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: Why do we ocean navigators defer to 249 when 229 isbetter?
    From: Bruce J. Pennino
    Date: 2014 Sep 1, 22:30 -0400
    I'm unfamiliar with some of the described methods,  but I'm amazed at how fast HO 249 really is. Almost faster than a hand calculator.  But I've recently tried Weems Line of Position 1927, 4th edition with the polar tables; then tried Ho 208.  Weems is quicker  and somehow more logical  than 208 ( for me). And Weems is complete in one thin small book.......could go anywhere with an almanac.



    On Sun, Aug 31, 2014 at 8:06 PM, Lu Abel wrote:

     I believe it is a matter of accuracy -- accuracy of celestial shots vs accuracy of sight reduction -- and convenience.

    229 will give accuracy comparable to doing Law of Cosines with a calculator.   Might be great for the Titanic, where you had a highly stable platform from which to take shots. 

    But if you're on a smaller craft that's bouncing around a lot, getting a shot with even a minute's accuracy (much less a tenth) is difficult.   So what is the value of a high-precision reduction of a sloppy sight?

    On the other hand, 249 gives adequate accuracy with a great deal of convenience and ease.

    Let's also not forget the Nautical Almanac's sight reduction method, although I'd characterize that as having the accuracy of 249 with the convenience of 229 -- in other words, perhaps combining the worst of both.


    From: Bill B  <NoReply_BillB@fer3.com>
    To: luabel{at}ymail.com
    Sent: Sunday, August 31, 2014 4:01 PM
    Subject: [NavList] Re: Why do we ocean navigators defer to 249 when 229 isbetter?

    On 8/31/2014 6:36 PM, Rommel John Miller wrote:
    > Hi there, it has been awhile and I have been out of touch.  But my
    > question is this:  Why are Nautical and Marine Navigators opting to use
    > HO 249 and shunning HO 229?

    I like 229 as well. More bodies and better accuracy.
    Downside is a lot more books to carry.

    My impression is that 249 is much lighter and may sacrifice some
    accuracy, but will get you across any ocean or sea with less hassle.

    View and reply to this message

    View and reply to this message
    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