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 > > > _______________________________________________ > > Thanks everyone for supporting this list with your contributions. Each > and every one is greatly appreciated. If you want to support the list - > use PayPal to send contribution -- https://www.paypal.me/stumurray > > -- Sent from Gmail Mobile
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