NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: About time - Antarctica
From: Lu Abel
Date: 2012 Mar 5, 11:29 -0800
From: Lu Abel
Date: 2012 Mar 5, 11:29 -0800
Good question. Or, for that matter, when they say the Marianas Trench is 35,000 feet deep, how did they measure that? Too far, I would presume, for sonar.
Lu
From: Bruce Pennino <bpennino.ce@charter.net>
To: NavList@fer3.com
Sent: Monday, March 5, 2012 10:49 AM
Subject: [NavList] Re: About time - Antarctica
They were measuring 1000s of feet of depth. How could they "feel" when the object touched or bounced off the bottom?
Bruce J. Pennino, P.E.----- Original Message -----From: Gary LaPookTo: NavList@fer3.comSent: Monday, March 05, 2012 12:27 PMSubject: [NavList] Re: About time - Antarctica
Very much like using a hand lead line except it was a much heavier weight on a long wire which was on a motorized reel. This device was called a "deep sea lead."
gl
--- On Mon, 3/5/12, Bruce Pennino <bpennino.ce@charter.net> wrote:
From: Bruce Pennino <bpennino.ce@charter.net>
Subject: [NavList] About time - Antarctica
To: NavList@fer3.com
Date: Monday, March 5, 2012, 7:50 AM
Just finished reading The Storied Ice by Joan Boothe. A very good overview book about all major explorations of Antarctica; many references.Anyway, Antarctica explorers had a longitude problem. In 1926-27 the Discovery "was the first vessel in these waters capable of receiving Greenwich time signals directly, and her men used the signals to check longitudinal positions on the maps." Only Deception Island was properly located.Also,as the early explorers headed south ,they measured water depth for various reasons. How did they measure depths of several thousand feet with a drifting ship, angle of cable, flexibility(springiness)?Boothe gives a brief overview of Cook's explorations....she says he was an extraordinary man.
Bruce Pennino