capability. Tides, currents, and Coast Pilot-type information will be published in hard copy and on the Internet and updated through electronic transmissions in varying degrees of detail (e.g., more detailed for big commercial ships and less detailed for recreational boats). However, because shipboard systems are not likely to match the speed of land-line data connections (now 28,800 bits per second) in the near future, some files, especially long or graphics-laden documents, may take too long to download from the Internet to benefit mariners.

Precision electronic navigation technology, such as DGPS, has already proven to be extremely accurate. In the future, fixing positions in all weather will not only be possible (as it is today) but will also be reliable. Prudent mariners, however, will continue to fix their positions by multiple, independent means when their vessels are close to hazards or in constricted waterways, especially when visibility is poor.2 In other words, the mariner of the future will not rely solely on any one technology but will continue to exercise his or her critical judgment and will have the necessary training and qualifications to do so.

Other Vessels

In the future, mariners will be able to detect the presence and determine the position of other vessels quickly and accurately, regardless of weather or location. They will also have the tools to make sound decisions about taking evasive action, if necessary. All vessels will be equipped with AIS, which will be linked to shore-based VTS systems in busy harbors.

AIS, in combination with precision navigation systems, will become a critical tool for detecting other ships and selecting anticollision strategies, especially in low visibility. This technology suite will enable mariners on the bridges of two or more vessels to identify each other and exchange information silently and immediately on their courses and speed. "Silent, bridge-to-bridge VTS" will be tested in a prototype installation in the AIS pilot project on the Lower Mississippi River. Similar systems in Alaska, Canada, and Europe have demonstrated their usefulness in close-quarters situations and in avoiding collisions.

This "VTS of the future" will have many advantages over radar (which cannot "see" around corners, such as islands) and will enable mariners to interact over dedicated frequencies that are not blocked by competing or extraneous transmissions. Silent, screen-to-screen interactions will enable mariners to communicate when and how they choose, eliminating the distraction of constantly monitoring VHF channels from several vessels and sometimes from shore.

The success of the "VTS of the future" will depend on all vessels (or at least all vessels above a certain size) carrying internationally compatible transponders and other equipment and all operators being trained in their use. The equipment will be internationally interchangeable and not dependent on unique or proprietary technology. Future VTS systems will be easy to use and affordable. Fortunately, the proliferation of electronic equipment and the tendency for prices to decline over time suggests that this vision of the future can be achieved.

Traditional systems, such as radar, automatic radar plotting aid,3 and VHF radio, will continue to be used for redundancy and to ensure reliability. Furthermore, in most heavily trafficked harbors, an information link to a shore-based VTS system will provide both information and active traffic management by the appropriate authority, when necessary.

Realizing the Vision

Realizing the vision described above will not be easy. A firm foundation will first have be laid so that the most effective systems can be widely deployed in the United States. The committee identified eight elements of this firm foundation.

Coordinated National Policy on the Maritime Information Infrastructure

At least four federal agencies are currently responsible for various types of information and data critical to the navigation of vessels. USACE is responsible for channel maintenance and inland waterway operation, including locks on federal systems; NOAA is responsible for hydrographic surveys, charts, bathymetric data, Coast Pilot information, and weather information; the USCG is responsible for aids to navigation, Notices to Mariners, navigational broadcasts, List of Lights, and VTS; and the National Imagery and Mapping Agency is responsible for rebroadcasting some information from Notices to Mariners, keeping track of mobile drilling rigs and acts of violence directed against shipping, the Navigation Information Network, and sailing directions.

The effective use of the data depends on the capability of these agencies to coordinate their activities, set common priorities for collecting and disseminating data, and cooperate in the delivery of services to users. Too often mariners must evaluate a variety of services and sources to determine which one is most accurate and reliable in a given situation. A coordinated policy on the development and support of the maritime information infrastructure would eliminate, or at least lessen, this uncertainty. Coordinated planning could provide mariners with the most accurate data on a timely basis in a user-oriented format.


DGPS has some limitations when used in constricted waterways (USCG, 1997).


Automatic radar plotting aid is a computer that quickly and automatically plots radar targets based on information about the target vessel's course and speed. It is used to assess passing or overtaking situations and can help prevent collisions.

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