July 2018
I learnt the mathematics of earth-centred astronomy as a surveyor in the 1960s and took astronomical observations by theodolite on a number of occasions. A few of them were actually in earnest - i.e., to establish orientation in the field.
In 1983, before heading off from Gladstone, on the Queensland coast, to New Caledonia, I dug out my old astronomy notes and programmed a Hewlett-Packard calculator to do the sight reductions. How this worked out is told in the article "The two-body fix at sea."
Back in Queensland after sailing through Vanuatu and Solomon Islands, I got a job at a big construction site at Moranbah. There was some sort of union agreement that there would be no overtime at the site which, in that remote location, left me with a lot of spare time. I sent for some technical astronomy material from the Royal Greenwich Observatory and mucked around programming another calculator, the Sharp EL-512. It was "long-by-chron" which means it computed longitude and azimuth for an estimated latitude. I put in an Aries almanac (which is simple) and wrote an instruction manual. It got a good workout on the next voyage from Gladstone to Darwin.
I thought it might have commercial prospects but my wife Fran and I were on our way to sail around the world so from Darwin I wrote to a bloke in Brisbane named Roy Rado who sold some programs for Casio calculators. He was a clever programmer but his operating procedures were very complicated and I asked if he was interested in what I had. He didn't reply.
We were late for crossing the Indian Ocean and Fran found she could get work as a schoolteacher so we postponed the circumnavigation. We parked the vessel, "Mijo," a 28 foot fibreglass Twister (overgrown Folkboat), among the mangroves of Sadgroves Creek and moved ashore. Later we put it on the hard and a couple of years later we sold it and moved to Perth, ending our circumnavigation plans.
Mucking about in Darwin, I managed to fit a sun almanac into the EL-512. I was proud of myself for it really is a very small programmable calculator. I gave it a name, "Sunflair," and wrote an instruction manual and began conducting private classes in celestial navigation using it. The EL-512 is a fairly low price machine and I thought I might offer a companion computer to be called "Starflair" for computing star sights.
I kept putting the almanac mathematics through the algebraic wash, and getting my head deeper into the subtleties of the design of the Sharp EL-512, and the day came when I fitted both sun and Aries almanacs into it. Now I was even more proud of myself. Fran asked me what I was chuckling about and I told her I thought it should logically be called "Stunflair." She wasn't that impressed and later came up with "Merlin."
I ran a few courses but it's possible I learnt more than the students did. It was still early in the history of hand-held electronic calculators and the experience gave me insight into the learner's mind and insight into how electronic computing can alter procedures. This influenced both calculator design and instruction manuals.
For reasons explained in "The two-body fix at sea" I abandoned long-by-chron in favour of Marq St Hilaire (i.e., the standard intercept method). The resulting machine was pretty straightforward. The calculator had four program buttons: #1 was the star almanac, #1 + #2 was the sun almanac, #3 gave the azimuth and #4 gave the intercept. That was about as plain as celestial navigation could be. All the basic data were held in memories so if you did multiple shots of a body you just had to put in the next clock time and sextant altitude and after a few seconds you read off azimuth and intercept.
The EL-512 is so primitive, the programs in it can't be read. So if a program doesn't compute as you intend - common with a developing program - you can't say whether your written-out program list contains an error or you mis-keyed one of the steps as you entered it. So you clear the machine and try again. You keep redoing it till you explain the problem or get it right. The upside of this design is good security as the program can't be read by anyone at all. The full Merlin program is reproduced here but at the time it was such a secret that we kept no correct paper copy of it.
I managed to talk the Sharp Corporation in Sydney into supplying EL-512s and I wrote a manual and advertised it in Cruising Helmsman magazine. Lo and behold, people sent cheques in the mail. I took the first few Merlins to the post office but then had second thoughts and there in the shopping centre I unpacked them and tested them once more. I myself still didn't quite believe that you could reliably have azimuth and intercept in a few seconds.
We used to program them ten at a time. We would line up 10 calculators side by side on a board about a metre long and then use the parallel action mechanism I fitted to the upper edge of the board to press ten keys simultaneously.
The first ones were priced at $75. We hadn't a clue about wholesaling and retailing and the price went to $99 then quickly to $119. A year later, after talking to a retail merchant, we upped it to $148 to allow us to sell in shops. To us, buying the machines from Sharp for something like $40, it seemed a rip-off. We wondered if anyone would buy it but (lo and behold) sales increased.
The fun thing about the Merlin was that you could compute sights as fast as an observer could take them. This only became clear after doing it, standing at Nightcliff beach with a student taking sunsights and telling the student whether the intercepts were consistent. I realised then that celestial navigation consists of entering clock and sextant readings into the computation process and recording azimuth and intercept. This wasn't possible with most devices which required a lot of other numbers to be entered. It is very simple: those other numbers should be held in the machine waiting for the next observation. Most machines required them to be re-entered every sight. The only other navigation computer that got this right was the was the powerful and expensive CN2000 designed by University of NSW surveying professor George Bennett. Also, you should not have to enter both time and altitude. Just enter clock time and let the machine do its thing and then, when it has found the computed altitude, enter the observed altitude. That makes the computation a prediction, gives learners insight, and gives teachers a way to manufacture examples.
For a while we photocopied the manual (the lounge room covered in piles of pages being sorted) but it seemed to be a viable business so we got the manual professionally printed. Fran flew off to England and the US and found us agents there. And then, after thinking things through - after all, we were sailing bums, not business people - we sold the boat, moved to Perth and set up there, working out of our home. That was 1986. We bought two IBM personal computers and a printer. The hard drives were 20 megabytes which was so massive there was no way anyone could ever use it all. (The EL-512 had one eighth of a kilobyte.)
I began to put together the Merlin II on the Sharp PC-1248. With a capacity of 8K it allowed some flexibility and was consequently more complicated. It was ready for Christmas 1988. The very first orders were packed in courier bags waiting to be picked up when one of the people who had a prototype rang up. He had found a fault. A programmer tests and tests and tests but still something can slip through and this fault was serious. What luck that he rang then and not a couple of hours or days later. I was able to unpack those orders, fix the machines and they went out to the customers that afternoon. No further errors turned up but I kept photocopying the manual for several months and made some minor improvements.
By this stage we were a lot more sophisticated as business people. We were importing Chinese sextants and I had taken a trip to the factory in China and also called on Sharp in Japan (and given the thumbs down to their proposed replacement for the EL-512) and when it came to Sharp supplying the PC-1248 one of their Perth sales executives visited and we sat around and discussed the market, meaning the retail prices of rival products, and decided on $229 both in Australia and in the US. What we were paying for the unit never entered the discussion. We were soon posting, by airmail, cartons of them to Monte Midkiff, our agent in Seattle.
The fun thing about the Merlin II was its speed. Sun and star sights take four seconds. The first moonsight takes 16 seconds but subsequent moonshots, if they are within ten minutes of the first one, take only four seconds. The other machines on the market took a minute or more for a moonsight. The reason Merlin II is so quick is because I had a mate, Gary Faas, who had sort of X-ray vision for the interiors of Sharp calculators and I was thus able to exploit the machine-language possibilities. The abovementioned Roy Rado advertised a navigation computer on the same Sharp PC-1248 and I discovered he was distributing advertising material saying my moon computation was approximate. I wrote him a nice letter pointing out that he knew better than that.
Over the next few years Fran got herself another university degree and I ran occasional courses in celestial for classes of up to eight pupils. The course was four weeks with two evenings a week. The first lesson was use of the sextant. We did star observations the next clear night and for that I set a mirror (about two feet square, off a bathroom cabinet I think) on the ground and levelled it as an artificial horizon. Worked well. All told I ran about twenty courses. There was also a weekend afternoon at Fremantle measuring the altitude of the sun as it sank toward Rottnest Island.
I had an elderly mate, Eddy Edwards, a former RAF pilot who had flown Catalinas on anti-submarine patrols in the North Atlantic, who gave individual classes in celestial and I thought that this is what I would do in my dotage. The GPS put paid to that idea. We celestial black magic merchants had been at it for a couple of centuries but the GPS busted our racket.
In the late eighties I got interested in tables and developed the S-Table, based on Ageton, which computed azimuth and intercept from a dead reckoned (not assumed) position. I had further plans for it but they were wrecked when the governments of Ronald Reagan and Margaret Thatcher nationalised celestial navigation. Yes, it's true: the British and US Almanac offices in cahoots with the good ol' boys of the "US Power Boat Squadron" (not a genuine navigator among the lot of them) included, as a give-away, a set of sight reduction tables in the Almanac. The tables were/are useless and had actually been a commercial failure but giving them away put an end to my plans. You can get some idea of the incompetence of the Almanac Offices by reading the article "The Nautical Almanac's Faulty Calculator Instructions." Note that because it was published in the Journal of the Royal Institute of Navigation it is restrained. The tables are as dopey as the calculator instructions. It is a story which deserves a separate article - if I can write it without becoming enraged. Were Dava Sobel to write a sequel to "Longitude" she'd conclude nothing had changed at the RGO.
My S-Table was later published in the Yachtsman's Almanac and then as a separate booklet. A few people have written appreciative letters. Originally I saw the S-Table as a backup to a computer but I came to believe celestial is too complex for even the simplest tabular method to work in an emergency. Now it all belongs to yesteryear yet when I think of the bumbling of those Almanac offices I still get angry.
In 1991 we sold the Merlin business to Wayne Gallivan who had sailed a boat from England to Australia and at the time worked for Boat Books in Sydney. In 1991 the GPS was operating for a few hours a day and it was clear it was doing to the sextant what the motor car did to the horse. Only quicker: when I did my trip up the WA coast in 1995 (see sailing articles), everyone had a GPS. Most people had a Merlin but no one used it. Wayne prosecuted his business for a few years then went back to Boat Books.
There are still people who want to do sextant navigation. My unusual surname makes me easy to find on the internet and I still (2018) get people contacting me to ask to reprogram their Merlin. Usually it's a Merlin II but occasionally someone has an original Merlin and I direct them to the published program.
If you need a Merlin II reprogrammed email
dimitrios@bogiatzoules.de
unless you are within Australia, in which case email me.