Chuck Cox wrote:
SynchroSystems has a design concept for a low-cost, very low-power
electronic tide predictor that we are considering dusting off for a
design competition. Although we don't have any plans to market it as
a product at this time, I'd like to get some feedback about how such a
device might actually be used. It would be pocket-sized and should be
able to run for a year on a pair of AA batteries. If it were to be
manufactured, it would probably retail for around $100.

My market research indicates that there are basically two types of
tide clocks on the market: a simple diurnal clock that rotates the
hand every sidereal day and chartplotters with "real-time tide &
current data". The diurnal clock is a reasonable analog indication of
when high & low tide occur, but provides no depth prediction. I'm
not sure what the chartplotters are doing, but they should be capable
of doing a proper harmonic prediction, including depth. Can anyone
tell me about the tide prediction the chartplotters offer? Are there
less expensive electronic predictors that I missed?

Assuming expensive chartplotters offer acceptable tidal prediction,
the "market" for our device would be limited to boats without a
chartplotter. What kind of tidal prediction accuracy does such a
boater need? From my experience, I would be happy with +- 10 minutes
and +- 1 foot of accuracy, but I'd be interested in what you would
consider acceptable. The less resolution we can tolerate, the more
coastline we can stuff into the chip. I'd also be interested in how
far into the future you would like to predict. I'm usually only
interested in the next 2 tides, but I'd be interested in your
requirements. We can predict far into the future, but unnecessary
calculations waste battery power and clutter the user interface.

There are three ways we could determine which reference point to use:
manual selection, direct serial connection to a GPS unit or listen on
an NMEA network with a GPS talker on it. I'd be interested in your
preferences.

Thanks in advance for your thoughts.

Mapsource tidal predictions show the date and time now, the harmonic "wave"
in graphic form, showing predicted heights and times of HW and LW. There is
also the facility to change the date and time to any desired data. The
facility is available for all tide stations within the boundaries of the
particular Bluechart area you are running.

A similar program, with perhaps slighly more functions, can be used by any
boat with a laptop or PC without the need for a chartplotter. This is
WXTIDE32.exe, and as far as I am aware this program is available for free
download for most areas of the world except the UK, where the UKHO claim
Crown Copyright on all tidal data, presumably because the Sovereign can
alter the tides at will.

Dennis.