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
    or...
       
    Reply
    Re: 'pacing' for boat speed
    From: Jeremy C
    Date: 2011 Apr 14, 10:08 -0400
    This technique is known to me.  The old timers tell me that if the Doppler log died and they had no traditional log, jetsam was released on the bow or bridge and the elapsed time to the stern was used to calculate the speed through the water.
     
    Given a ship is 400-600 foot long, you can be fairly confident with your speed determination can be decent with a stopwatch.
     
    When your are talking about a 30-60 foot yacht, the speed accuracy diminished due to the lack of time precision.
     
    Now of course we have GPS speeds as well as the log, so if the log is dead, you just go with GPS.  Frankly, the speed log on my ship has either not worked, or been wildly inaccurate for years.
     
    JCA
     
    In a message dated 4/13/2011 6:43:41 P.M. Eastern Daylight Time, apacherunner---.com writes:


    Here's a question about the historical practice of reckoning a boat's speed on the water.   The use of log-lines is pretty much a given.

    In  historical accounts, of varying accuracy, I've read about one technique called 'pacing', where the mariner drops some garbage in at the hull and walks toward the stern, keeping abreast of the garbage.   I've also read an assertion by Samuel Eliot Morrison that Magellan's captain has a  quote that corresponds to finding boat speed by counting the time it takes a piece of flotsam to move along the hull.

    I've also heard that it's more of an intuitive feel.

    I'm a sea kayaker and not a sailor, so I estimate the speed from my paddling and the wind conditions - I'd probably vote for the more intuitive school if you were to ask me, but I'm curious whether anyone in the past practiced some technique using the timing of flotsam passing by.


       
    Reply
    Browse Files

    Drop Files

    NavList

    What is NavList?

    Join NavList

    Name:
    (please, no nicknames or handles)
    Email:
    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:

    Email Settings

    Posting 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