Welcome to the NavList Message Boards.

NavList:

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

Compose Your Message

Message:αβγ
Message:abc
Add Images & Files
    Name or NavList Code:
    Email:
       
    Reply
    Re: 'pacing' for boat speed
    From: Hewitt Schlereth
    Date: 2011 Apr 14, 09:38 -0400
    Before electronic instruments were around (early '60s) I sailed on a 73' experiment (early aluminum) and our method was to carry a .22 rifle to the bow and fire a shot into the water. The bullet made a circular splotch of foam the size of a dinner plate. Hearing the shot, a guy at  the stern would start a stopwatch and get the time when the splotch passed the transom. We kept a table of time/speed taped to the bulkhead at the nav station.

    Hewitt

    On Thu, Apr 14, 2011 at 5:39 AM, Paul Werner <paul.werner@comhem.se> wrote:

    apacherunner wrote: "�finding boat speed by counting the time it takes a piece of flotsam to move along the hull."

    I know that as the "spitlog". I think moist snuff was preferred as "instrument".
    It is very easy to calculate and use in the metric system.
    1kn = 1nm / 1hour = 1852m / 3600s = 0,51 m/s ≈ 0,5 m/s.
    Thus for a boat: Speed (kn) = 2*Length (m) / Time (s).
    For my boat, 10m, I divide 20 with time in seconds.
    It can't be used on short high-speed boats.

    Paul Werner

    ----------------------------------------------------------------
    NavList message boards and member settings: www.fer3.com/NavList
    Members may optionally receive posts by email.
    To cancel email delivery, send a message to NoMail[at]fer3.com
    ----------------------------------------------------------------


       
    Reply
    Browse Files

    Drop Files

    NavList

    What is NavList?

    Get a NavList ID Code

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

    A NavList ID Code guarantees your identity in NavList posts and allows faster posting of messages.

    Retrieve a NavList ID Code

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

    Email Settings

    NavList ID Code:

    Custom Index

    Subject:
    Author:
    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