国际航行英语 4船上娱乐 Costal and Ocean Navigation20191206 (1).pptx

Costal and Ocean NavigationUnit 13 Types of MarksLateral marks are buoys or beacons indicating the port and starboard sides of a route to be followed, and are used in conjunction with a conventional direction of buoyage.Lateral marksTypes of MarksPreferred channel marks are aids to navigation which mark channel junctions or bifurcations and often mark wrecks or obstructions. Preferred channel marks may normally be passed on either side by a vessel, but indicate to the mariner the preferred channel. Preferred channel marks are colored with red and green bands.Preferred channel marks Buoys and BeaconsThe IALA maritime buoyage guidelines apply to buoys and beacons that indicate the lateral limits of navigable channels, obstructions, other dangers such as wrecks, and other areas or features of importance to the mariner. This system provides five types of marks: lateral marks, safe watermarks, special marks, isolated danger marks and cardinal marks. Each type of mark is differentiated from other types by distinctive colors, shapes and light rhythms.II Buoys and BeaconsBuoy moorings vary in length. The mooring lengths define a watch circle, and buoys can be expected to move within this circle. Actual watch circles do not coincide with the symbols representing them on charts. Buoys and BeaconsBeacons are aids to navigation which are permanently fixed to the earth’s surface. These structures range from lighthouses to small unlighted daybeacons, and exhibit a daymark to make these aids to navigation readily visible and easily identifiable against background conditions. The daymark conveys to the mariner, during daylight hours, the same significance as does the aid to navigation’ s light at night.Buoys and BeaconsVessels should not pass fixed aids to navigation close aboard due to the danger of collision with rip-rap or structure foundations, or with the obstruction or danger being marked.Lighted Aids to NavigationA light of low intensity will be easily obscured by unfavorabl