Step 1. When the release mechanism has sur- 

 faced, rig in the boom or crane and bring the 

 gear to deck working level. Hoist aboard the 

 trigger weiglit corer and detach the release 

 mechanism from the wire. 



Step 2. Next, bring the mainweight to deck 

 working level and insert the swivel hook into 

 the lifting ring or sling. Take a strain with the 

 hook and slack the lowering cable to raise the 

 coring tube to a near horizontal position. Sup- 

 port the coring tube with liandling lines, bring 

 the corer inboard, and lower it into a cradle to 

 prevent it rolling on the deck. 



L-20 Removing, Logging, and Labeling the 

 Ewing Core. — The trigger-weight corer takes 

 a sample which is of great importance in deter- 

 mining the surface sediment of the ocean floor. 

 This cannot be determined from the top of the 

 main core because that part usually is unconsoli- 

 dated owing to piston action. The contents of 

 the cutting edge and core catcher of the main 

 coring tube also are of great importance; they 

 represent the material found at the deepest 

 penetration. 



Step 1. Remove the trigger- weight core. 



Step 2. Measure the length of sediment on the 

 outside of the Ewing coring tube. Retain this 

 measurement for step 6 below. 



Step 3. Remove the screws that connect the 

 cutting edge to the coring tube, and remove the 

 cutting edge and the core cutter. Carefully re- 

 move any. sediment retained by these pieces and 

 place it in a sample jar. 



Step 4. Remove the screws from the connec- 

 tor sleeve on the other end of this section of 

 coring tube to disconnect it from the balance of 

 the corer; then, extrude a few inches of the 

 liner out of the bottom of the tube, and cap the 

 bottom of the liner and seal it with adhesive 

 and/or tape. 



Step 5. Slide the liner the rest of the way out 

 of the coi-ing tube, and if the liner is full of 

 sediment, cap and seal it. If the liner is only 

 partially full of sediment, sound the liner to 

 measure the length of the core, and with a saw, 

 make a cut an inch or so above the top of the 

 core to drain off excess water; then, cut off the 

 liner and cap and seal it. Be sure to mark liner 

 so top and bottom are not confused. 



Step 6. 'Wlien all liners are capped and sealed, 

 log the samples (Ewing liners, trigger- weight 

 core, and sample jar) on the Oceanographic Log 

 Sheet-M. For instructions see paragraph L-39, 

 Oceanographic Log Sheet-M Bottom Sediment 

 Data. 



Step 7. Label the samples according to in- 

 structions given in paragraph L-40, Labeling 

 the Bottom Sediment Sample (s). 



Step 8. If trigger-weight core liner is CAB 

 plastic, coat with wax according to instructions 

 in paragraph L-30, Applying Wax to Core 

 Sample Liners. 



L-10 



L-21 Packing, Storing, and Shipping Ewing 

 Cores. — Trigger-weight cores and sample jars 

 are packed, stored, and shij^ped in accordance 

 with instructions in paragraph Lr-41, Packing, 

 Storing, and Shipping Bottom Sediment Sam- 

 ples; however, because of the size and weight 

 of Ewing coring tubes, they are stored and 

 shipped in a horizontal position. 



L-22 Maintenance of the Ewing Corer. — 



Owing to its sturdy construction, the Ewing 

 corer generally requires little maintenance; 

 however, when the corer attains only partial 

 penetration, the remaining portion of the core 

 may fall over of its own weight and bend the 

 coring tube beyond repair. In addition, cutting 

 edges are often damaged by striking hard or 

 rocky bottom, but they can be hammered or 

 filed back into, shape or replaced. After a coring 

 operation is completed, wash down all parts, 

 and lightly grease all threaded surfaces. 



L-23 The Hydro-Plastic (PVC) Piston 

 Corer.— The Hydro-Plastic (PVC) jpiston 

 corer is a special purpose corer designed by the 

 U.S. Naval Oceanographic Office to obtain semi- 

 undisturbed core samples. The corer utilizes a 

 high-impact grade of polyvinyl chloride (PVC) 

 plastic for the coring barrel or tube. This 

 lighter coring tube has several advantages. It 

 collects a larger diameter core sample; it has 

 a high retention of sediment interstitial water 

 during storage, good sediment penetration, and 

 it can be sectioned easily for sediment engineer- 

 ing projjerty analysis. The PVC corer is widely 

 used both as a piston and as a gravity corer, 

 and it can be lowered with the oceanographic 

 winch using %2- or ^/i6"inch wire. 



The Hydro-Plastic piston corer consists of 

 the following components (fig. Lf-9) : 



Weight stand assembly including the main 

 body tube, tailfin, bail, weight collar, and six 

 cast lead weights (50 pounds each) ; 



Plastic coring tube ( PVC ) available in ran- 

 dom lengths up to 20 feet, plastic caps for the 

 coring tube, and adhesive for sealing caps on 

 tube; 



Piston assembly; 



Core catcher; 



Cutting edge; 



Drill jig; 



Wire tripping release mechanism (same as 

 for Kullenberg corer) ; 



Trigger weight and trigger line; 



Spare parts, bolts, and shipping cases. 



L-24 Instructions for Assembling and Op- 

 erating the Hydro-Plastic (PVC) Corer.— 



The following tools are needed to assemble and 

 operate the Hydro-Plastic corer. 



Pliers, 8-inch combination ; 



Screwdriver ; 



Socket wrench set with ratchet handle; 



