GPS's are great, aren't they?
My GPS 198C put me right in a slip. When tied up, the only difference was
that the GPS indicated I was on the right side when I was centered in a two
boat slip.
The key is to avoid constant heading/speed changes, so the GPS can keep up
with your progress.
Quite a confidence builder.
But, we'll never be without a paper chart on my boat, and the radar's always
on and a lookout posted. Even on nice, sunny days.


"Gordon Wedman" wrote in message
news:WtoIf.1208$n67.820@edtnps89...

"Len Krauss" wrote in message
...
Having a little problem with my chart display showing my position approx
150
ft west of actual, I checked chart datum (NOAA BSB raster type) and
found
it was NAD83, whereas my GPS (non-WAAS) had been set to WGS84. So just
for
the heck of it I set the GPS to NAD83. That didn't correct the position
error. From what I understand, WGS84 and NAD83 are practically
identical,
so is there any reason not to just leave GPS set to WGS84 (this is in SW
Florida, USA)?

Any advice on what else to check to correct the westerly error would be
appreciated. (using Capn nav software and Garmin GPS 48).

Thanks,
Len

My Garmin 182C with the latest Blue Chip puts my boat exactly where it
should be in my marina. Right on the correct finger.
I recently bought Ozi Explorer and a friend gave me a set of older charts
on CD. With this set-up my boat is 150 yards too far North-East. I
thought it might be the datums but no other datum gave better results than
WGS4. I bought the latest paper chart for the area and plotted the L/L
shown on the laptop. Exactly correct on the new chart. So the old chart
on the CD was inaccurate by 150 yards in terms of the location of my
marina. I imagine it is more accurate for navigational hazards but it
makes you wonder.