Range Lights

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In nautical terms, Range Lights are lights that assist the navigation of ships, vessels and other watercraft into defined channels, lanes or port and harbour entrances.

Range lights are often confused as being lighthouses, as they are often built to look like lighthouse structures. However, range lights only generally display a fixed red light, much smaller than the large rotating beam of light from a lighthouse.

Range lights take on many forms. Some are mounted on steel lattice towers, some are located on huge poles or even on the roof tops of coastal buildings. Some range lights look strange, and can be located in the most bizarre areas.

[edit] Operation

Two lights are positioned in front of one another. One, known as the front light, is shorter than the other one behind it, which is referred to as a rear light. At night when viewed from a ship, the two lights become aligned directly above one another when the captain of the vessel is heading on a straight course. If the veseel is on an incorrect course, the lights wouldn't line up. The front light would appear slightly left of the rear light, for example.

During the day, the lights can't easily be seen and therefore range lights are fitted with secondary visual aids, often huge red flags with thick black lines running down them. When both red flags and black lines line up, the captain will again know that the vessel is on the correct course.

Range lights are used to help a captain or pilot make an approach to a port entrance, or navigate a very narrow channel.

For example, a narrow channel might have shallow water at each side but deep water in the middle. If the ship veers off to either side, it risks being grounded on the sea or river bed. But as long as it stays in the middle of the channel or river, it will stay out of danger because the water is deep enough. To help the captain stay in the middle of the river, he or she lines up the front (stern) end of the vessel with the aligned range lights or marks, and continues along that bearing.

Some rivers, such as the Elbe River in Germany, have a series of ranges. Each time it is necessary to make a turn, the navigator lines up the next pair of range lights. This provides guidance from Hamburg to the sea, using successive pairs of range lights.

The first set of range lights in the United States were privately established by subscription at Newburyport Harbor in Massachusetts in 1788. ^[1] This technology was first used in Europe in 1837, where they are referred to as Leading Lights.

Range lights and marks are also used for pilotage to determine a vessel's exact location at sea.

[edit] References