TM No. 377 



The Buzzards Bay Entrance Light Station ( BBELS ) was chosen as a platform 

 from which to make the open ocean wave measurements. This structure, a manned 

 light station maintained by the Coast Guard, is located at kl° 23.8' N and 

 71° 02..1' W — about 7 km WSW of Cuttyhunk Island and about 12 km south of 

 the Massachusetts coast. (See the reproduction of the Coast and Geodetic Survey 

 Chart No. 70 in figure IV-3.) The depth of water at 3BELS is about 20 meters . 

 The light station, shown in figure IV-4-, is a rigid steel platform supported 

 about 2k meters above the water by four steel legs which are driven some 63 

 meters into the sandy bottom. The top deck (the roof of the house), serves 

 as a helicopter landing pad. Because of the problems of transfer in the 

 prevailing swell conditions, personnel are usually transported to and from 

 the tower by helicopter in lieu of surface craft. 



The light station is located 25 km, or about a 15-minute helicopter flight, 

 from the Naval Underwater Weapons Research and Engineering Station at Newport, 

 Rhode Island (see figure IV-3). Fortunately, a Naval Air Torpedo Unit was 

 stationed at the Quonset Point Naval Air Station (located on the west side of 

 Narragansett Bay) and could provide helicopter service to and from the tower 

 for personnel and equipments 



As is shown in figure IV=4, the four main support legs (85 cm outside 

 diameter) are interconnected with smaller piping both above and below the 

 water line. The tower is thus a rigid structure, but at the same time offers 

 little gross drag resistance to currents. More important, it is quite trans- 

 parent to the trains of surface waves passing through the legs, particularly 

 when the wavelengths far surpass the diameter of the cylindrical legs, which 

 is most often the case. The station housing contains the aid-to-navigation 

 equipment, power generators, and living quarters for the men. With its inher- 

 ent stability, ample a-c power, winch equipment, and protected laboratory 

 facilities, the light station provides .an ideal platform for making a variety 

 of oceanographical and meteorological measurements . During certain periods 

 from 1962 to the present, both the Navy Oceanographic Office and the Coastal 

 Engineering Research Center (formerly the Beach Erosion Board) have maintained 

 various wave sensing probes for making observations throughout the year. Also, 

 station personnel make daily samplings of the surface water temperature and 

 salinity for the Woods Role Oceanographic Institution. 



Permanently installed in the tower laboratory is a bubble-type pressure 

 recording tide gauge maintained by the Coast and Geodetic Survey (C&GS). Since 

 the Coast Guard personnel aboard the BBELS keep a weather log much the same as 

 on a vessel, a large backlog of information is available regarding the general 

 meteorological environment Wind, sea., and swell data are logged on a four 

 hour basis,. The wind data are obtained with an anemometer system (maintained 

 by the Weather Bureau) mounted on the northeast corner of the main platform. 



The gross bottom topography and land boundary configurations in the viein° 

 ity of the BBELS are delineated in figure IV=3° Depths are given in fathoms 

 (about I083 m)., The 10, 20, 30 and kO fathom contours are depicted as broken 

 lines. As shown in the fisure.. there is an unobstructed or "infinite " wind 

 fetch of open ocean in the sector bounded 'by the azimuths lb0° and 250° T. To 

 the north and northwest; the fetch from the coast varies from 8-10 kmo 



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