steel. With the diver's hand holding the hacksaw, a 3/8 inch long cut 

 was made in the 1/2 inch plate after 3 minutes of cutting. 



Although the hydraulic hacksaw satisfactorily converts fluid power 

 to a reciprocating motion, when the hacksaw is operated as a hand tool 

 the diver cannot effectively load the blade. Another undersirable 

 feature is that the hacksaw reciprocates instead of the blade unless 

 it is forced against the steel plate being cut. The track (see Figure 

 28) designed to prevent the hacksaw from reciprocating, had the unde- 

 sirable effect of making it even more difficult for the diver to force 

 the blade into the work. This hacksaw is not suitable for use by 

 divers in its present configuration. It is possible that this hacksaw 

 can be adapted into a future cutting system where the diver is not re- 

 quired to hold the tool. 



SUMMARY 



Diver-Powered Equipment 



Underwater tests at NCEL have determined the feasibility of using 

 diver-powered hydraulic equipment for underwater salvage operations. 

 This hydraulic equipment is commercially available and requires only 

 nominal modifications and simple maintenance for reliable underwater 

 operation. However, it cannot be overemphasized that utilizing the 

 diver as a prime mover is justifiable only for small tasks and in 

 emergency situations. For repetitive underwater work tasks the diver 

 must be utilized as a tool operator and not as a prime mover. Using 

 the diver as the prime mover on a large task may tire him so that his 

 safety is jeopardized. 



A modified two-stage hydraulic pump was used to convert the diver's 

 energy to hydraulic power. With this type of pump, a diver can be ex- 

 pected to generate fluid power to operate small rams, hydraulic cylinders 

 and cutters. The hydraulic rams and cylinders are limited to approximate- 

 ly a two-inch internal diameter with a 10 to 12 inch stroke to keep the 

 pumping cycle less than five minutes and to permit easy diver handling 

 of the components. 



Open Center Equipment 



Three open center hydraulic salvage tools were evaluated - a cutter, 

 a power handle driven winch, and a hacksaw. None of these tools is 

 recommended for Navy use in its present form. The cutter promises to 

 be a very useful tool when the cutting mechanism is improved. It also 

 would be advantageous to reduce the tool weight. The "disposable" 

 winch and power handle concept appears to be promising for extensive 

 underwater salvage operations. The hydraulic hacksaw is not a satis- 

 factory diver tool in its present form. 



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