(j) Sand Movement Study at Moriches Inlet, Long Island, New York 



A study of sand movement througn an inlet and along the adjacent 

 shore based on previously collected field data is underway. 



(k) Reexamination of Artificial Fill Projects 



Continuing program of reexamination of artificially nourished beaches 

 to determine the effectiveness of the fill material within the beach zones, 

 and to better establish the factors upon which to base the design 

 characteristics of fill material. Study of fill at Ocean City, New Jersey, 

 was reported on by Watts in T. M. #77. Reexamination is now underway 

 of projects at Virginia Beach, Virginia and Plum Island, Massachusetts. 



(1) Technical Report No. 4, "Shore Protection Planning and Design" 



i 



Continuing study to improve and supplement present chapters 

 of this publication. A report on "Factors Affecting the Economic Life 

 ofTimber in Coastal Structures"by Jachowski was published as T. M. #66. 

 General corrections and addenda to T.R. No. 4 have been completed and 

 will be disseminated when printed. 



(m) Regional Studies 



Data on the geomorphology and characteristics of littoral 

 materials were compiled for the Delaware coast. Similar material is 

 being gathered for the south shore of Long Island. 



XIV. New Equipment 



It may also be of interest to note that the prototype wave tank was 

 completed and put into operation in the Spring. The tank is of rein- 

 forced concrete, and is 635 feet long, 20 feet deep and 15 feet wide. 

 The wave-generating mechanism provided for the wave tank consists of a 

 vertical bulkhead 15 feet wide and 23 feet high, connected to a carriage. 

 The carriage moves back and forth on rails mounted on each wall of the 

 tank. Top rails are also required to prevent lifting of the carriage 

 from the rails during operation. The back and forth motion is trans- 

 mitted to the bulkhead and carriage by two arms, 43 feet-9 inches in 

 length, connected to two driving discs. Each disc is 19 feet in diameter 

 and weighs 14 tons. The discs are driven through a train of gears by 

 a 510-horsepower, 2,300-volt synchronous motor. The motor has a con- 

 stant speed of 1,200 revolutions per minute. Four interchangeable 

 pairs of gears are provided to permit variations in the speed of the 

 discs. The alternate gearing will allow wave periods of approximately 

 5.60, 7.87, 11.32, and 16.01 seconds. The lengths o^ stroke of the 

 bulkhead movement can be varied from 2 feet to 17 feet-6 inches by chang- 

 ing the eccentric setting of the connecting arms on the driving discs. 

 The stroke setting may be varied in 3-inch increments through the range 

 from 2 to 8 feet and in 6-inch increments from 8 feet to 17 feet-6 inches. 



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