PART Hi 



TIDES AND TIDAL CURRENTS 



The Woods Hole Oce anograph i c iNSTixurioN has esti- 

 mated THAT THE MAXIMUM ASTRONOMICAL TIDES AT 



George's Bank and Nantucket Shoals will be in the 



ORDER of 2 FEET ABOVE AND BELOW MAIN SEA LEVEL. 



This estimate has been confirmed exactly by tide 



CYCLE measurements MADE FROM THE FIXED PLATFORM 



of the drill barge during boring operations at these 

 locations. It is possible that the astronomical 



TIDE MAY BE SOMEWHAT GREATER AT CASHES LEOGE AND 

 SOMEWHAT LESS AT BROWN'S BaNK AND THE LOCATION OFF 



New York. The charts of Georges Bank and Nantucket 

 Shoals show tidal currents up to velocities of 5 

 knots per hour varying in all directions with the 

 stage of the tide. Observations during the drilling 

 operations confirmed these tidal currents which 

 maintained almost constant velocity although shift- 

 ing IN direction over the tidal cycle. Both the 

 charts and observations during the drilling opera- 

 tions show heavy tidal rips over or near the shallow- 

 est portions of the shoal areas. Further, the Woods 

 Hole geologists who investigated the bottom condi- 

 tions IN THESE areas BY SKIN DIVING, REPORT THAT THE 

 FIVE TO TEN FEET OF WATER IMMEDIATELY ABOVE SEA 

 BOTTOM IS FULL OF SWIRLING SAND "RESEMBLING A DRIV- 

 ING SNOW storm". This swirling sand is moved and 

 held in suspension 'by the ttoal currents. the woods 

 Hole Oceanograph i c Institution has estimated that 

 meteorological tides may amount to as much as 6 feet 

 and that they are likely to coincide with severe 



STORMS . 



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