On Thu, 1 Sep 2005 18:51:00 +0800, Robert Delfs <[log in to unmask]>
wrote:

>Getting the tide right is important for some kinds of diving. At
>seamounts and other exposed sites, there may only be a narrow window
>when the dive can be safely attempted.

Very true.  Also true of many tidal dive locations that are not
seamounts, in your home playground Bali, as well as in Palau,
The Tuamotu groups of Islands in French Polynesia.


>I've
>long been looking for a good tide prediction program with a database
>broad enough to cover some of the sites I dive here in southeast Asia.
>Now I've found it.

Sounds like one who has found the Rosetta Stone, whatever that is. :-)
But I am a born skeptic.

On a more serious vein, from your description, there are very good
scientific reasons why this tide prediction program s akin to
stock prediction programs.


>For me, there are four stations around Bali (one at Benoa, near where I
>live, another at Buleleng in North Bali (not far from Tulamben), two
>more in the straits between Java and northwest Bali (near Menjangan
>Island), and two more on western Lombok, making it possible to combine
>with the Benoa data to get reasonable times for Nusa Penida.

The SMALLER the region, the better.  The question is HOW do you
get current (as in present) data to adjust the long term (Almanac
type of prediction years ahead -- which this tide software seems
to be).

Here's a dead giveaway:

*>  Predicts tides from 1970 through 2037.

Why would anyone want to "predict" tides in the past?  :-)  Why limited
to 2037 if the prediction has some REAL DATA backing?  No wonder no
program even detected the latest Tsunami -- their only reliable
prediction was when they saw elephants start climbing trees. :-)

>
>WXTide32, a free (Windows) program by Mike Hopper, is based on XTide, a
>UNIX program written by Dave Flater. The program is very easy to
>install and use. It covers more than 9,500 tide stations worldwide, and
>can present tidal data in a variety of formats. For North America,
>there are also 100+ tidal current stations (don't ask me how this part
>of the program works - I don't know.) The current version of WXTide
>(4.2) was released in July, supports World Vector Shoreline (WVS) map
>files, which must be downloaded and installed separately. These are
>different from the NOAA WVS files, but are also free. The full set of
>WVS map data files provide zoom factors from 1:43,000,000 to better
>than 1:250,000, which means you may be able to zoom right in to your
>favorite dive site.

Sounds like a good toy.


>Few things in life that are really good are free, but this is.

Nah!  And this is no exception!  It even wisely has a disclaimer
and warning to those who think they've found a good free lunch:

#>  Do not rely on the output of this program for decisions
#>  that can result in harm to any person or property.

>WXTide32 :
>   http://www.wxtide32.com/index.html

>Enjoy
>
>Frogfish (Robert Delfs)


Thanks Frogfish for the info.  It is interesting and it even sounds
promising.  But the GIVEAWAY is a very noble red flag waved by the
giver:  Let the Buyer (of the Free Gift) Beware!

Lots of governmental agencies and private industries spends
billions of $$ trying to track currents and tides and other
unpredictable phenomenon -- i.e., no more accurate predicting
a week ahead that 22 years ahead (2037).  Those folks who are
giving the software away must have other stuff they are trying
to sell.  :-)  I learned that the hard way trying some FREE
anti-spy, anti-pop-up, and anti-spam softwares, and ALL of
them wanted to sell me something FIRST.  Then they proved
that they didn't work.   I have several of the rat-ware
crawling on my other laptop now.  :-)

-- Bob.