Figvre 6-9. Lowering and retrieving the Ewing piston corer. 



the contents of the cutting edge and core 

 catcher are not retained. 



Remove the cutting edge and core catcher 

 from the trigger-weight corer. Insert a rubber 

 stopper into the bottom of the Hner and remove 

 the liner from the tube. If the liner is not com- 

 pletely filled with sediment, fill the empty 

 portion with glass wool. Insert a rubber 

 stopper in the top of the liner, tape both ends, 

 and seal with wax. Label the liner and store 

 in an upright position. 



Measure the length of sediment visible on the 

 outside of the Ewing coring tube and record this 

 in the Penetration column of the M-sheet. 

 Next, unbolt the cutting edge and remove it 

 and the core catcher. Carefully remove any 

 sediment retained by these pieces and place in a 

 sample jar. Label the sample. Place a metal 

 cap over the end of the coring tube and secm-e it 

 tightly with waterproof tape. Using paint, 

 mark the cap "Bottom". 



Remove all the bolts that hold the coring 

 tube in the connector sleeve of the mainweight. 

 Withdraw the coring tube until it is free of the 

 mainweight and piston. Sound the tube with a 

 rod and measure the length of the core. Record 

 the length on oceanographic log sheet M. Pack 

 the unsupported end of the sediment with a 

 good wad of clean rags. If the sediment is not 

 near the end of the tube, a well-packed wad of a 

 foot to a foot and a half thick should hold. 



H. O. 607 



Place a metal cap over the upper end and tape 

 securely. Using paint, mark the cap "Top". 

 With paint, record on the coring tube the ship, 

 cruise, core number, station number, date, and 

 position. Record this information also on the 

 log sheet together with a description of the core. 



6-52 Securing the Corer. — After each lower- 

 ing, the cutting edge, core catcher, and piston 

 must be washed and rinsed carefully to remove 

 all evidence of bottom material. All sediment 

 must be removed from the mainweight. The 

 filled coring tubes should be secured in racks 

 and the mainweight securely lashed in a cradle. 



6-53 Maintenance of the Ewing Piston 

 Corer. — Owing to its stiu-dy construction, the 

 corer generally requires little mamtenance. 

 However, the cutting edge may be chipped or 

 bent from striking hard or rocky bottom. If 

 not too badly damaged, the cutting edge may 

 be hammered and filed back into shape. 



Bent coring tubes usually result from partial 

 penetration into the sea floor rather than from 

 contact with a hard bottom. On striking a 

 hard bottom, the cutting edge may be damaged 

 and the corer topples over without bending the 

 tube. When penetration is stopped at about 10 

 feet or so by striking firmer sediment, the part 

 of the coring tube in the sediment is held 

 upright whUe the remaining portion falls over 

 of its own weight. In such cases, minor bends 



65 



