Minding the Helm Marine Navigation and Piloting (1994) / Chapter Skim
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G. A PRIMER ON NAVIGATION TECHNOLOGIES
G. A PRIMER ON NAVIGATION TECHNOLOGIES
Pages 434-448
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From page 434... ...
Off-ship navigation technologies and essential navigation publications are included. The descriptions are not comprehensive; there are a multitude of possible designs, uses, and combinations of many navigation technologies.
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From page 435... ...
This is a disadvantage in pilotage waters, because the view aft is obstructed, making it more difficult to visually ascertain ship motion relative to a confined waterway and other vessels that may be approach from abaft of the beam. Because visual navigation has been the primary means of maneuvering a ship, albeit supported by various modern navigational aids, the bridge almost always is surrounded- to the extent possible by windows.
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From page 436... ...
Electronic navigation refers to all techniques and systems that rely on electronic devices, including radio, radar, Loran C, and satellite navigation systems such as Transit and the Global Positioning System.i Electronic navigation also refers to inertial, bathymetric, and Doppler navigation, which have not attained broad use in merchant shipping. Inertial systems provide accurate dead reckoning (if they
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From page 437... ...
NAVIGATION TECHNOLOGIES: KEY FEATURES AND USES The anemometer indicates the speed and direction of the wind-essential data for estimating the compass heading required to achieve a desired course, part~cu larly when maneuvering in strong winds. Automated docking systems/docking assist systems comprise advanced sensor technologies (using velocity derived from lasers, microwave ranges, or Differential Global Positioning System EDGES]
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From page 438... ...
and compensating with changes in rudder angle. An autopilot may also be used to keep the ship on a passage plan trackline based on cross-track error information from electronic navigation instruments capable of storing voyage plans.
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From page 439... ...
The Differential Global Positioning System (DGPS) provides the capability accurate position fixes in harbors and harbor approaches by using data broadcasts (by the Coast Guard in the United States)
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From page 440... ...
Although the technology has been available for over a decade, interest in electronic charts has soared recently with the availability of reasonably priced computers for rapid manipulation of large amounts of chart data. At present, electronic charts have no legal status and are used only to supplement paper charts.
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From page 441... ...
It features Engine Order Telegraph or direct throttle control of main engines, lever control of bow and stern thrusters, and readouts of engine performance. 2The National Oceanic and Atmospheric Administration is developing a standardized, fully attributed electronic chart for use in ECDIS, but progress is slow, so leading equipment vendors and suppliers are developing their own electronic charts, which vary in content and completeness.
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From page 442... ...
is a Department of Defense radio navigation system using transmissions from satellites. It will provide very accurate and continuous worldwide position fixes in three dimensions through its initial constellation of 24 satellites.
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From page 443... ...
The gyrocompass features azimuth repeaters for visual bearings and course monitoring, and digital repeaters for course monitoring. Outputs from the gyrocompass can provide signals to the autopilot, rateof-turn indicator, ARPA, electronic navigation instruments, course recorder, satellite communications antenna, and ECDIS; gyrocompass outputs provide heading data for calculating steering corrections, set and drift, rate of turn, deadreckoned course, and alignment to changes in heading.
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From page 444... ...
Lights are used as shore reference points for ships, both to prevent groundings and to help with alignment in channels. Lights include fixed light structures, major floating lights, and ranges (e.g.
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From page 445... ...
Coast Pilots, published regularly by NOAA, provides irr£ormation on domestic navigation regulations, outstanding landmarks, channel SThe Shipboard Piloting Expert System program, under development by Rensselaer Polytechnic Institute, is sponsored by the Maritime Administration and the Coast Guard, with cost sharing by Sea-River Marine (formerly Exxon Shipping Company) and Sperry Marine.
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Similar information for other coasts can be found in the List of Lights, published annually by Defense Mapping Agency Hydrographic/ Topographic Center. Racons are aids to navigation that give an electronically enhanced radar signal.
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From page 447... ...
It is in almost universal use on deep-draft vessels. The steering stand is a console where the steering wheel, rudder angle indicator, autopilot, and backup steering systems are mounted.
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From page 448... ...
systems are a form of marine traffic regulation. VTS overlays a port and waterways complex with an organizational structure that enhances communication and interdependent decision making between vessels, improves order and predictability, and provides a capability for real-time operational oversight and traffic management by port safety and management authorities.
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