A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Frank Reed
Date: 2015 Jun 20, 16:13 -0700
I've created a new topic (as above) since this was starting to spin off from the "lifeboat" discussion. It appears that the Bligh discussion was abandoned, set adrift, you might say, but I think there's plenty of interest in this. Here are the previous messages on this topic from last week: Re: William Bligh, Navigator.
David Pike, you wrote:
"It’s now believed that William Bligh had slightly more equipment than he claimed"
Do you have a sense of who specifically believes that? And why do they believe this?
"Although his navigational achievement in the launch was remarkable, he didn’t actually have much more to navigate with while he was in Bounty."
I think William Bligh would be appalled by that statement! :) After the mutiny, he could not take his beloved lunars, and he could not consult that magic black box, the time-keeper K2. In short, he was thrown back to those dreaded days before the longitude could be found. Terribly demeaning, at the very least...
"We know from Bounty’s log that in her Bligh was running three positions, one based upon dead reckoning, one based upon longitude obtained using the chronometer K2, and one based upon a longitude obtained using lunars, presumably as a time correction to K2 (we never see Bligh’s detailed calculations)."
I think it's relatively clear how Bligh was using lunars and how the various accounts were being kept, but let's talk about the navigation aboard Bounty later. Back to the boat voyage to Timor...
"He certainly had a quadrant and possibly a sextant so, with declination tables, he would have been able to get latitude at noon. He was able to borrow Mr Peckover, the gunner’s, watch, which would might have given him an approximate and relative longitude until it broke approximately 2/3 way through the voyage. As far as is known, Bligh didn’t attempt any lunar calculations during the launch voyage, either because he didn’t have the ephemeris, or it would have been too much trouble."
They were not much trouble for someone with experience. If Bligh had a sextant and the Nautical Almanac, then he surely would have done lunars. He was good at them and clearly had solid confidence in them. Even if he had only a quadrant, he still could have gotten longitude by lunar, though quite a bit less accurate. And this would all have entertained him personally and given him and also the men in the boat greater confidence in their survival. The only explanation that makes any sense is the simple one: he did not have the Nautical Almanac (at least not for the current year). Other volumes frequently included data for the Sun's declination and the equation of time for a few years ahead. Moor's Navigator had such tables. But the only source for the lunar distances was the Nautical Almanac itself.
"1. Were one of the navigational tables which must have been used by Bligh in the launch and the set of lat & longs belonging to Mr Hallet one and the same document"
This I don't know. There were latitudes and longitudes in Moore's Navigator. As you say, though, the trouble with any of these tables in the era was the possibly huge inaccuracy in listed longitude and even some uncertainty in latitude. Certainly the position of Timor could be trusted reasonably well. And positions measured by lunars by Cook and his team (including Bligh) on the earlier voyages were reliable, but there were many low quality positions published in commercial navigation manuals like Moore.
You also asked:
"2. Is there any record of Bligh’s detailed calculations in the launch over and above those in his notebook? Without them, he must have had a brain on a par with an early, top of the market, hand held calculator."
I have not seen anything like that, and it's worth considering that he may have done the work on a slate, with no permanent record. But I don't see what calculations you're thinking of that would have been difficult to any significant extent. Don't forget that dead reckoning is dead simple so close to the equator. Within the level of uncertainty of the course and speed observations, the calculations can be done as if on a flat earth with latitude and longitude lines spaced evenly and equally, like on a common sheet of graph paper. Bligh didn't have modern "graph paper" of course, and we hope that the calculations do not really imply anything as difficult as would require a handheld calculator (see PS).
You closed with a recommendation of the Fateful Voyage web site: http://www.fatefulvoyage.com. I agree. That's a rich resource. One might even call it bountiful. There's also a digital copy of the logbook kept by Bligh aboard Bounty here: http://badc.nerc.ac.uk/data/corral/ships/bounty.html.
Conanicut Island USA
PS: I'm required to say that bit about the lack of evidence for a handheld calculator by the Temporal Council. But I can fill you in (they're probably not reading closely here). In fact, I completed my time machine last week. I had intended to deliver my method of working lunars to Maskelyne in 1765 and then stop off in 1880 and deliver hav-Doniol to Squire Lecky, but I was caught in a parity-reversing time eddy that damn near wrecked my time machine, scrambled my temporal navigation computer, knocked my inertial dampers offline, and dropped me in Tahiti in 1789. There were many benefits... many benefits.... But with my machine severely damaged I had to spend a few months making repairs and then return to the present. I left behind one gift for William Bligh. I handed him my Casio fx260 solar scientific calculator and said, "Don't open it unless you find yourself in a dire emergency. Keep it hidden. If the need arises, you'll figure it out..." When I returned to the present, I was amazed to learn that Bligh and his crew had, in fact, reached Timor. That's not how I remembered it!! Sadly my time machine's main vectorial-shunt circuits burned out when they returned to the normal-parity present.