In 1983, Bob Goethe moved to Japan for two years and purchased a 13 foot Yamaha dinghy. He was relatively new to sailing at the time, and had several nautical skills items on his learning to-do list. For instance, he wanted to learn how to reef well, so he had Yamaha put reefing points in his dinghy mainsail...a request his Yamaha salesman found quirky, but was happy to fulfill. He also wanted to learn how to sail without a rudder, by sail trim alone.
Yet another of the things he wanted to learn was how to
use a sextant. The Yamaha salesman had clearly never
before sold a sextant to a dinghy customer, but all the
same acted as the middle man to help Bob acquire a
Tamaya "Venus" sextant. Only later did Bob learn
that Tamaya sextants had a world-wide reputation for
excellence.
Bob would take his sextant out while he was singlehanding his dinghy off the coast of Kyushu Island, and take sun sights. In the dinghy there was no room to carry a nautical almanac and sight reduction tables, of course. So Bob would record his times/altitudes in a notebook, and then when he got home in the evenings, he would do the work of sight reduction and plotting. On a good day, Bob could fix his position to within a mile or two. On a bad day, he would plot his position in the middle of the live volcano some 60 miles south of Beppu Bay.
As Bob chartered sailboats over the next 30 years, he brought his sextant along from time to time to help him continue to sharpen his celestial skills – usually in the Gulf Islands of BC, but more recently in the Caribbean, and once on a clipper-ship cruise in the Aegean.
In the last 5 or 6 years Bob has invested more heavily in learning the theory behind celestial navigation, working through the equations of spherical geometry, and digesting the 2002 edition of Bowditch, then (to get a better sense of how techniques have varied over time) the 1905 edition of Norie and the 1908 edition of Lecky.
Lecky wrote with a sparkling wit. If you are the kind of person who whiles away the time during an Alberta blizzard by reading books about the sea, Lecky could be for you. In its day, this volume was influential enough that a copy was kept in the navigation station on Queen Victoria's yacht. A facsimile edition has recently been published, and you can buy it here.
In the course of his study of methods of statistical averaging of
sights – so that you can identify and throw out "bad sights" – Bob
found hints that the 1977 edition of Bowditch might be
a good bit better in its treatment of celestial than anything else at his disposal. Bob was able to pick up a pristine copy of the 1977
edition of Bowditch (volume 1, together with its sister, volume
2...published, oddly enough, two years earlier – in 1975) on
eBay, and he has
worked his way through that edition from cover to cover as
well.
As it turns out, the 1977 edition was indeed the very peak of Bowditch's treatment of celestial. By the time the 1995 edition came out, GPS navigation was practical. The editors of Bowditch, in the desire to keep their work from becoming unwieldy, decided they could consolidate their two volumes into one by taking out some of the celestial navigation material.
That is to say, the current edition of Bowditch still tells you everything you need to DO to navigate by the sun and stars. It just doesn't take the same time it did in 1977 to tell you WHY you do those things.
In the course of his studies, Bob has enjoyed doing sights of stars, planets, the sun and the moon from his house, using an artificial horizon, and has fixed the location of his living room some hundreds of times.
Last
summer, as Bob was getting his Sail Canada Offshore Certification by
cruising from Hawaii to Victoria, he had the opportunity to serve as the
vessel navigator.
Bob,
in the red shirt, with Jim Humphries, Commodore of
the Alberta Offshore Sailing Association, during
last summer's cruise from Hawaii to Victoria. This was a golden chance to learn a system that used the HF radio, AIS, radar, and GPS...all tied together by a
Windows 8.1 PC that integrated downloaded weather GRIB
files with performance characteristics of his individual
boat to suggest an optimal, hour-by-hour course for the
next day and a half.
All the while he was having this superb learning experience, Bob was maintaining a parallel set of position fixes using his trusty Tamaya sextant — still as accurate as the day it was purchased — primarily for fun, but also because Bob is, so to speak, into wearing both suspenders AND a belt. He wanted an independent, redundant navigation system as a backup in case something unexpected occurred with the electronics array. (Is this true? Can you actually plan for the unexpected?).
It was while on board this trip with Jim Humphries, the commodore of the AOSA, that the idea of teaching celestial nav in Edmonton floated to the surface.
Bob spent the autumn of 2014 working with the planetarium at the Telus World of Science, to see if it would be a suitable venue for a course. While the planetarium people sought to be helpful, Bob discovered that the view of the stars under the dome only resembled the stars actually in the night sky.
The actual stars are effectively at an infinite distance from us...but under the dome of a planetarium, you may only be 30 feet away from one star, while being 80 feet away from another.
When a 2° discrepancy in the apparent height of a star translates into a positional error of 120 nautical miles, these differences matter quite a bit. The issue of "dome parallax" was a tough nut to crack...even involving one day bringing a laser range finder to the planetarium to get a better idea of the precise shape of the dome (which over the decades has slumped several centimetres at its peak).
As it turned out, the laser was never even taken from its case. A sextant is a precision optical instrument, capable of measuring 1/600th of a degree...and the verdict was clear as Bob looked through his: any star we used, in any given square inch of the dome, would require a unique correction to make its position resemble that of the equivalent actual star.
In the end, the planetarium idea was just not feasible.
But with the new year came the willingness of Phil Sutton to loan
three of his sextants for educational
purposes, plus the enthusiasm of the Alberta Offshore Sailing
Association and the Edmonton Yacht Club, who both entered into a
partnership with Bob to teach celestial navigation here in the
prairies. All the pieces for 2015's course fell into place
by early March!
One of the items Bob still has on his navigational-to-do list is to use a 3D printer to create the "Mark 1 Navigator's Slide Rule", to help yachtsmen calculate great circle distances and courses while at sea. 3-D printers large enough to print a 10" rule, while available in the wide world now, are not available to Bob, in Edmonton, quite yet.
Bob has had business ideas that have flourished, and business ideas that have crashed and burned. Manufacturing a slide rule 40 years after the electronic calculator wiped out the entire slide-rule market is probably a project that is destined to crash and burn. But maybe with the ability to "mass produce" items one at a time, Bob will be able to identify the 5 other people in the whole world who would find such a product intriguing. Then all 6 of them can go sailing together to the South Pacific, navigating by old and new together: a slide rule on the chart table right next to the GPS.
As for what Bob does when he is not dreaming of the sea, click here to go to the upper level of this web site, and see what Bob's business involvements are.