摘要 :
The report represents the result of an effort to establish a data file of reference material for U.S. lightships. It is not a story per se, but rather a collection of data outlining the description, service and history of lightshi...
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The report represents the result of an effort to establish a data file of reference material for U.S. lightships. It is not a story per se, but rather a collection of data outlining the description, service and history of lightships and their stations. Only those lightvessels and stations authorized and maintained by the United States Government have been included, omitting entirely the plethora of private 'floating lights' of various types that existed over the years. The material consists of two major components - the first deals with the light vessels themselves, and the second covers the lightship stations. Although there is some redundance between these two, each is mutually supportive.
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We evaluated the effectiveness as an aid to navigation a single-station beacon which was white when viewed from the centerline of a channel and became increasingly red or green when viewed from off center to the right and left. Fi...
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We evaluated the effectiveness as an aid to navigation a single-station beacon which was white when viewed from the centerline of a channel and became increasingly red or green when viewed from off center to the right and left. First we measured the observers' ability to determine whether a light was white, reddish, or greenish. A wide range of colors, from 575 nm to 585 nm, were judged to be white, making it difficult to specify a beacon that would adequately signal center of channel. Second, we measured the ability of the observers to detect a change in color for slowly changing stimuli. There were seven just noticeable differences in the range of color investigated. This would provide a sensitivity of 21.8 m (71.4 ft) over a 152 m (500 ft) wide channel. Measurements were taken with and without a 'white' reference light. Under no condition did the reference light improve performance. For changing stimuli, however, those that were brighter or larger provided better sensitivity than those that were small or dim.
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The National Register of Historic Places is an important tool for maritimepreservation. Utilizing uniform National Register criteria to evaluate significance and integrity is an important first step in planning for the preservatio...
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The National Register of Historic Places is an important tool for maritimepreservation. Utilizing uniform National Register criteria to evaluate significance and integrity is an important first step in planning for the preservation of historic aids to navigation. Listing an aid to navigation in the National Register provides an incentive for preservation by recognizing it as being significant and worthy of preservation.
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An investigation was made of the deficient conspicuity of navigation lights in harbors. This problem can be solved,and the problem requires two distinct solutions,both of which are necessary. The first solution is the development ...
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An investigation was made of the deficient conspicuity of navigation lights in harbors. This problem can be solved,and the problem requires two distinct solutions,both of which are necessary. The first solution is the development of what should be considered only short-term measures. The second solution is the regulation of lights that interfere with the conspicuity of navigation lights. This is the only permanent solution to the problem,for purely technical solutions would only involve the Coast Guard in a never-ending struggle to keep one step ahead or,worse,keep up with new types of lights that are being installed along the shoreline. (Author)
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A study was conducted to determine whether or not navigation safety is affected when the masthead light is placed aft of amidships and aft of the sidelights light on power driven vessels less than 50 meters in length that have a s...
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A study was conducted to determine whether or not navigation safety is affected when the masthead light is placed aft of amidships and aft of the sidelights light on power driven vessels less than 50 meters in length that have a single masthead light. Computer simulation was used to display oncoming vessels to observers. Vessels were represented only by their navigation lights, which were not always placed in compliance with current regulations. Observers were not informed of the actual navigation light placements, which is akin to the situation on the open water. Two different situations were simulated. In one situation, observers had to judge aspect after a brief look at an oncoming vessel, simular to the situation when an oncoming vessel is first noticed. In the other situation, observers were given a long period of time to watch an oncoming vessel. These observers were asked to judge the vessel's course. In both situations there was no statistically significant difference between the responses given when vessels complied with current regulations and responses given when the masthead was free to vary forward and aft of the sidelights. Keywords: Navigational, lights, Computerized stimulation, Naval vessels,merchant vessels, surface navigation. (rwj)
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Tests were performed to determine any adverse effect from the use of a 'switching'voltage regulator on the performances of marine signal lamps and air-depolarized primary batteries,commonly used in minor lighted aids to maritime n...
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Tests were performed to determine any adverse effect from the use of a 'switching'voltage regulator on the performances of marine signal lamps and air-depolarized primary batteries,commonly used in minor lighted aids to maritime navigation. The purpose of this interim report is to provide the results of these tests to date.
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The report describes the design, development and fabrication of a prototype high intensity obstruction lighting system. A detailed light source study was made which indicated a newly developed lamp consisting of a quartz-iodide la...
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The report describes the design, development and fabrication of a prototype high intensity obstruction lighting system. A detailed light source study was made which indicated a newly developed lamp consisting of a quartz-iodide lamp sealed in a parabolic envelope, was the most advantageous type light source. The lamp was operated at less than rated current so that the life was extended to 10,000 hours on the specified operating cycle. In order to obtain the dimming required, the lamps were connected in a series and film disc cutouts were installed so that the burn out of one lamp would not stop current flow in the other lamps. A current regulator was used to maintain the current thru the remaining lamps constant even after some lamp burn outs. The methods utilized in rotation and synchronization are discussed. A stepping motor is used for rotating and a light activated switch arrangement is used for syncronization. The test procedures and test report are included in the report. It is concluded that the light system meets the contract requirements and it is recommended that the F.A.A. accept the light system (Author)
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A marine lantern was recently introduced with a 300mm Fresnel acrylic plastic lens. Marine signal lanterns of this construction in 155mm and 250mm sizes have previously been photometrically tested and found to be more efficient th...
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A marine lantern was recently introduced with a 300mm Fresnel acrylic plastic lens. Marine signal lanterns of this construction in 155mm and 250mm sizes have previously been photometrically tested and found to be more efficient than lanterns using pressed glass Fresnel lenses. A comparison test of all three acrylic plastic lenses is described herein. Photometric characteristics of the lanterns were measured using the same marine signal lamps and six-place lampchanger for all lanterns to afford direct comparison. (Author)
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A study was conducted to determine whether or not navigation safety is affectedby the size of the vertical sector of navigation lights on unmanned barges. Off-the-shelf equipment was purchased and tested to ascertain the performan...
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A study was conducted to determine whether or not navigation safety is affectedby the size of the vertical sector of navigation lights on unmanned barges. Off-the-shelf equipment was purchased and tested to ascertain the performance of existing lighting equipment against COLREGS requirements. The purpose served by vertical sector was defined, and a 'minimum' luminous intensity distribution was created as a standard against which off-the-shelf and COLREGS lights could be judged. An analysis was performed to determine the power requirement for a COLREGS light. None of the off-the-shelf equipment tested met the COLREGS specification. Some exceeded the 'minimum' luminous intensity distribution with up to a 1.5 degree margin for error. The COLREGS luminous intensity distribution provided a 4.5 degree margin for error. The power needed to meet all the requirements of the COLREGS is feasible, but not easy to produce with batteries.
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