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: Nocturnal used to find time if HW.
    From: Hewitt Schlereth
    Date: 2011 Dec 27, 21:08 -0800
    Now that I've moved to the West Coast, I may have a chance to check it out here.  Hewitt 

    Sent from my iPad

    On Dec 27, 2011, at 2:55 PM, Apache Runner <apacherunner@gmail.com> wrote:

    With the diurnal tides, that works pretty well.   On the west coast, say, in Puget Sound, I'm not sure it works so well with semi-diurnal tides.  I tried to construct a similar chart for Puget Sound and found it wanting. 

    One of my favorite local examples are the tides at Newport and the tides at Boston.    High tide in Boston is pretty close to the lunar transit, while low tide in Newport is close to the lunar transit. 

    The tidal system for Nantucket Sound and Long Island Sound is curious.  The flood comes in from the south and floods both east into Nantucket Sound and west into LI Sound.    There's even a curiosity where at the southern tip of Monomoy Island, the flood tide actually flows east into the Atlantic, which seems a bit bizarre at first blush. 

    Also, with a lot of constrictions in LI and Nantucket Sound, some decent currents are created. 

    On Tue, Dec 27, 2011 at 5:16 PM, Hewitt <hhew36@gmail.com> wrote:
    My 1939 Bowdich has a table of luni-tidal intervals for many ports around the world. I found it worked real well for the US East Coast, and included it in my coastal nav book.  Hewitt 

    Sent from my iPad

    On Dec 27, 2011, at 6:54 AM, Apache Runner <apacherunner@gmail.com> wrote:

    The was a pretty common way of finding tides.   Almanacs would describe the lag or advance between MP of the moon and the tide.   In some cases, ports would be clustered by the location of the moon (NW, SW, SE, E etc) when high tide occurred, and then the timing was given in terms of days after the new moon. 

    Some students in my class constructed replicas of nocturnals and tested them out.   

    On Tue, Dec 27, 2011 at 6:18 AM, Keith Lindsay <kw.r.lindsay@gmail.com> wrote:

    This nocturnal was made by Hunfry Cole of London in about 1575. To find the time of HW you also have to know the 'Establishment of the Port'. References in this paper have a table of lunitidal intervals.

    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

    Keeping up with the grind

    Keeping up with the grind
    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