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    Re: Taffrail log and an alternative
    From: Trevor Kenchington
    Date: 2002 Jun 22, 10:41 -0300

    Many thanks to Bill Noyce and Arthur Pearson for their suggested
    solutions to the non-electronic log problem. I'd still like an
    instrument that would record distance run rather than instantaneous
    speed, without needing batteries or an LCD. Still, I might have to force
    myself to compromise on one or the other feature!
    As to Arthur's suggestion:
    > For bay crossings in the fog of Maine and Nova Scotia, a simple 30 foot
    > chip log allows one to measure speed often enough and accurately enough
    > to keep an accurate DR for several hours. Simply tie a bit of wood
    > (weighted on one edge to be traditional and to minimize wind drift) on a
    > length of light line, drop the chip overboard and time the number of
    > seconds it takes for 30 feet of line to run out.  Divide 18 by the
    > number of seconds to get nautical miles per hour, so 6 seconds indicates
    > 3 knots. I measure speed and plot a DR every 15 minutes. Any inaccuracy
    > in speed measurement is less important that whatever allowance one makes
    > for current and lee way. This is all I have had on dozens of trips
    > Downeast and back in Maine and combined with a good ear and a good nose
    > you should be fine (keep the engine off so you can hear surf, gulls,
    > barking dogs, etc.).
    Heaving a chip log is an attractive alternative but a bit awkward if
    single-handed or with a crew that does not share a passion for such
    eccentricities. If reduced to that level of technology, why not go one
    step further and use a Dutchman's log?
    Trevor Kenchington
    Trevor J. Kenchington PhD                         Gadus@iStar.ca
    Gadus Associates,                                 Office(902) 889-9250
    R.R.#1, Musquodoboit Harbour,                     Fax   (902) 889-9251
    Nova Scotia  B0J 2L0, CANADA                      Home  (902) 889-3555
                         Science Serving the Fisheries

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