TWL: Tides
Hi Everyone,
Here is a list for tides anywhere in the world:
Type in the nearest big city in your cruising area and then scroll down
yo the date you need.
Happy Cruising...
Cap't. Fred
49 Defever
'Tortuga"
Go: Yahoo Groups: "Defever-Yacht-Owners"
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<*)))))))><
Hi Everyone,
Here is a list for tides anywhere in the world:
Type in the nearest big city in your cruising area and then scroll down
yo the date you need.
REPLY
Fat lot of good that does. I asked for a local river name and got Australia
instead.
And what can it do for locations in between major cities.
Without the intermediary stations and the offset tables, such tides are not of
much real use.
At least not to my way of thinking.
Arild
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Thursday, October 16, 2003, 9:51:08 PM, Cap't. wrote:
Hi Everyone,
Here is a list for tides anywhere in the world:
Type in the nearest big city in your cruising area and then scroll down
yo the date you need.
Happy Cruising...
It appears that the tide predictions on that site are generated by
xtide - you can get versions of that program to run on many
computers/operating systems:
Dave Flater (http://www.flaterco.com/xtide/) has a tide program called
"Xtide". It was developed under unix/X11, but has been ported to OS/2,
Windows, DOS, Macintosh, and other platforms.
(I'm particularly impressed by the map that site provides to show the
location of Point Atkinson :-) )
--
Peter Bennett, VE7CEI Vancouver, B.C., Canada
GPS and NMEA info: http://vancouver-webpages.com/peter
Vancouver Power Squadron: http://vancouver-webpages.com/van-ps
Peter wrote:
It appears that the tide predictions on that site are generated by
xtide - you can get versions of that program to run on many
computers/operating systems:
snip<<<<
(I'm particularly impressed by the map that site provides to show the
location of Point Atkinson
REPLY
And that is the point I am making. I keyed in Pitt but the instructions
specifically said not to use two words such as adding river so ended up with
Pittwater Australia.
And Point Atkinson is not close to where I want tide information.
I want tide information for Pitt River which is upstream and well away from
Point Atkinson.
Local topography can influence tides to a great extent. Especially in rivers
and estuaries during spring freshets.
Relying on these calculator programs provides a false sense of security.
cheers
Arild
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REPLY
Fat lot of good that does. I asked for a local river name and got
Australia
instead.
Thank your lucky stars you got Australia Arild.
Could have got Austria.
heh heh.
Cheers
Glenn
----- Original Message -----
From: "Arild Jensen" elnav@uniserve.com
Local topography can influence tides to a great extent.
Especially in rivers
and estuaries during spring freshets.
Relying on these calculator programs provides a false sense of
security.
Hi Arild,
I don't believe that Xtide is a calculator program as I understand the
use of that term. I use WXtide (an Xtide port for Windows available as
a free download at http://www.wxtide32.com/ ) and from their
documentation it appears that they use tidal data from the appropriate
hydrographic agency to generate the predictions. IOW: The program
should give the same prediction that would be found in one of those
little tide books or that you might get by calling the hydrographic
office.
WXtide supports tidal and current predictions for reference and
subordinate stations on a more or less worldwide basis*. I just
checked and, just as you say, Pitt River is not listed. I suspect that
is because, (again) as you point out, the interaction between tidal
and river flows creates a system that is too complex for routine
modeling. My guess is that the Canadian government doesn't publish
tidal or current data for that location.
*An interesting note from the WXtide website: Their program no longer
provides predictions for the British Isles. It seems that the
international agreements about this sort of data have undergone some
changes over the past few years that allow individual countries to
declare ownership of tidal data. The guy that wrote/ported WXtide was
notified by the British government that he would have to pay some sort
of recurring fee in order to publish their data in his program!
Predictably yours,
Alex
Cap'n Fred, interesting site, but one correction. I used it and instead of
tides, I got currents!
Bob Peterson
-----Original Message-----
From: Cap't. Fred
Sent: Thursday, October 16, 2003 9:51 PM
To: trawler-world-list@lists.samurai.com
Subject: TWL: Tides
Hi Everyone,
Here is a list for tides anywhere in the world:
Type in the nearest big city in your cruising area and then scroll down
yo the date you need.
Happy Cruising...
Cap't. Fred
I don't believe that Xtide is a calculator program as I understand the
use of that term. I use WXtide (an Xtide port for Windows available as
a free download at http://www.wxtide32.com/ ) and from their
documentation it appears that they use tidal data from the appropriate
hydrographic agency to generate the predictions.
There is also a port to Palm OS called TideTool that runs nicely on
your PDA. I have found it quite useful for off the cuff trip planning
when I am out to dinner with friends and making weekend plans. See
http://www.toolworks.com/bilofsky/tidetool.htm
Ross Fleming ross@renoun.net
Seattle, WA
Hi Arild,
I don't believe that Xtide is a calculator program as I understand the
use of that term.
WXtide supports tidal and current predictions for reference and
subordinate stations on a more or less worldwide basis*. I just
checked and, just as you say, Pitt River is not listed. I suspect that
is because, (again) as you point out, the interaction between tidal
and river flows creates a system that is too complex for routine
modeling. My guess is that the Canadian government doesn't publish
tidal or current data for that location.
REPLY
I noticed that one website has a disclaimer "NOT for NAVIGATION"
Guess that means its okay for route planning but not for when you are actually
there.
Actually Pitt River is one place with a tide gage. Not only that, but this tide
gage is accessible online for real time data. Which is why I tried to get that
station to compare prediction versus fact.
There are many water level gages along the river here, but I have been unable to
find out who operates them or where to access the data. A few are available
online but not all.
This is a new trend in hydrography. The entire St. Lawrence Seaway and Great
Lakes system is wired for depth.
All of the stations can be accessed by phone or internet for a present time
water level reading.
When I was doing surveys back there we would phone the nearest gage for a
recording and annotate our field notes with this information. We were not only
doing water depths but also checking bridge clearances so exact water level
readings was crucial.
The St. Lawrence seaway system is so sophisticated that the commercial ships
equipped with ECDIS can have the real time data radioed to the ship and the
chart system is automatically updated to match the gage readings.
This is essential when the cargo vessels are running with only one meter keel
clearance.
Rainfall and hydro-electric power generation activity can cause marked changes
in water levels that are not predictable by any tide program.
*An interesting note from the WXtide website: Their program no longer
provides predictions for the British Isles. It seems that the
international agreements about this sort of data have undergone some
changes over the past few years that allow individual countries to
declare ownership of tidal data.
REPLY
Regrettably this is part of the new world order. We have moved into the
information age and data is now seen as a commodity to be bought or sold, not
shared freely for the benefit of all.
cheers
Arild
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Hmm, interesting whether you get tides or currents seems to depend on what
city name you enter. Enter www.tides.info, type in San Francisco and tell
me if you get tides, I get currents!
Bob Peterson
-----Original Message-----
From: trawler-world-list-bounces@lists.samurai.com
[mailto:trawler-world-list-bounces@lists.samurai.com]On Behalf Of Bob
Peterson
Sent: Friday, October 17, 2003 8:03 AM
To: Cap't. Fred; trawler-world-list@lists.samurai.com
Subject: TWL: RE: Tides
Cap'n Fred, interesting site, but one correction. I used it and instead of
tides, I got currents!
Bob Peterson
-----Original Message-----
From: Cap't. Fred
Sent: Thursday, October 16, 2003 9:51 PM
To: trawler-world-list@lists.samurai.com
Subject: TWL: Tides
Hi Everyone,
Here is a list for tides anywhere in the world:
Type in the nearest big city in your cruising area and then scroll down
yo the date you need.
Happy Cruising...
Cap't. Fred