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HARBOR AND PORT AIDS TO NAVIGATION Commander Guy Clark Aids to navigation are devices external to vessels that are designed and placed to help mariners in the safe navigation of their vessels. The mariner has two concerns in navigating the entrance to a port or harbor: first, avoiding collisions with other ships, and second, knowing where the vessel is on the face of the earth relative to fixed hazards. This latter concern--positional navigation--is addressed by harbor and port aids to navigation. Perhaps the first aids most people think of are lighthouses, buoys, and lightships. As there is only one lightship station left in the United States, the lightship is almost a thing of the past. The aids we provide are planned as co-located systems of signals--a daytime visual system, for example, and a nighttime visual system. There are also electronic signals--racons and radar reflectors to assist radar navigation--radio-navigation systems, and of course, traditional sound systems for warnings of last recourse. It is most convenient to co-locate these systems. The buoy marking the Galveston Bay entrance, for example, is equipped with a light for nighttime visibility and a structure for daytime visibility, racon and radar reflectors, and a whistle. These aids to navigation are passive: they do not replace the navigator. It is hoped that mariners will use them for their intended purpose, but the investigation of casualties often indicates that the aids provided were not used, or that they were not used properly. This, together with the fact that the Coast Guard provides and maintains more than 50,000 aids at a cost of more than $100 million a year, raises the questions: What systems are most important? Which do mariners need most? The answer is complicated by the fact that mariners sometimes use one system, and at other times, another. A system that serves perfectly well in some conditions may be inadequate in others. Recreational sailors seem to like buoys because they're unmistakably nautical, particularly if a pelican or seagull is perched on top, but in our opinion, buoys are inferior to fixed beacons as aids to navigation. Ten years ago, the Coast Guard initiated a program to replace buoys with beacons for greater economy as well a" better navigational service. There were many objections, and come serious problems. We 35

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36 found that tugboats in certain areas used the beacons to assist them in negotiating their turns, leaning their tows against them and pivoting. A few 90 turns easily destroyed these beacons. As buoys are sometimes less expensive to replace than beacons, the Coast Guard has been forced to reverse its program in some areas. The basic principles we follow in planning and placing aids to navigation in and near ports and harbors are to mark the channel and the safe passages, signal the presence of obstructions or hazards, and to respond to requests for additional aids wherever reasonable and feasible. We rely on knowledge, common sense, and experience. Having recently returned to Coast Guard headquarters as the Chief of the Signal Management Branch of the Short Range Aids to Navigation Division, I have been giving considerable thought to the need to improve our service to mariners, and to gain better understanding of the man-system interactions and other factors that are most important to navigation. Such considerations point to additional research, perhaps with the use of simulators. In its Latin roots, the word "navigate" means to go from place to place by ship, and from at least as long ago as the word's origin, mankind has searched for better ways to navigate. DISCUSSION WEBSTER: T would like to reiterate a question that has been asked of Captain Charter. In replacement of the buoys, you say that you do not use simulations to determine the best place for them, but rather mark areas where ships might go (or have gone) aground? CLARR: We have been aware for some time that we need some type of analytical tool to compare one configuration of aids with another for a given harbor to determine which is better and whether the improvement is worth the difference in, say, cost. We did initiate a research and development effort to define the performance to be expected of aids to navigation, and to evaluate existing and proposed systems of aids. The use of simulations is an interesting possibility that we may hear more about in the presentation scheduled on the subject of shipboard aids to navigation. WIEGEL: In one of the panel's planning sessions for this meeting, a representative of the Coast Guard mentioned that one piece of information the navigator would like to have about an area is the prevailing currents. There are current charts, of course, but as you know, very often the difference between the actual and the predicted currents is significant. Has the Coast Guard given thought to placing current meters in certain critical channels that the ships could interrogate and get data back, for real-time information on currents? CLARK: I am not aware of any plans to try such an arrangement, but they may exist. Speaking as a sailor, I always want

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37 to have total knowledge of currents and other conditions that impart relative motion to the vessel, to compensate for it. Translating this desire into navigational aids, however, raises many questions about the kinds and amounts of information to be imparted, and the most useful ways of conveying or displaying it. KNIERIM: What about the possibility of data-gatbering programs that would give harbor pilots, for example, more accurate and complete charts of winds, waves, tides, and currents? CLARK: I think that is a good point. The Coast Guard, to the best of my knowledge, does not maintain any tide or current gauges for the sake of providing information of this type. The ones I have seen have all belonged to other agencies. NOAA (the National Oceanic and Atmospheric Administration), of course, collects the information and provides tables. I think part of the question here is, if this is useful, who should be doing it? LE BACK: It is not that expensive to do it. We did an extensive experiment in tidal analysis after two LNG (liguefied natural gas) terminals were built, and we developed a set of tables for the pilots that enabled them to judge wind direction better, as well as the various stages of the tide, and what the current was doing. I don't think this should be done by the federal government. The government can bog itself down in a million-dollar study of something that would cost a private operator or port authority perhaps four or five thousand dollar". Port authorities should conduct such programs and make the information available to the users.

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