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63 CHAPTER 5 SHORT RANGE AIDS TO NAVIGATION DEFINING SHORT RANGE AIDS TO NAVIGATION 500. Terms And Definitions The term “short range aids to navigation” encompasses lighted and unlighted beacons, ranges, leading lights, buoys, and their associated sound signals. Each short range aid to navigation, commonly referred to as a NAVAID, fits within a system designed to warn the mariner of dangers and direct him toward safe water. An aid’s function deter- mines its color, shape, light characteristic, and sound. This chapter explains the U.S. Aids to Navigation System as well as the international IALA Maritime Buoyage System. The placement and maintenance of marine aids to nav- igation in U.S. waters is the responsibility of the United States Coast Guard. The Coast Guard maintains lighthous- es, radiobeacons, racons, Loran C, sound signals, buoys, and daybeacons on the navigable waters of the United States, its territories, and possessions. Additionally, the Coast Guard exercises control over privately owned navi- gation aid systems. A beacon is a stationary, visual navigation aid. Large lighthouses and small single-pile structures are both bea- cons. Lighted beacons are called lights ; unlighted beacons are daybeacons . All beacons exhibit a daymark of some sort. In the case of a lighthouse, the color and type of struc- ture are the daymarks. On small structures, these daymarks, consisting of colored geometric shapes called dayboards , often have lateral significance. Conversely, the markings on lighthouses and towers convey no lateral significance. FIXED LIGHTS 501. Major And Minor Lights Lights vary from tall, high intensity coastal lights to battery-powered lanterns on single wooden piles. Immov- able, highly visible, and accurately charted, fixed lights provide navigators with an excellent source for bearings. The structures are often distinctively colored to aid in iden- tification. See Figure 501a. A major light is a high-intensity light exhibited from a fixed structure or a marine site. Major lights include pri- mary seacoast lights and secondary lights. Primary seacoast lights are those major lights established for mak- ing landfall from sea and coastwise passages from headland to headland. Secondary lights are those major lights estab- lished at harbor entrances and other locations where high intensity and reliability are required. A minor light usually displays a light of low to mod- erate intensity. Minor lights are established in harbors, along channels, rivers, and in isolated locations. They usu- ally have numbering, coloring, and light and sound characteristics that are part of the lateral system of buoyage. Lighthouses are placed where they will be of most use: on prominent headlands, at harbor and port entrances, on isolated dangers, or at other points where mariners can best use them to fix their position. The lighthouse’s principal purpose is to support a light at a considerable height above the water, thereby increasing its geographic range. Support
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This note was uploaded on 10/25/2010 for the course HYDROGRAPH hydrograph taught by Professor Kolmogrov during the Spring '10 term at Universitas Katolik Parahyangan.

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