion that Bowditch was responsible for some revolutionary change in the way lunars were calculated. Quoting from the edition available online:
" A reliable marine chronometer had been invented some 60 years before, but the prohibitive cost, plus the long voyages without opportunity to check the error of the timepiece, made the large investment an impractical one. A system of determining longitude by “lunar distance,” a method which did not require an accurate timepiece, was known, but this product of the minds of mathematicians and astronomers was so involved as to be beyond the capabilities of the uneducated seamen of that day. Consequently, ships navigated by a combination of dead reckoning and parallel sailing (a system of sailing north or south to the latitude of the destination and then east or west to the destination). The navigational routine of the time was “lead, log, and lookout.”
To Bowditch, the mathematical genius, computation of lunar distances was no mystery, of course, but he recognized the need for an easier method of working them in order to navigate ships more safely and efficiently. Through analysis and observation, he derived a new and simplified formula during his first trip."
Frank R
[ ] Mystic, Connecticut
[X] Chicago, Illinois
"There has been a lot of chauvinistic puffery about Bowditch. But I don't believe he had any part in it. In any event, the puffery shouldn't obscure the fact that his "Navigator" was top notch. Bowditch deserves all the credit he got. It's just that he sometimes gets credit for the wrong reasons."
I agree with all of that. In addition, Bowditch (or his publisher, Edmund Blunt) deserves credit for convincing navigators that literally anyone could do lunars and use them reliably in practical navigation. Well, if you buy the book, that is. The success of Bowditch (the book) was salesmanship as much as seamanship.
Later editions of Bowditch, including recent ones, are primarily responsible for the suggestion that Bowditch was responsible for some revolutionary change in the way lunars were calculated. Quoting from the edition available online:
" A reliable marine chronometer had been invented some 60 years before, but the prohibitive cost, plus the long voyages without opportunity to check the error of the timepiece, made the large investment an impractical one. A system of determining longitude by “lunar distance,” a method which did not require an accurate timepiece, was known, but this product of the minds of mathematicians and astronomers was so involved as to be beyond the capabilities of the uneducated seamen of that day. Consequently, ships navigated by a combination of dead reckoning and parallel sailing (a system of sailing north or south to the latitude of the destination and then east or west to the destination). The navigational routine of the time was “lead, log, and lookout.”
To Bowditch, the mathematical genius, computation of lunar distances was no mystery, of course, but he recognized the need for an easier method of working them in order to navigate ships more safely and efficiently. Through analysis and observation, he derived a new and simplified formula during his first trip."
Frank R
[ ] Mystic, Connecticut
[X] Chicago, Illinois
