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: leeway
    From: Buck Godwin
    Date: 2001 Dec 06, 7:45 PM

    Ross Garrett wrote that leeway is proportional to the sine of the heel
    angle and inversely to the square of the boat speed.  He cites a
    proportionality constant of 464 based on model tests of for a
    particular 12.2 meter boat when using leeway in degrees and boat speed
    in knots.  In section 3.5.3 he presents a graph that shows good
    agreement between the model test data of the actual leeway and the
    leeway calculated from full-scale trial data.  He recommends the
    proper constant be determined for each boat from trials.  It is fairly
    independent of sail area, unless heavily reefed.  I believe the
    constant would depend on the hull bottom condition.
    Rather than measure leeway by your wake, steer a steady course from a
    floating marker dropped overboard and take a bearing on that marker.
    Leeway is taken as the difference in the relative bearing and 180
    degrees.  Don't use a tethered buoy, unless there is no current.
    Measure heel angle and boat speed as well, to determine your boat's
    constant of proportionality.
    I am quoting from "The Symmetry of Sailing" by Ross Garrett, Adlard
    Coles Limited, 1987
    Buck Godwin
    > -- --from Ocean Navigator #45 p. 72
    >Is an approximation of leeway.
    >Steve Tripp

    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