392 



SALVAGE TESTS 



ii was concluded that the collapsible pontoon has the potential of being a versatile and use- 

 ful salvage device. However, account should be taken of the difficulty experienced by divers in 

 handling this unit. Elimination of minor hardware discrepancies will make the ten-ton pontoon 

 a very useful item in the salvage inventory. 



Investigations into the optimum pontoon capacity should be initiated for representative sal- 

 vage operations. Clusters of pontoons could provide a lift capability which might be quickly 

 transported to any corner of the earth. Lift control could be provided by arranging balloons at 

 various depths. Problems associated with this concept should be investigated.* 



PNEUMATIC -POWER ZERO-REACTION HAND TOOLS 



To make a man-in-the-sea more effective, he must be provided with powered tools designed 

 for his capabilities and the environment which limits his normal surface abilities. 



Since no powered tools had been designed to fill this need, the Battelle Memorial Institute, 

 Columbus, Ohio, conducted preliminary underwater tests in a test pool and in a water-filled 

 gravel pit with commercial pneumatic zero -reaction production tools which were modified 

 specifically for diver use. The promising results of these tests led to the development of an 

 ocean-bottom experiment which was conducted by the aquanauts at Sealab II, at no expense to 

 the Navy. 



This experiment included the use of a "reactionless" impact wrench and related test stand 

 (Fig. 150). Also, a pneumatic hammer was modified to drive a coring device of simplified de- 

 sign into the ocean bottom. The impact wrench was used to drill and tap holes, run nuts and 

 bolts, and for hole-saw cutting. 



The modified tools, which were adaptations of tools designed for the surface, did not per- 

 form all of their functions as well underwater. This reduced performance capability had been 

 anticipated, and some of the causes are readily understandable; however, other aspects will 

 require further study. The initial operation of the tools was degraded'fcomewhat by two defec- 

 tive hose couplings. "*# 



The combined effects of depth, near-zero visibility, low temperature, and gas-flow noise in 

 the breathing apparatus masked the feedback of intelligence to the operator necessary to exert 

 proper control over lightly loaded functions such as thread tapping and drilling. The reaction, 

 vibration, and noise from the impact wrench was so slight that feedback could be felt only when 

 the tool was triggered initially for each function, as in final nut and bolt torque up, and while 

 hole-saw cutting. As an example, while drilling, the aquanaut could tell that the tool was work- 

 ing only by closely observing the metal cuttings produced. Perhaps the tools were too reaction- 

 less. Feedback intelligence of some type is clearly necessary. 



An interesting result of drilling underwater is that it was learned that center punching is 

 unnecessary for drills 3/8 in. or larger. With 1/4 in. and smaller drills, the same technique 

 could result in rapid wear of the drill tip. 



The pneumatic -hammer-driven bottom -coring device performed very satisfactorily. Four 

 cores were obtained around the base of the Sealab in less than six minutes. 



*BuShips has adopted this pontoon, with several improvements, as a Standard Emergency Ship 

 Salvage Material Pool item. The improved pontoon has the added feature of being sufficiently- 

 strong to permit tiering three high in a lift mode. 



■fBuShips, with BuDocks concurrence, has assigned the Naval Civil Engineering Laboratory, 

 Port Hueneme, California, as "lead lab" for the development of collapsible pontoons in support 

 of the DSSP project. NCEL has let an on-going contract with U.S. Rubber Company for the 

 adaptation of the larger commercial Sealdtanks (up to Z5 tons lift capacity) for use as salvage 

 pontoons. This project looks to the possible use of larger collapsible pontoons in place of the 

 current 80-ton structural submarine salvage pontoons. 



