NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Fw: A little off topic _ Ebb and Flow
From: Frank Reed CT
Date: 2006 Jul 2, 16:49 -0500
Guy wrote:
"Is there a time relationship between High Tide and Max flood and
converserly low tide and max ebb?"
Only for small coves and estuaries. Then the maximum current occurs very
nearly at the middle time between high tide and low tide. At general points on a
coast, there is no relationship, and you can have a strong current before,
at, and after the time of high tide. This counter-intuitive effect happens
because the current is "feeding" the tide at points further "downstream" from
your observation point.
And Bill wrote:
"Timing of tides caused by the sun and moon might be fair game for a layman's
spreadsheet."
Yes, but you need to include over a dozen tidal "harmonics" to get decent
results. I've done something like this for my cell phone web site here:
_www.fer1.com_ (http://www.fer1.com) (it's "scaled" for cell phone viewing but of
course you can view it from any browser). The tidal application only handles a
few locations right now, but it's easy enough to expand it.
-FER
42.0N 87.7W, or 41.4N 72.1W.
www.HistoricalAtlas.com/lunars
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From: Frank Reed CT
Date: 2006 Jul 2, 16:49 -0500
Guy wrote:
"Is there a time relationship between High Tide and Max flood and
converserly low tide and max ebb?"
Only for small coves and estuaries. Then the maximum current occurs very
nearly at the middle time between high tide and low tide. At general points on a
coast, there is no relationship, and you can have a strong current before,
at, and after the time of high tide. This counter-intuitive effect happens
because the current is "feeding" the tide at points further "downstream" from
your observation point.
And Bill wrote:
"Timing of tides caused by the sun and moon might be fair game for a layman's
spreadsheet."
Yes, but you need to include over a dozen tidal "harmonics" to get decent
results. I've done something like this for my cell phone web site here:
_www.fer1.com_ (http://www.fer1.com) (it's "scaled" for cell phone viewing but of
course you can view it from any browser). The tidal application only handles a
few locations right now, but it's easy enough to expand it.
-FER
42.0N 87.7W, or 41.4N 72.1W.
www.HistoricalAtlas.com/lunars
--~--~---------~--~----~------------~-------~--~----~
To post to this group, send email to NavList@fer3.com
To , send email to NavList-@fer3.com
-~----------~----~----~----~------~----~------~--~---
