The data and experience gained with the commercial hydraulic salvage 

 equipment will then be used to design and fabricate improved hydraulic 

 salvage equipment for divers, as well as for operation from submersibles. 

 The high cost of developing a new hydraulic tool makes it imperative 

 that the requirement for the tool be firmly established and that valid 

 design data be available. Satisfactory design data can usually be 

 generated with underwater tests of either modified commercially available 

 tools or bread-board type tools built from existing components. This 

 report is one of three that will present underwater test results and 

 evaluate commercially available and bread-board type hydraulic salvage 

 equipment. Additional reports are planned on hydraulic power sources 

 and abrasive cutting. Open center hydraulic tools are preferred for 

 underwater operations because the hydraulic fluid circulates through 

 the hoses at all times reducing the undesirable increase in fluid 

 viscosity when the hoses are in cold water. Hydraulic power sources 

 driven by diesel engines or electric motors are available to operate 

 open center hydraulic tools and equipment. However, most of the commer- 

 cially available hydraulic cutting, rigging and load handling equipment 

 utilize single acting (rams) or double acting hydraulic cylinders which 

 are not an open center configuration but require small volumes (<30 in ) 

 of fluid at high pressures (2000 to 6000 psi). Simple diver powered 

 pumps were evaluated by NCEL as an alternative to providing a separate, 

 complex and expensive hydraulic power source for the salvage equipment 

 based on hydraulic rams and cylinders. 



TEST FACILITIES AND EQUIPMENT 



The hydraulic salvage equipment selected for testing was operated 

 by the Navy personnel assigned to NCEL's Diving Locker and by NCEL 

 diving engineers, including the senior author. The hydraulic tools and 

 equipment were used both in the diving tank at the NCEL Diving Locker 

 and in 60 feet of water at Anacapa Island off the Southern California 

 coast. Most of the diving was done in wet suits with either a Navy 

 shallow water mask or the Kirby-Morgan band mask. This diving equipment 

 was used because of its similarity to the diving dress worn by divers 

 working out of a bell system (e.g., Mark I DDS). Some tool evaluation 

 diving was also done in deep sea dress (Mark V) and with scuba gear. 



The Navy T6B pontoon in Figures 1 and 2 was modified for use as a 

 test stand. Attached to the sides of the pontoon were lifting brackets, 

 frames for holding wire rope and bar stock, frames for tensioning wire 

 rope slings, a hydraulic hacksaw track, and a load cell. The load cell 

 is shown schematically in Figure 3. It was welded to the top of the 

 pontoon and provided an essentially constant (<107„ variation) load 

 throughout a 10-inch stroke. This load cell was used for the hydraulic 

 ram and pull cylinder tests. The force required to move the load cell 

 cylinder rod was variable by changing the air pressure in the storage 

 bottles. The maximum working load was 4-1/2 tons (9000 pounds) because 

 of load cell frame deflection. 



