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Old 04-17-2010
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wwilson wwilson is offline
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Quote:
Originally Posted by LinekinBayCD View Post
...I'd be interested to hear from anyone who has found errors either in Maine or on the Chesapeake.
LinekinBayCD,

I smacked into a rock that may have been either incorrectly charted or uncharted. Have a look at the NOAA chart below (#13324).

We were poking very slowly around the northern end of Dyer Island looking for anchorage in Dyer's Northeast Cove. We had rounded G"3" in the Dyer Narrows and were in the proximity of the Green/Red mark off the west side of Strout Island.

Dyer I. Northeast Cove


Our depth sounder was in agreement with the chart plotters that we were in 25-foot depths at 44˚31.037'N x 67˚48.389'W. Those coordinates, from my Garmin 3205 chart plotter using its built in BlueChart cartography. When I plot those coordinates on electronic charts today they appear right up against the western shore of Strout I. - just across from the Green/Red mark. That was certainly not the case! Our DR navigation had us mid channel. The nav station's Raymarine chart plotter using C-Map cartography was in agreement with the Garmin, they are independent systems.

The chart symbol just NW of the Green/Red is, "dangerous underwater rock of uncertain depth" according to NOAA Chart #1 definition. Given its surrounding depth of 19 - 26 foot spot soundings - I believe we may have hit that rock. The distance from the coordinates that I saved to the outer edge of the rock is 0.11-nm or about 668-ft. NOAA's stated cartography accuracy for a 1:40,000 scale chart is ~40-meters or 131-feet. It is possible, maybe even likely that the charted rock was not what we hit. I know that the tide was flooding - because it lifted us off the rock within minutes. It would have been pushing us in the general direction of Shag Island.

NOAA Chart #13324


By the time of impact we were well into "VFR", steering from mark to mark using visual DR and proceeding at dead slow through a sea of lobster trap floats on a clear sunny afternoon with unlimited visability.

Here is our Maine Memento (now repaired) which our Maine friends tell us initiates us "officially" into the Cruising Club of Maine.

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Last edited by wwilson; 04-19-2010 at 09:45 PM.
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