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Bedrock Of The Community
Australia
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Yeah! me too,
So I cheated and went to Google
Once you know your height of eye you simply plug that into the following formula:
1.17 times the square root of your height of eye = Distance to the horizon in nautical miles
For example, let's say you are on the water in a friend's sport fishing boat and your height of eye is 9 feet above the surface of the water. The formula to calculate distance to the horizon is:
1.17 times the square root of 9 = Distance to the horizon in nautical miles.
1.17 * 3 = 3.51 nautical miles
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If you want to calculate the distance at which an object becomes visible, you must know your height of eye and the height of the object. You then do the same calculation for your distance to the horizon and the object's distance to the horizon and add the distances together. For example:
You have the same height of eye of 9 feet so your distance to the horizon is still 3.51 nautical miles. You're approaching a port that has a lighthouse that is shown on your chart to have a height of 81 feet. Using the same formula you would find that 1.17 times the square root of 81 (1.17 * 9) = 10.53 nautical miles (the light house can be seen 10.53 nautical miles over the horizon)
By adding the two together: 3.51 + 10.53 = 14.04 nautical miles, you should be able to see the lighthouse when you are 14.04 nautical miles away.
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| Edited by rod222 - 04/22/2011 04:18 am |
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Pillar Of The Community
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Rod, thanks for that interesting info. Keep the pics coming everyone. Steve  |
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Bedrock Of The Community
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A Philatelic mind
is a terrible thing to waste |
| Edited by bobgggg - 04/27/2011 11:24 am |
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Valued Member
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Pillar Of The Community
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My modest contribution (I don't think these have been posted to this thread yet)  A couple of lighthouses from Singapore. Horsburgh Lighthouse on the left, and Raffles Lighthouse on the right. |
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Pillar Of The Community
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Bedrock Of The Community
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Iceland 1978 Centenary of Icelandic lighthouses  |
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| Edited by timbres667 - 04/30/2011 05:46 am |
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Pillar Of The Community
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Pillar Of The Community
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Replies: 341 / Views: 76,294 |
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Posted 04/22/2011 04:08 am
