pump a distance of approximately 2,000 m (capacity of 1 16 m 3 /hr and extrapolating a d 50 =0.4 

 mm from Figure 27), then one booster pump will be required to pump the material the remaining 

 distance of 1,400 m (Appendix F). 



The second scenario involves deploying the Punaise onto the ebb shoal from the downdrift 

 beach along the 6. 1-m contour with the shore station located on the downdrift beach. This total 

 pumping distance is approximately 2,600 m (Figure 28). Assuming the Punaise PN400 can 

 pump a distance of 2,000 m, then one booster pump will be required to pump the remaining 

 600 m (Appendix F). (Pumping distances of the Punaise PN400 are preliminary and may be 

 extended with modifications to the system. Specifics about pumping distances and system 

 operation should be addressed to PinPoint Dredging Company, Inc. , on a case-specific basis.) 



A Punaise demonstration was planned for Shinnecock Inlet in January 1997. Total costs 

 were estimated at $8 10,000 to pump 153,000 m 3 (200,000 yd 3 ) of sand. Of this amount, 

 approximately $250,000 was for mob/demob, with the remaining $560,000 for operation. The 

 total unit cost for the demonstration project was to be $5.29/m 3 ($4.05/yd 3 ) or $3.66/m 3 

 ($2.80/yd 3 ) for operations. 1 PinPoint Dredging Company, Inc. 2 estimated an operational unit cost 

 of $2.80/yd 3 for a sand of d 50 =0.3 mm pumped a distance of approximately 2,000 m. Including a 

 booster station pushes the cost up to $3.30/yd 3 . Using these costs with booster pump costs used 

 in Alternative 2: Semi-fixed, bypassing costs (Tables 20 and 21) for both scenarios can be 

 estimated. Only lease/rental of the Punaise alternative is presented because PinPoint Dredging 

 Company, Inc., has no plans to market the Punaise system for sales. 



The demonstration project at Shinnecock Inlet was canceled in early January 1997, because a 

 clay layer was discovered at the borrow site that was too close to the seafloor surface. This 

 limited thickness of sand would prevent an efficient use of the Punaise in its current design at 

 this particular borrow site. PinPoint Dredging Company is investigating a design modification 

 that would make the Punaise more suitable for shallower water depths and/or thinner layers of 

 sand. For the Punaise to be considered for use at Shinnecock Inlet, a thorough geophysical 

 survey should be conducted to conclusively identify any potential borrow site where clay either 

 runs deeper or does not exist to ensure sufficient sand layer thickness. 



Personal communication, Mr. Fred Anders, New York State Department of State, Albany, NY, 1996. 



Personal communication, Mr. Kris Visser, PinPoint Dredging Company, Inc., (subsidiary of J.G. Nelis Group), Haarlem, The 

 Netherlands, 1996. 



66 Chapter 5 Other Bypassing Studies 



