Re: How far can you see over water from a ship?

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: : Ken, I hope you really wanted to know. Here goes: : : If you want to know the distance to the horizon you simply have to know your "height of eye". That is the distance that your eyes are off the surface of the water. If you're in a jon boat, that would probably be about three feet (if you are sitting like you should be in a jon boat). If you were standing at the water's edge, your height of eye is the distance from your eye to your feet. : : 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 : : 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. : : As you can imagine, because of the curvature of the earth, the higher your height of eye the farther you can see, and vice versa. : : And, if you're referring to chief engineer Mc Clure of the Chicora ("All is lost, could see land if not snowed and blowed. Engine give out, drifting to shore in ice. : : Captain and clerk are swept off. We have a hard time of it. 10:15 o'clock." ), no one has proven that the message in the bottle was not a fake. : : Interesting concept though! : : Craig Rich : : : : A written victum report from a shipwreck I was researching states "we could see land if it weren't for the snow." I was wondering if anyone knew how far a person can usually see in the Great Lakes from the deck of a large ship and how this distance is affected by weather beyond the obvious. For instance, if they faintly thought they could see shore, would this mean they were closer than they'd be in good weather. This, in my case, might help position this wreck. : Thanks Craig, Exactly what I wanted to know. "And now I know where she is"

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