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: sextant without paper charts
    From: Bruce Hamilton
    Date: 2008 Nov 13, 13:57 -0800
    I am very happy to see that Jeremy uses methods other than GPS for his fixes, and I hope that that is the general trend among merchant officers these days.  The fifteen minutes might have been in close quarters situation since they spend a lot of time in skinny fjords with less than a mile of water between the ship and the hard stuff. At the time he told me this GPS chart plotters were quite new and he said there were times when the mates were relying on the plotter a little too heavily.  I'll ask what his standard practice is. I'll also get some details about how high he was in the Arctic and what sort of GPS errors he was getting up there.
     
    My first captain when I was a first year cadet used to give me the finger test when ever he popped up on the bridge.  I had to go to the chart and point to where I thought we were and where any traffic was and the names of any prominent points of land or lights in the area.  It really made the concept of situational awarness quite clear.
     
    Canadian merchant officers who work the great lakes get really used to working in really close quarters all the time without pilots or tugs. A captain of mine used to moonlight as a St. Lawrence  and Great Lakes pilot and he had great stories about how some of the bridge crews of the salties would react to some of the tight situations when seeing them for the first time. In a way it was nice to get out of the river and have a bit of  distance between us and the coast. As a nav cadet, I used to spend a good deal of time at the helm, and the captain would tell me things like "keep it in the middle" then leave me to sweat my way through a narrow channel. If I started to look too stressed he would give some helm commands, but it was a great way to learn ship handling.
     
    Thanks for the fix information Jeremy. It is great to see where you are in the world.
     
    Happiness is a warm chart.
     
    Bruce wrote:
     
    "Without having to plot fixes every 15 minutes there is a tendency for
    bridge crew to rely solely on the information on the screen and not be
    aware of where they actually are.  I have a friend who is a merchant
    captain who still has standing orders for the mates plot a position on
    the paper chart every 15 minutes by some method other than GPS.   If you
    are in within a few miles of land, then then this is really essential in
    a big ship."
     
    In my ten years out here I've never seen such orders.  My captain dictates a position ever 30 minutes in "inland waters" which to him means bodies of water like the East China Sea.  While I believe it is absolutely prudent to fix position using multiple inputs (I am quite certain mates use radar range and/or bearings to fulfill this particular standing order), mates must also be very mindful of vessel traffic.  With a modern merchant bridge team consisting of a AB/helmsman and a Mate on watch, it can be very distracting shooting visual bearings and radar information then plotting them on a chart.  It is VERY easy to lose situational awareness and run over a fishing boat or come into close quarters with another vessel if your head is buried in the chart plotting LOP's or running calculations instead of looking out the window to see what is going on.
     
    My point is, while it is very important to know your position, it is equally important to be aware of other hazards to navigation.  There must be balance to manage the bridge correctly, and the PROPER use of electronic navigation devices such as GPS should augment and verify what visual, audio, and/or radar information is telling you about where your vessel is, and what other vessels may be doing.
     
    For my part, I routinely use visual and radar information both in navigation (turn bearings, parallel index lines, etc) and for traffic avoidance (bearing drift of targets, ARPA).  I certainly check my GPS to make sure I am close to my track line, and verify that information when I can.  I am very comfortable with my position when i am watch because i take into due regard all information that I can acquire from my bridge equipment and my own senses.  I even shoot stars in the open ocean to verify position, but you knew that already ;-) I certainly do not rely on GPS alone in navigation the 650 ft long ship I stand watch on.
     
    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