may be straightened, but usually the core tube 

 is beyond repair. 



Core-catcher springs should be examined for 

 free play of action. Inasmuch as the spring 

 leaves are delicate, care must be taken in 

 handling and packing for shipment. 



If cores are extruded into core boxes instead 

 of being stored in the tubes, the tubes may be 

 used again. After extruding, while the sediment 

 is still damp, the inner walls of the tube must 

 be washed thoroughly to remove all traces from 

 the previous core, and a coating of light oil 

 applied. 



6-54 Extruding Ewing Cores. — When it is 

 desired to take additional cores for which there 

 are no coring tubes, the cores already obtained 

 may be extruded into a core box. The wooden 

 core box has partitions running the long way 

 of the box in which sections of the core are 

 placed. The sections must be wrapped in 

 waterproof paper. 



An extruding rod is made from a length of 

 pipe having a diameter slightly smaller than 

 the inside diameter of the coring tube. A 

 piston is bolted to the end of the pipe. The 

 pipe should be equal to or slightly longer than 

 the coring tube. 



Bolt or tape the coupling holes at the ends 

 of the coring tube to keep the sediment from 

 coming through during extrusion. The coring 

 tube with the core to be extruded is placed on 

 deck and the piston inserted into the bottom 

 end of the tube. A core is never extruded from 

 the top. The top part of the coring tube is lined 

 up with a core box. The end of the extruding 

 rod opposite the piston is placed against any 

 rigid stationary object. A line is secured about 

 the coring tube and taken to the gipsy head 

 of a winch. When a strain is taken, the line 

 pulls the coring tube while the core remains 

 stationary. The top end of the coring tube 

 should be held so the core will be laid into a 

 section of the core box with minimum disturb- 

 ance. Figure 6-10 illustrates the method for 

 arranging the waterproof paper in each section 

 of the box and placing the core. It is important 

 that the edge of the waterproof paper be kept 

 free of the core. If this is not done, the folds 

 will cut into the core and distiu-b it when the 

 core is wrapped. The free edge of the paper is 

 folded over and stapled to the side of the 

 partition. If the core is shorter than the box, a 

 block of wood is placed against the end of the 

 core and the waterproof paper stapled to it. 



Each length of the core must be marked 

 carefully to show the cruise and core number 

 and the top and bottom of the core. A dia- 



gram of the contents of each box must be 

 drawn in the coring log. 



6-55 Storing and Shipping Ewing Cores. — 



Because of the length of Ewing coring tubes 

 and core boxes, it is necessary to store them in 

 a horizontal position. When shipping, they 

 must be marked "Handle With Care" and the 

 covers marked "This Side Up". Trigger- 

 weight cores must be shipped in an upright 

 position and similarly marked. Cutting-edge 

 and core-catcher samples should be shipped in 

 a wooden box. All boxes should have the 

 ship's name and the cruise number placed on it. 

 Cases and coring tubes to be shipped to the 

 Hydrographic Office are to be addressed as 

 follows: 



The Hydrographer 



U. S. Navy Hydrographic Office 



Washington 25, D. C. 



Attn: Code 5430. 

 6-56 BOTTOM SIGNALING DEVICE, 

 THE BALL BREAKER.— Coring and sampling 

 activities in deep-sea areas present the problem 

 of determining the moment of contact of the 

 instrument with the bottom. A bottom signal- 

 ing device, or ball breaker, has been developed 

 and is employed aboard Navy survey ships. 



In shallow waters, a satisfactory method for 

 determining when the bottom has been reached 

 is the spring scale and block assembly described 

 in section 6-18. In deep waters, the weight of 

 the coring apparatus is often a small part of 

 the total weight of the wire out and of the 

 variable loads caused by the ship's rolling; 

 hence, no apparent drop in tension may be 

 observed on the scale when the bottom is 

 reached. Therefore, it is necessary to employ 

 an instrument which is independent of the 

 ratio of corer to total wire weight, rolling of 

 the ship, and depth of water. To meet this 

 need the ball breaker, which implodes a Sc- 

 inch glass ball when the bottom is reached, was 

 designed. The resulting implosion may be 

 heard on some types of echo sounders or re- 

 ceived on a Brush recorder wired to the echo 

 sounder. Another method of receiving the 

 implosion signal is to use a Brush, or similar, 

 recorder and amplifier with a hydrophone. 



6-57 Assembling the Bali Brealcer.— The 

 device is easy to assemble for lowering. Raise 

 the weighted piston to the top of the .frame and 

 hook in place with the trigger. Insert the 

 safety pin into the trigger until ready for lowering. 

 Secure a glass ball with tape so it is resting on 

 the three points at the bottom of the frame. 

 For most bottom sampling instruments, the 

 ball breaker is attached to the wire above the 

 instrument as shown in figure 6-11. When 



66 



H. O. 607 



