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    Re: Shortwave radio and the evolution of celestial navigation
    From: Bob Goethe
    Date: 2018 Jun 13, 01:53 -0700

    Bob Goethe, suggesting an addition to Ed's chronology, wrote a few days ago:
    "I think the combination of transistor shortwave radios, station WWV, and Seiko's quartz watch is what finally allowed the St. Hilaire intercept-method to come into its own among small boat sailors."

    This is an interesting hypothesis. Bob, could you elaborate on your thinking here? Can you think of any evidence that would support this model? 

     


     

    I would be happy to unpack my thoughts on this.  Let me share vignettes from my memories, then suggest some possible implications.

    Our family got its first TV in the mid 1950s, and then replaced it with another around 1960 or so.  Both of those TVs used vacuum tubes, and both went on the fritz at fairly regular intervals.  When they did, my dad would remove the back of the TV, pull all of the tubes, put them in a paper bag, and then – with me in tow – would go down to the store to test/replace the tubes.

    From my perspective in 2018, I am thinking that those failures were driven by both thermal fatigue that caused filaments to break, and by less-than-perfect vacuums during manufacture.

    In any case, what I remember of the tube testers is that they had with a vast number of sockets on them.  Dad would check the serial number on each tube, and compare it to a booklet or card that indicated the proper socket to test each tube.

    I got my first battery-powered transistor AM radio – a Sony that was around the size of two paperback books – around 1960 or so. 

    I got a Hallicrafters shortwave radio receiver in 1968, and by 1969 had strung an antenna up to the roof of the house.  I can remember listening to Moscow, the Voice of America, Radio Havana, station HCJB from Quito, Equador...and WWV from Fort Collins, Colorado.  It was then I became a time-junkie, and would reset my wrist watch on a daily basis after listening to WWV.

    My memory of a half-century ago is a little fuzzy, but I am pretty sure my mechanical, wind-up watches drifted by 15 to 40 seconds a day.  “Rating” such a watch was a matter of sorting out hourly changes, rather than daily changes.


     

    Now, Lecky in his Wrinkles in Practical Navigation was an evangelist for great circle sailing, which leads me to believe that by 1900 most or all commercial cargo and naval vessels had marine chronometers aboard.

    Joshua Slocum, famously, did not.  And I am betting that as yachting broadened into the middle class, many small boat sailors 60 years after Slocum did not have a chronometer aboard either.

    Based on what I saw of vacuum tube technology in our televisions, I am guessing that widespread use of tube-based marine radios would be confined to vessels large enough to carry some sort of tube-tester as well as an inventory of replacement tubes.  In a seagoing vessel, there would not only be thermal fatigue in the filaments of the tubes, but mechanical fatigue from the banging around in the waves.

    My impression is that time signals had been broadcast from many countries for a number of decades.  But in the USA, WWV was established in Colorado because its predecessor in Maryland could not reach all of continental United States. 

    So I am guessing that most time signals prior to the mid-60s were relatively limited in the area they covered.  Small boat sailors going offshore would need to be capable of navigating without time signals, even if they did have a radio that could receive them.

    And if you were limited to the Timex on your wrist (“The watch took a licking, but it’s still ticking”) or even a higher quality Longines that was properly set when you left Halifax, you could easily be 2 minutes out before you made it to Bermuda.  Bermuda is low enough that a 2 minute error in your navigational timepiece could lead you to miss Bermuda, below your horizon, altogether.

    I am guessing that many small boat sailors used Slocum’s method:  Polaris and noon-sun sights for latitude, and dead reckoning for longitude.  The goal would have been to get to get on the latitude of the destination and finish up the last couple of hundred miles by sailing down that line of latitude.

    My supposition is that when finally small boat sailors DID find solid state shortwaves affordable, and/or purchased a quartz watch, and acquired a copy of Pub. 249, the St. Hilaire method did indeed finally become practical for the small boat sailor in a way that it never had been before.

    As for “What made bluewater sailing more accessible...?” I would say that it was both the navigational innovations related to the availability of accurate time, plus the use of fiberglass in boat manufacture.  Fiberglass brought the cost of boatbuilding as well as ongoing maintenance down into the price range of the middle class.

    Bob

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