V. PROCEDURAL MODIFICATIONS 



Coring procedures that provide increased flexibility may be used when 

 short cores (< 10 feet) are sufficient, and weight and space limitations exist 

 for transporting the coring equipment. In this case the entire tripod with 

 the extra extension shaft is not needed; only the vibrating system, the pipe, 

 one come-along, a gas-main sealer plug, and packaging materials are necessary, 

 all of which can be transported by helicopter, small plane, or small boat. 

 The cores are intruded and packaged as previously discussed. Extraction is 

 sim.plified by using a 2- by 4-inch (5.1 by 10.2 centimeters) piece of sturdy 

 wood, 6 feet (1.8 meters) long, or an extra piece of pipe in place of the tri- 

 pod, as a bracing for the come-along. One hook of the come-along is attached 

 to a rope securely tied to the core pipe, the other hook is fastened to the 

 top of the makeshift support. One individual is sufficient to keep the support 

 stable while another jacks the core out of the sediment (Fig, 7). 



•'i^. 



vl;*^ 



Figure 7. The modified corinp procedure for 

 collecting short cores. 



VI. FIELD TESTS 



During the summer of 1980, 35 cores, ranging from 13 to 33 feet long, were 

 recovered along the coast of Virginia during a 3-week period. Later that year, 

 nine additional cores, each 10 feet long, were recovered in 1 day by the modi- 

 fied coring method and transported to CERC by helicopter. No problems occurred 

 during either field test. 



14 



