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post #9 of Old 07-19-2011
jackdale
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Quote:
Originally Posted by Boasun View Post
The USCG would have to punch up the power of the light in order to see it at a greater range.
Not quite.

There an visbility scale that can used in comjunction with a nominal range diagram.


Yards
0 Dense fog . . . . . . . . . . . . . . . . . Less than 50
1 Thick fog . . . . . . . . . . . . . . . . . . . . . .50-200
2 Moderate fog . . . . . . . . . . . . . . . . . .200-500
3 Light fog . . . . . . . . . . . . . . . . . . . .500-1000
Nautical Miles
4 Thin fog . . . . . . . . . . . . . . . . . . . . . . . . 1/2-1
5 Haze . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-2
6 Light Haze . . . . . . . . . . . . . . . . . . . . 2-5 1/2
7 Clear . . . . . . . . . . . . . . . . . . . . . . . . 5 1/2-11
8 Very Clear . . . . . . . . . . . . . . . . . . 11.0-27.0.
9 Exceptionally Clear . . . . . . . . . . . Over 27.0



from Bowditch online. http://www.irbs.com/bowditch/pdf/chapt04.pdf

An exceptionally clear night would be 15 miles, the geographic range.

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