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    Re: Navigate using seafloor data
    From: Jackson McDonald
    Date: 2017 Sep 15, 13:22 -0700

    This discussion prompted me to dig through my modest navigation library for "Bathymetric Navigation and Charting," Philip M. Cohen, United States Naval Institute Series in Oceanography (1970),138 pages.  I purchased this slim book on eBay a couple of years ago but didn't focus on it until today.

    Please see the attached pdf of the book's cover and table of contents.

    Chapter V  - Determination and Recovery of Position seems pertinent to this discussion.

    I have not scanned the chapter, which may or may not still be copyright protected.  

    It begins, "It is important to reiterate the distinction between bathymetric positional requirements for general navigation and for accurate locations."  The author states that the techniques for achieving accurate locations are sufficient for navigation... "greater accuracy is of marginal use for navigation."  The author then mentions a need for bathymetric charting of "greater areas of the world and for better degrees of reliability."  He adds, "Certainly it can be expected that the major difficulties in providing dependable long-range navigation will soon be solved.  However, very little ship time is lost even now because of navigational uncertainly; on a quantitative basis more delay is caused by weather conditoins such as fog or heavy seas."

    Chapter V then addresses the following topics and subtopics:   

    Gravity observations

    Positioning and recovery techniques

    Recognition techniques

    Positioning by canyon

    Positioning by seamount

    Display effects of wide sound cone

    Precedural techniques

    Profile-matching technique

    Contour advancement

    Line-of-soundings technique

    Side-echo technique

    Computer application to surveying.

    This book is concisely written, the prose is accessible to the layman, and the graphics are clear and easy to understand.  I presume there have been significant advancements in bathymetric charting and navigation since this book was published 47 years ago, but the many of fundamentals probably remain valid.

    I would be pleased to scan and post Chapter V, but only if NavList can allay my concern about copyright.  


    28° 21.11’ N

    80° 43.45’ W




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