FULL 

 PENETRATION 



FREE FALL 



PARTIAL 



PENETRATION 



SEA BOTTOM 



CORE LINER 

 RELEASING 



FROM BALLAST 

 ASSEMBLY 



FLOAT 



ASSEMBLY 



HAULING CORE 



TO SURFACE 



feJ 



Figure L-28. Principle of operation of Boomerang gravity-type corer. 



sphere. If the flash rate is below the 2- to 3-sec- 

 ond nominal rate or if the flash assembly has 

 been in operation for 16 hours, replace the bat- 

 tery. If the battery is to be replaced, proceed to 

 steps 2, 3, and 4; otherwise go to step 5. 



Step 2. Remove the glass spheres from the 

 nylon net bag and place tlie flashing sphere in 

 the sphere stand. With a screwdriver, remove 

 the two liose clamps from the flashing sphere 

 and disassemble. Tape magnetic switch in place 

 when hose clamps are removed. 



NOTE: A lower air pressure inside the 

 sphere may make it necessary to slide the hemi- 

 splieres apart by tightening one of the clamps as 

 shown in figure L-29a. Care should be taken to 

 avoid scratching or chipping the sealing 

 surfaces of the two halves of the sphere (fig. 



L-24 



L-29b). Replace battery with a 240V Burgess 

 U-160 or Eveready 491, and check flashing cir- 

 cuit by removing magnetic switch. Mark "OLD" 

 in several places on the used battery. 



Step 3. Reassemble the flashing sphere, tak- 

 ing extreme care to clean the sealing surfaces, to 

 coat them with a thin layer of silicone gasket 

 grease, and to line up the match marks of the 

 two halves as they are assembled. Any air in the 

 joint will appear as a white area and should be 

 eliminated by rotating or sliding the hemi- 

 spheres. Replace clamps and tigliten them down 

 firmly as shown in figure L-29 (c). 



Step 4. To reassemble the glass spheres in the 

 nylon net bag as shown in figure L-27, first 

 place the 10-inch fused-glass sphere in the bag. 

 Next place the PVC spacer ring on the sphere. 



Change 1—1970 



