United States Merchant Marine Academy - Midships Yearbook (Kings Point, NY)

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equal upon the high seas. There is no chance for error in close pilot waters, for the misinterpretation of a single light can spell disaster for the unwary mariner. The corrected nautical chart, combined with pub- lished listings of lights and their characteristics, is the mariner’s most trusted friend when in pilot waters. Containing pertinent data about the waters the vessel is navigating, the charts also distinguish the various lights in the area, their characteristics, heights, special fog signals, and if the light is a radio beacon, necessary radio information. Using the chart the navigator keeps a continual running account of the position of his vessel, and determines what courses he must make good to bring her safely into port. As the lights slide by, one by one, the mariner silently praises the wonders and certainty of the modern apparatus and the devoted energies of those men and women who care for them. For centuries the only effective means for providing the light necessary to guide the mariner was the glow and smoke from an open fire. Even as late as 1814, the Tour de Cordauan of the Firth of Forth was lighted in this manner. As helpful as they often were, these lights were far from being efficient and reliable. They turn to smoke in rain and flicker beyond cer- tainty in high winds. Many mariners believed it was better not to show the light at all, rather than to show it irregularly. Gradually, as the discovery of the new world in- creased the volume of waterborne commerce, the need for better lights was apparent. Crude coal and wood burning fires gave way to tallow candles at first, and later to oil blazes of sperm, lard, fish, and colza oils. Experimenting resulted in the chandelier blaze holder in which several oil blazes were positioned about the circumference of the chandelier. Small parabolic reflectors were placed behind each blaze to make the most efficient use of the light. In 1898, the first incandescent oil vapor lamp using kerosene was introduced in France, providing a brilliant beam with a small consumption in fuel. The first electric lamp used in this country was in 1886 with the placing of an arc in the Statue of Liberty. Today the majority of lighthouses in this country use electric power, but there are still many located in remote regions employ- ing oil and acetylene vaporized lamps. Lenses were used as early as 1790 in England, but it was not until 1822 that the French physicist, Augustin Fresnel, developed a revolutionary lens design. As Putnam describes it, it was: a built-up lens comprised of a central spherical lens surrounded by a ring of glass prisms, the central portions of which refract and the outer portions both reflect and refract in the desired direction the light from a single lamp placed at the central focus. Variations of this basic lens are used throughout this country today. The lens at Montauk Point Light Station is, for example, a modern adaptation of the CHARACTERISTICS: The distinctive characteristics of all types of lights can all be broken down into a few simple basic indications, the combinations of which pro- duce the varied displays of many lighthouses. This diagram contains these basic characteristics and their abbreviations as found on nautical charts. MAKAPUU LIGHT: The lens in Makapuu Point Light, Hawaii, is the largest lens in the United States. AIDS TO MARINE NAVIGATION OF THE UNITED STATES CHARACTERISTIC LIGHT PHASES Illustration 11111111111111111111111 unii min ■ I ■ I I II II 11= Symbols and meaning Lights which do not change color Lights which show color variations Phase description F.-Fixed Alt.-Alternat- ing. A continuous steady light. F. FI.-Fixed and flashing. Alt. F. FI = Al- ternating fixed and flashing. A fixed light varied at regular intervals by a flash of greater brill! ance. F. Gp. Fl.= Fixed and group flash- Alt. F. Op. FI.™ Alternating fixed and group flashing. A fixed light varied at regular Intervals by groups of 2 or more flashes of greater brilll ance. FI. — Flashing. Alt. FI.-Alter- nating flash- ing. Showing a single flash at regular Intervals, the duration of light al- ways being less than the duration of dark- ness. Shows not more than 30 flashes per minute. Op. Fl.™ Group flash- ing. Alt. Op. Fl.- Alternating group flash- ing. Showing at regular In- tervals groups of 2 or more flashes. Q k . F 1 = Quick flash- ing. flashes per minute. Shows quick flashes for about 4 seconds, fol- lowed by a dark period of about 4 seconds. I. Qk. FI.™ Interrupted quick flash- ing. Short-long flashing. about 0.4 second, fol- lowed by a long flash of 4 times that dura- tion. Occ.= Occult- ing. Gp. Occ- Group oc- culting. Alt. Oce.- Al- ternating oc- culting. A light totally eclipsed at regular intervals, the duration of light always equal to or greater than the duration of darkness. A light with a group of 2 or more eclipses at regular intervals. Light colors used and abbreviations: W —white, R—red, G-green. 12

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With all the variations in lighthouse structure, the one most familiar to the layman is the land masonry beacon, and it is no wonder that such lights as Mon- tauk, Tybee, Cape Hatteras, and the Old Sands Point Light have for years been a subject for artists. Con- structed on a solid foundation, the walls at the base are often greater than five feet thick, adding weight and strength where it is most needed. Sturdy and bold these lights are often subjected to the ceaseless erosion of the savage sea, resisting its every motion with all their might. “Safety is only to be found in certainty, and any- thing which does not secure the latter condition is a foe rather than a friend to the mariner,” is a slogan of Trinity House, the British Lighthouse Agency. An early report of the Lighthouse Board mentions: One maxim should ever be observed, namely, perfect regularity of exhibition of every signal from night to night and from year to year. A light, for example, which has been regularly visible from a tower, it may be for years, cannot be suffered to fail for a single hour, without danger of casualties of the most serious character. The approach to land is one of the most fascinating aspects of any ocean voyage. Having traversed thou- sands of miles of open seas, guided solely by the movements of the heavens and the wondrous elec- tronic marvels of our times, the navigator feels a sense of accomplishment upon first sighting his destination. As the lights of the land first bob and then finally settle upon the horizon, great care must be taken in selecting the proper lights to determine precisely the vessel’s position. The reliance the mariner places in the light demon- strating its own characteristic visual signals is without ST. GEORGE REEF: Taking over ten years to construct, St. George Light is one of the most expensive American lighthouses in existence. TYBEE LIGHTHOUSE: This masonry land situated structure is symbolic of all such similar lighthouses. Best known to lavmen, the land structure is one of the artist’s favorite subjects, Tybee Light being no exception. 11

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Measuring eight and one-half feet in diameter, it is large enough to easily accommodate three men. as % old Fresnel lens, imported from Paris and capable of producing a horizontal beam of 200,000 candlepower with a charted visibility of nineteen miles. The largest lens in the United States is of the hyper- radiant type and is located on Makapuu Point, Hawaii. Situated high above the cliffs of Oahu Island, Makapuu Point Light is passed by all commerce from the west coast of North America bound for Honolulu. So elephantine is the lens, having a diameter of eight and one-half feet, that it can easily accommodate three men. Impressive as it is, the lens used at Makapuu Point is obsolete, having been overshadowed by modern advances in optics and smaller lenses, such as those found in the aerial beacon of St. John’s Light at Mayport, Florida. Using two vertical mirror re- flectors, each containing a thousand watt light bulb, St. John’s Light can develop a 250,000 candlepower beam visible for fifteen miles. This is certainly an indication of the pace of the times. Every seafaring man knows the importance of adequate protection against the failure of any neces- sary piece of equipment on board his ship. The lack of proper standby equipment could, if the time ever called for it, prove fatal. So is the case with light- houses. A light must continue to burn showing all its proper characteristics under the worst possible conditions if it is to aid the mariner. The lighthouse at Montauk Point, typical of many lighthouses, has a unique device to meet just such an emergency. Montauk’s heavy lens rests on a metal disk floating atop a trough of mercury. The great density of mercury makes it suitable to support lenses weighing as much as seven tons, and enables a man to com- pletely rotate the lens by hand with little effort. Located directly below the trough is a small horizon- tal drum of steel cable attached to a heavy weight suspended along the inner wall of the structure. The drum is connected through reduction gears to the rotating disk upon which the lens rests. If the MONTAUK LENS: A variation of the famed Fresnel Lens, the lens at Montauk Lighthouse is capable of producing 200,000 candlepower using only a thousand watt bulb. ST. JOHN’S LIGHT: Modern technology has made possible the use of small lenses to achieve the same candlepower effectiveness as was once obtained using large, hard to handle lenses. This Coast Guardsman is inserting a new thousand watt bulb inside the lower mirror compartment of St. John’s Light. ' 13