Jim Donohue wrote:

In the heavy boat business I would have thought two or three GPS receivers
would be standard aside from any additions like LORAN. Three is a little
magic because it almost always allows you to isolate the mis-behaving unit.

As stated, two are standard ...... three is overkill. After all, with
multiple radar, Loran, fathometer, celestial capabilities, etc., they
have any number of proven methods to navigate to their destination with
the needed accuracy, and it's not like a GPS unit is all that frequently
breaking down.

I don't think you can integrate radar into such a system. You can show the
picture or the picture enhanced but the software to match a view to a map
would be very difficult. If however you know where you are (or think you
do) it is possible that you might match the patterns. Cross check
perhaps...but quite sophisticated software.

All ready being done. I was looking at a chart overlay on a Radar,
yesterday. Noted that the plotted position and radar position for the
Seabuoy had a significant (to me) difference ( we can all understand the
possible problems this could create). I didn't have time to determine if
the difference was a plotting, alignment, or off-station problem.
Later on I was looking at a chart plotter (Based on Admiralty charts)
and noted that a particular Range line showed slightly right of channel
centerline. In actuality, it's slightly left.
EG In both cases, since I was employing other methods as checks,
neither problem (admittedly both were extremely minor and should not
have created a problem even for someone unfamiliar with the area) caused
me any grief and were filed away as "possible discrepancies to look for".


Of course your people can cross check radar and fathometer. If you can keep
them focused to do so. A known hard problem.

G Not really. If you consider the number of ships at sea on any given
day, plus mileage traveled and the overall accident rate (which no doubt
has plenty of room for improvement) then the percentage of failures is
fairly small, coupled with the fact that for all the cases such as the
Royal Majesty that we hear of, are the many cases that the problem was
observed and corrected, so consequently, never heard of.

otn