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: Sperm whale buoyancy.
    From: Henry Halboth
    Date: 2007 Mar 25, 21:48 -0500

    To all interested,
    Perhaps we should clarify just what the bends and nitrogen narcosis are, and
    how they separately affect the diver.
    Many years ago, Dr. Haldane, an English physician, established that if the
    human body contained dissolved gas at a pressure greater than twice the
    outside pressure, bubbles would form. It is the formation of these bubbles
    and their entrapment in the body tissues that cause the so called bends, or
    more technically "decompression sickness". The most practical method of
    bringing a diver to the surface, from depths of 60 feet and grteater, in
    order to prevent the formation of bubbles was originally "staged
    decompression", or stopping  the ascent at regular intervals for a time
    sufficient to allow gas to escape from the blood stream without the
    formation of bubbles. Dr. Haldane's work lead to the first successful
    decompression tables to the benefit of divers and caisson workers generally,
    and more recent developments, i.e., surface decompression, mixed gases,
    etc., have lead to modifications that there is no point in discussing hear.
    The pathophysiology of the "bends" is based on the breathing of gases under
    pressure and their subsequent too rapid release, leading to the formation of
    systemic bubbles which seem to concentrate primarily in the joints, and
    which may also lead to massive pulmonary embolism and rapid demise.
    Nitrogen narcosis is an intoxication occasioned by the breathing of nitrogen
    and argon, both constuients of atmospheric air, at the increased partial
    pressure encountered when atmospheric air is compressed at great depths. It
    affects the sensory perception and muscular coordination of a diver working
    at great depths on compressed air. The solution to this problem was found in
    the employment of helium and other mixed gases in deep diving operations.
    Just as some people can consume greater amounts of alcoholic beverages than
    others without ill effect, the affects of nitrogen and argon are not as
    predictable as the onset of the bends.
    George's comments regarding the compressibility of the body are most
    probably true, however, to the best of my knowledge, not presently of
    practical consequence or experimentally quantified.
    Although of considerable interest generally, and subject to considerable
    elaboration, my comments are outside the scope of this List and I have
    chosen to go no further.
    ----- Original Message -----
    From: "Michael Dorl" 
    Sent: Sunday, March 25, 2007 3:00 PM
    Subject: [NavList 2478] Re: Sperm whale buoyancy.
    > My uninformed two cents worth...
    > I wonder if the bends and nitrogen narcosis for divers with large air
    > supplies (either hard hat or aqua lung) are not caused by not caused by
    > large volume of air they are exposed to under high pressure over
    > time.  Stated another way, if all of the air in an animals lungs (one
    > volume) were to go into solution in the blood would that be enough to
    > narcosis and bends?   Or would it require many lungs full?
    > >
    To post to this group, send email to NavList@fer3.com
    To unsubscribe, send email to NavList-unsubscribe@fer3.com

    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