number and the cruise name and number. 

 Cases to be shipped to the Hydrographic 

 Office should be addressed as follows: 



The Hydrographer 



U. S. Navy Hydrographic Office 



Washington 25, D. C. 



Attn: Code 5430 

 6-41 INSTRUCTIONS FOR OPERATING 

 THE EWING PISTON CORER.— The Ewing 

 piston corer is designed for use where bigger 

 and longer cores are desired than those obtain- 

 able by either the Phleger or Kullenberg corers. 

 It is employed when a detailed study of sedi- 

 ments below the surface of the ocean floor is 

 desired. It is the largest corer currently in use 

 by the Hydrographic Office, weighing about 

 1,200 pounds. The coring tubes are approxi- 

 mately 20 feet in length and 1, 2, or 3 lengths 

 may be coupled together by connecting sleeves 

 to obtain cores up to about 60 feet in length. 

 Unlike the Phleger and Kullenberg corers, the 

 Ewing does not use a plastic liner. Core 

 samples are stored in the coring tubes in which 

 they were obtained, or they are extruded onto 

 a heavy waxed paper provided for wrapping, 

 and stored in a wooden core box. 



6-42 Operational Limitations. — Due to its 

 size and weight, the Ewing piston corer is 

 operationally limited to ships equipped with a 

 large winch carrying wire of at least K-inch 

 diameter, a dynamometer, a boom or crane 

 capable of supporting about 5 tons, and 

 enough deck space to assemble the corer. 



6-43 Equipment Needed to Operate the 

 Ewing Piston Corer. — The corer itself consists 

 of the following parts: 



1. The mainweight, which is made up of a 

 main body tube, a tailfin assembly, and several 

 cast lead drive weights, usually 8 or 10 in 

 number. These leads weigh about 100 pounds 

 each and are secured above and below by heavy 

 steel disks which are bolted to the main body 

 tube. There is a bail and ring at the top of 

 the tailfin assembly for hooking into the release 

 mechanism. The overall length of the main- 

 weight is about 5 feet. 



2. The coring tube, which is a seamless steel 

 tubing of 2%-inch outside diameter and 2}^-inch 

 inside diameter, and 20 feet long. Each end 

 of the tube is drilled and tapped to take about 

 15 stainless steel bolts. Each end is covered 

 with a protective sheet-metal cap which is 

 used to retain the samples when stored in the 

 tube. 



In addition to the above, the following com- 

 ponents are needed to operate the corer: 



1. A piston, with a Fiege fitting for attaching 

 to the K-inch lowering wire. It is made of 



62 



brass and has four leather washers and a 

 check valve. The latter permits flow of water 

 upward through the tube during free fall of the 

 corer. 



2. A piston stop collar, which is movable 

 and is attached to the wire just back of the 

 piston. This U-slotted stainless steel collar 

 consists of two disks that are held together 

 with screws. It prevents the piston from 

 passing through the main body tube and sup- 

 ports the weight of the corer after free fall. 



3. A core catcher, whose interleaved springs 

 fit inside the lower end of the coring tube. 

 The collar of the core catcher fits flush with 

 the end of the tube and inside the cutting edge. 



4. A cutting edge, which holds the core 

 catcher in place and has a sharpened rim for 

 penetrating the bottom. It fits over the end of 

 the coring tube and is attached with several 

 stainless steel bolts. 



5. A connector sleeve, which fits over the 

 end of the coring tube and is used when at- 

 taching the coring tube to the mainweight and 

 when two lengths of tuoe are fastened together. 

 It is bolted to the tubing with stainless steel 

 bolts. 



6. Stainless-steel bolts, which are used to 

 attach the coring tubes, connector sleeves, and 

 nosepiece. These small bolts are specially 

 made and have shanks whose lengths are equal 

 to the thickness of the coring tube wall. They 

 must not protrude into the inside of the tube 

 so as to obstruct passage of the piston or dis- 

 turb the sediment structure. To assemble the 

 corer with a single length of tube, about 30 

 bolts are needed. 



7. A wire-clamp release mechanism, from 

 which the corer is suspended and which re- 

 leases it for free fall to the bottom. 



8. A trigger line, used to suspend the trigger 

 weight from the arm of the release mechanism. 

 Manila line strong enough to carry an 80-pound 

 trigger weight is needed. It must be long 

 enough to suspend the trigger weight 12 to 14 

 feet below the nosepiece on the coring tube. 



9. A trigger weight, suspended from the end 

 of the trigger line, which prevents the release 

 mechanism from dropping the corer until the 

 weight hits the bottom. As the piston action 

 of the big corer frequently disturbs the surface 

 layers of sediment, it is necessary to obtain 

 a small undisturbed sample. To do this the 

 trigger weight is made like a small Phleger 

 corer without a tailfin assembly. It consists of 

 a main tube with a cast lead drive weight of 

 approximately 50 pounds, a short coring tube, 

 plastic liner, core catcher, and cutting edge. 

 The liner, core catcher, and cutting edge are the 



H. O. 607 



