Dennis. Good guess but where else. Lot water on the surface of the earth

On Tue, Dec 18, 2018 at 3:46 PM Bruce Pope via CnC-List <
cnc-list@cnc-list.com> wrote:

> Thanks Dennis.
> Couldn't agree more.  I love this quote from NOAA Office of Coast Survey:
> "The age and accuracy of data on nautical charts can vary. Depth
> information on nautical charts, paper or digital, is based on data from the
> latest available hydrographic survey, which in many cases may be quite old.
> In too many cases, the data is more than 150 years old. Sometimes,
> particularly in Alaska, the depth measurements are so old that they may
> have originated from Captain Cook in 1778."
> My favorite - sailing directions for the south-west coast of Barbuda
> indicate the deepest water is relatively tight to shore.  We were
> paralleling the beach about 150m off and for about 20 minutes the chart
> plotter showed our position as driving down a road that runs just inland of
> the beach.
>
> ------------------------------
> *From:* Dennis C. <capt...@gmail.com>
> *Sent:* Tuesday, December 18, 2018 9:21 AM
> *To:* CnClist
>
> *Subject:* Stus-List Electronic navigation - chartplotters
>
> Over the weekend I brought Touche' back home to Mandeville for the
> winter.  Nice trip but a bit cold for my Southern blood.  Here's something
> I observed.
>
> For those who rely exclusively on charplotters and electronic navigation,
> here's something you need to look at.  Go to Google Earth and enter the
> following in the search window:   30°18'2.24"N 87°37'34.10"W
>
> That will take you to a marshy island in Portage Creek, a portion of the
> ICW near Orange Beach, AL.  That's where the GPS chartplotter showed the
> boat symbol representing Touche' was when Touche' was actually in the
> middle of the channel adjacent to island.  If I had been using the boat
> symbol for navigation and had been steering to keep the symbol mid-channel,
> Touche' would have been in the trees on the south bank of the ICW.
>
> The GPS continued to show Touche' in the trees on the north bank during
> the entire transit of this section of the ICW.  Having navigated these
> waters dozens of times, I'm very familiar with them but a boater transiting
> here the first time in heavy fog............................
>
> Once out of the man-made ICW the GPS returned to being fairly accurate.
>
> Just saying, once again, how important it is to use your eyeballs and not
> rely on electronics exclusively for navigation.  Maybe it doesn't seem like
> a big deal when you're in a channel that is well marked but there are lots
> of areas with no marks, no land and seriously shallow shoals or rocks.
>
> Dennis C.
> Touche' 35-1 #83
> Mandeville, LA
>
>
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