Welcome to the NavList Message Boards.


A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding

Compose Your Message

Add Images & Files
    Re: Chip log
    From: Rick Emerson
    Date: 1998 Nov 15, 08:42 EST

    Bob responded to a question I posed on the list about traverse boards
    and whether anyone still uses one.  The description of a chip log is a
    pretty good one.
    S/V One With The Wind, Baba 35
    ------- start of forwarded message (RFC 934 encapsulation) -------
    From: bob-norris{at}XXX.XXX
    To: rick{at}XXX.XXX
    Cc: live-aboard{at}XXX.XXX
    Subject: Re:  Chip log
    Date: Sat, 14 Nov 1998 21:02:23 -0500
    Hi, Rick --
    I think you asked about details on a chip log during the thread on
    traverse boards.  I lost your address, and was waiting for you to chime
    in again.  I remembered Baba 35.
    Consulting my old Sea Scout manual, I find that it's a quadrant of wood,
    weighted on the rounded side so it will float vertically, rounded side
    down.  A bridle, about 6' long in total, connects the lower corners, and
    a tapered wooden plug is seized to the middle of it.  The main length of
    the log line is connected to a hole in the peak, and about 3' along it is
    seized a wooden socket that fits the tapered plug.  With the plug in the
    socket, the chip sits upright, and when streamed stays virtually still in
    the water as the ship moves on.  When the timing is finished, a tug on
    the log line pulls the plug out of the socket, the chip flips, going
    nearly horizontal, and is easily retrieved.
    Quoting:  "The log line is small stuff, similar to the lead line, loosely
    laid flexible untarred hemp being the best.
     "(The line) is got on a stretch, wetted, and marked as follows: The log
    line should be at least 150 fathoms long.  Fifteen fathoms from the chip
    is a piece of red bunting.  This marks the end of the stray line, the
    line allowed to run over while the chip gets settled comfortably in the
    "From this piece of bunting distances are marked off every 47' 3" by a
    piece of fish line seized between the strands of the log line.  Each
    division from the red bunting is marked by knots in the fish line, one,
    two, three, etc. [Ergo, "knots" -- Bob]  These main divisions of the line
    are each further subdivided into 5 equal parts by bits of white bunting,
    indicating each 2/10 of a knot.  Single tenths are arrived at by
    "The line, being marked, is wound on a large reel with handles.
    "The other instrument, and a very important one, is the log glass, and
    old-fashioned sand glass filled and regulated at the chronometer, to run
    out in 28 seconds.
    "Then we have the proportion...:  Twenty-eight seconds is to one hour, as
    47 feet, 3 inches is to one knot; or 6,080 feet (the sea mile, or length
    of an average minute of arc on a meridian of the earth."
    So:   28 sec. / 3600 sec. = 47.25 feet / 6080 feet  = 1 knot (run out
    when the log glass empties)
    The more feet run out, the more knots and white buntings show up, and
    obviously the faster you're going.  When your helper calls "mark" as the
    sand stops, grab the log line and count the knots and tenths.  If the
    plug hasn't pulled out yet, yank the line and reel it in.
    Actually, get your apprentice to reel it in while you go put the peg in
    the traverse board.  Executive Privilege, you know, deserved by your
    Superior Knowledge (which keeps you out of Situations that demand your
    Superior Skill, etc.).
    Hope this diverted your mind from contemplating the sorry state of the
    world for a little bit :)
    You might forward this to the Navigation list.  I don't know the address.
    S/V "High Hopes"
    - -- "Gentlemen never sail to weather."
    S/V "High Hopes"
    ------- end -------
    =-=  TO UNSUBSCRIBE, send this message to majordomo{at}XXX.XXX:     =-=
    =-=      unsubscribe navigation                                         =-=

    Browse Files

    Drop Files


    What is NavList?

    Join NavList

    (please, no nicknames or handles)
    Do you want to receive all group messages by email?
    Yes No

    You can also join by posting. Your first on-topic post automatically makes you a member.

    Posting Code

    Enter the email address associated with your NavList messages. Your posting code will be emailed to you immediately.

    Email Settings

    Posting Code:

    Custom Index

    Start date: (yyyymm dd)
    End date: (yyyymm dd)

    Visit this site
    Visit this site
    Visit this site
    Visit this site
    Visit this site
    Visit this site