Search results
Results from the WOW.Com Content Network
Watercraft navigation lights must permit other vessels to determine the type and relative angle of a vessel, and thus decide if there is a danger of collision. In general, sailing vessels are required to carry a green light that shines from dead ahead to 2 points (22 + 1 ⁄ 2 °) abaft [note 1] the beam on the starboard side (the right side from the perspective of someone on board facing ...
Some signal lamps are mounted on the mastheads of ships while some small hand-held versions are also used. Other more powerful versions are mounted on pedestals. These larger ones use a carbon arc lamp as their light source, with a diameter of 20 inches (510 mm). These can be used to signal to the horizon, even in conditions of bright sunlight.
An example of a complete light characteristic is "Gp Oc(3) W 10s 15m 10M". This indicates that the light is a group occulting light in which a group of three eclipses repeat every 10 seconds; the light is white; the light is 15 metres above the chart datum and the nominal range is 10 nautical miles.
The International Code of Signals was preceded by a variety of naval signals and private signals, most notably Marryat's Code, the most widely used code flags prior to 1857. What is now the International Code of Signals was drafted in 1855 by the British Board of Trade and published in 1857 as the Commercial Code. It came in two parts: the ...
The appropriate lights may also be displayed during the day at times of restricted visibility or other necessary circumstances. [3] Vessels under 7 meters are generally not required to display day shapes even if they are required to display lights at night. [4] A square black flag displayed over the ball may be used as a distress signal. [5]
Customarily, the upper mark is up-hill from the lower (forward) mark. The mariner will know the geometry of the marks/lights from the navigational chart and can understand that when "open" (not one above the other) the ship needs to be navigated to "close" the marks (so one is above the other) and be in the preferred line of the channel.
When the wave-off lights are lit, all other lamps are extinguished. The wave-off lights are operated manually by the LSO. Some (particularly later) optical landing systems include additional lamps: Cut lights – Green lamps used to signal different things based on where the approaching aircraft is in its approach. Named for its original use in ...
In a wider sense the phrase "sea mark" is often understood to include all types of landmarks, structures and devices that can be used to provide warning and guiding signs to mariners. Thus a sea mark can be and often is located on dry land. Examples of land-based sea marks are various signal lights and leading marks.