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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