becomes dented or chipped or core catcher 

 springs become damaged, replace the part. If 

 piston leather cup washer becomes worn, put a 

 new washer on the piston. After completion of 

 the operation, the corer (especially set screws 

 and movable fittings) should be rinsed with 

 fresh water, dried, and oiled lightly. Store the 

 equipment in the shipping cases. 



L-16 The Ewing Piston Corer.— The Ewing 

 Piston corer is designed for use where longer 

 cores are desired. It is the largest corer in use by 

 the U.S. Naval Oceanographic Office, and sev- 

 eral modified versions of the corer have been 

 built that weigh up to 2,000 pounds. Because of 

 their weight and size, Ewing piston corers are 

 operationally limited to ships equipped with a 

 large winch carrying at least %-inch wire, a 

 boom or crane capable of supporting the corer, 

 and sufficient deck space to assemble the corer. 



The Ewing corer (2,000 pound) assembly 

 consists of the following components (Fig. 

 L-7): 



The mainweight whicli includes the mam 

 body tube, the tailfin assembly, bail, ring, and 

 20 shaped cast lead drive weights. The overall 

 length of the mainweight is about 5 feet ; 



The coring tubes, which are seamless steel 

 tubing 2%-inch outside diameter and 2l^-inch 

 inside diameter, are 20 feet long. Each end of 

 the tube is drilled and ta.pped to take stainless 

 steel setscrews; 



Coring tube connector sleeves ; 



A piston with three leather washers and a 

 check valve ; 



A piston stop collar ; 



A core catcher ; 



A cutting edge ; 



A tripping release mechanism and trigger 

 line; 



A 250- to 300-pound trigger weight, consist- 

 ing of a coring device such as the Kullenberg 

 piston corer rigged as a gravity corer (see par. 

 1-12); 



Plastic liner in 20- foot lengths with caps ; 



Miscellaneous spare parts. 



L-17 Instructions for Assembling and Op- 

 erating the Ewing Piston Corer. — The fol- 

 lowing tools are needed to assemble and operate 

 the Ewing piston corer : 



Pliers, 8-inch combination ; 



Screwdriver, medium ; 



Screwdriver, large; 



TAILFIN 

 ASSEMBLY 



CUTTING 

 EDGE 



LINER \^ \ / / LINER 



CORING TUBES 

 Figure L-7. The Ewing corer (2,000 pound) assembly. 



L-8 



