TETHER LINE 



Figure L-32. 



Valve/release mechanism tube installed 

 on liner. 



into the core barrel until the liner release rod on 

 the valve/release mechanism tube reaches the 

 top of the barrel (fig. L-31). Then, push the 

 rod inward against its spring, and slide the liner 

 into the barrel until the catcher lip rests on the 

 flange inside the nose piece. 



Step 12. As the valve/i-elease mechanism tube 

 enters the core barrel, orient the liner release rod 

 so that it is in line with the spiral row of holes 

 in the barrel (fig. L-33). 



SPIRAL ROW OF HOLES 



Figure L-33. Ballast component in cradle. 



Step 13. Check that the catcher lip is seated 

 against the flange inside the nose piece, and then 

 with the tubular tool twist the liner and valve/ 

 release mechanism until the release lever rod 

 seats itself in one of the holes in the spiral row 

 of holes in the barrel. 



NOTE : Since the length of the core liner 

 increases about .008 inch for every degree centi- 

 grade increase in temperature and since each 

 hole in the spiral is .062 inch higher or lower 



L-26 



than the previous hole, it is better to wait until 

 just before launching the corer to seat the liner 

 release rod. In addition, when seating the liner 

 release rod, consideration should be given to the 

 differences between air and bottom water 

 temperatures. 



L-44 Obtaining the Boomerang Core. — 



After the float component has been checked and 

 the liner has been inserted in the ballast compo- 

 nent, the corer is ready for final preparation 

 prior to launching. 



Step 1. Fasten the free end of the 6-foot 

 tether line from the valve/release mechanism 

 of the liner to the nylon net bag of the float. 

 Make the tie on the bottom side of the flashing 

 sphere so that the flashing component will float 

 in an upright position. Mouse the knot to guard 

 against untying. NOTE : Wet nylon is very 

 slippery. 



Step 2. Seat the liner release lever rod, place 

 the net bag containing the spheres in the float 

 retaining shell, fused sphere first, and hook the 

 metal ring over the hook on the float release 

 ann. 



Step 3. Slide the pilot weight down to the 

 nose piece of the core barrel. This should draw 

 the float release wire tight, and the float release 

 arm should be held down against the ballast 

 weight. 



Step 4. Press the hollow rubber ball into the 

 hole in the float retaining shell to hold the float 

 release arm in place during launching. 



Step 5. Remove the magnetic switch, note the 

 time, and then with a line through the lowering 

 ring hoist the Boomerang corer over the side. 



Step 6. When on station, drop the corer, and 

 again note the time. At a depth of about 10 

 meters, the air in the hollow rubber ball will 

 become compressed, and the ball will float free 

 and return to the surface. Retrieve it with a net. 



L-45 Retrieving the Boomerang Corer. — 



Since retrieving the Boomerang corer is very 

 difficult even under ideal conditions, the follow- 

 ing precautions should be taken to avoid losing 

 or damaging the float component and/or the 

 core during retrieval : 



Step 1. Obtain a depth measurement for the 

 station, determine the approximate time the 

 float component should surface, and standby to 

 watch for the float. NOTE: The corer will de- 

 scend at approximately 450 meters per minute, 

 and the float component will rise at approxi- 

 mately 75 meters per minute. The float com- 

 ponent is difficult to sight during daylight 

 hours; therefore, if possible, schedule Boome- 

 rang corer operations during hours of darkness. 

 If the ocean bottom is too hard and the corer 

 fails to penetrate enough to release the float 

 component or if the ballixst component falls 

 over on its side, the float component and core 

 liner will be lost. 



Change 1—1970 



