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    Re: Timekeeping in the post-WWV/post-HF world
    From: Francis Upchurch
    Date: 2018 Sep 27, 19:18 +0100

    I have used 4 cheap quartz waterproof watches for years, select 2 that tend to 
    go + and 2 that tend to go -. Store in thermos flask (temperature 
    control)stored in a metal box (faraday's cage). Take average. Usually 
    accurate to within a second per month. Good enough for me. Check when 
    anchored in known position reverse to get time. If the "system" collapses, 
    main issue for me is will the Almanac tables still be published, not the 
    availability of SW time signals. Carry on Frank!( I have a copy of Geoff's 
    long term almanac, so will probably see me out whatever happens.).
    All shall be well!
    Knowing who you are is more important than knowing where you are! (where ever you go, there you are!)
    Local pilotage sufficient for my current sailing. GPS a great back up for my 
    CN fun. Radar a potential life saver. Good crew with good number 1 eyeballs 
    and ears perfect.
    Best wishes.
    -----Original Message-----
    From: NavList@fer3.com [mailto:NavList@fer3.com] On Behalf Of Steve Dunlop
    Sent: 27 September 2018 18:31
    To: francis@pharmout.co.uk
    Subject: [NavList] Re: Timekeeping in the post-WWV/post-HF world
    **From: *Robert VanderPol II <<*Have you looked into Chip Scale Atomic Clocks? 
     Somebody mentioned $1500 but I don't know for sure.  Don't know what the 
    power requirements would be either.>>
    You can buy the devices themselves.  I was unable to find products intended for timekeeping.
    **From: *Peter Monta <>*
    Thank you for the background, which I found insightful.  I'll look around for 
    surplus products.  A problem I have encountered is that OXCOs etc are more 
    readily available as frequency references than as timekeeping products.  
    Building a timekeeping device around a frequency reference is a science 
    project that I am not inclined to pursue.
    **From:* John D. Howard <<*
    *I do not understand the need for super acurate watches.  Any quartz watch 
    will keep time for a month or so with reasonable acuracy.  Unless you plan to 
    be at sea many months without making landfall ( two women and two dogs ? ) 
    than you can check your watch, to the second, using your sextant. You will 
    have paper charts that have lat and long for most places.  With that and your 
    sextant ( and almanac ) do a time sight.  Set your watch or note how far off 
    it is, down to the second.  No radio, internet, or GPS needed. Like Frank 
    said - invert it.  Use cel nav to get the time!>>*
    You are, of course, correct that the necessary accuracy is only that needed to 
    find a reasonably accurate latitude when making landfall at the end of the 
    longest passage in the voyage, presuming that reasonably accurate charts are 
    available for the area from which the passage begins.  Recreational vessels 
    rarely make passages lasting longer than 30 days, so the question becomes 
    whether the error in a cheap quartz watch is acceptable after 30 days.  With 
    a good quality mechanical watch, you could be off by 150 seconds, with a 
    cheap quartz watch, you could be off by 30 seconds.  Maybe that's close 
    enough.  I am a novice, but it seems like 30 seconds of avoidable uncertainty 
    is worth thinking about, at least a litte.
    [plain text auto-generated]
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