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: New compact backup CELNAV system
    From: Hewitt Schlereth
    Date: 2009 Mar 19, 15:00 -0400

    At the risk of shameless self-promotion, you might want to take a look
    at my Sight Reduction Tables for Small Boat Navigation. It's 229 cut
    down to one 7"X9"X1" volume. The reduction of 229 was done by 1)
    limiting declinations to 29N-29S in the usual one degree increments;
    2) limiting latitudes to those between Cape Farewell Greenland and
    Cape Horn (58N-58S) but in 2-degree increments; 3) likewise tabulating
    LHA in two-degree steps; 4) using the 249 interpolation table for
    declination increments.
    
    What this means is your AP must lie on an even degree of latitude and
    your assumed Longitude must give you an even degree of LHA. (By even,
    I mean divisible by two.)
    
    So, at the price of sometimes having long intercepts, you have an an
    inspection table, which is what most navigator's learn with. With
    SRTSBN there's nothing new to learn.
    
    -Hewitt
    
    PS I don't have books to sell. They've been out of print for quite a
    while. The copy I have was bought through Amazon Marketplace. -H
    
    On 3/19/09, Anabasis  wrote:
    >
    >  > Though in this day and age emergency navigation seems to mean drifting
    >  > in life raft without any control and praying that coast guard got your
    >  > mayday or EPIRB signal and will pick you up before water runs out.
    >  > Navigation without mobility is quite useless.
    >  >
    >  > Martin
    >
    >
    > For a merchant ship I would agree with this Martin as liferafts are
    >  completely uncontrolable, and most lifeboats have only 24 hours of
    >  fuel and oars (sails are extremely rare on L/B's these days) and
    >  therefore you don't "go anywhere" but rather flip on the EPRIB and
    >  SART and await the proverbial cavalry.  However, another "emergency"
    >  navigation system that would require actual navigation is in a
    >  sailboat where a wave or other failure wiped out all of the
    >  electronics (except a watch which should survive) mid voyage and you
    >  are "stuck" with celestial navigation.  Instead of packing all sorts
    >  of volumes of sight reduction tables in your limited space, you might
    >  want to have the various tools described in this thread.
    >
    >  My 2 cents,
    >
    >  Jeremy
    >
    > >
    >
    
    --~--~---------~--~----~------------~-------~--~----~
    Navigation List archive: www.fer3.com/arc
    To post, email NavList@fer3.com
    To unsubscribe, email NavList-unsubscribe@fer3.com
    -~----------~----~----~----~------~----~------~--~---
    
    

       
    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