The ram presented no particular diver handling problems. However, 

 the threaded extensions were difficult to start. Divers typically have 

 problems aligning threaded fittings underwater and this is compounded 

 if there is poor visibility. The threads on the ram accessories were 

 coated with a commercial non-seizing compound to prevent corrosion. 

 The non-seizing compound was messy for the divers to handle but did an 

 excellent job of preventing corrosion. The divers were able to assemble 

 and disassemble the threaded connections by hand throughout the test 

 program. The hand-tightened threads did not deform under the 4-1/2 ton 

 loads, and the extensions usually could be disassembled by the divers 

 in the water. 



Several problems were encountered using the pinned connectors. The 

 connectors had to be inserted the correct distance and rotated properly 

 before the pin could be inserted. The pins are relatively easy to lose 

 and hard to find in a tool box or tool bag. The pins also occasionally 

 jammed after a heavy load had been applied and it was often impossible 

 for the divers to disassemble the connections underwater because of 

 bent pins and jammed inserts. 



The following design changes are recommended to reduce the described 

 problems : 



1. Redesign the extensions as shown in Figure 17a. This would 

 permit the load to be borne entirely by the shoulders of the pin connec- 

 tion insert. The retainer pins should be chained to the extension pipe, 

 and the clearance between the retainer pin, the connection pin, and the 

 extension pipe should be adequate to permit very easy insertion and 

 removal . 



2. An alternate method of extending ram length was suggested by 

 one of the divers and is shown in Figure 17b. 



All components of these extension systems must be of sufficient 

 strength and corrosion resistance to prevent jamming from application of 

 heavy loads or from corrosion. 



The rams used as jacks are susceptible to seawater corrosion because 

 water is drawn into the evacuated space between the piston and the hous- 

 ing on the return stroke (see Figure 18). During the next ram extension 

 some of this water may leak past the pressure seal into the hydraulic 

 fluid. This leakage can be tolerated if a corrosion-inhibited hydraulic 

 fluid is used. However, corrosion begins if the ram is stored with 

 salt water between the piston and the housing. The water eventually 

 corrodes the housing so that the pressure seal leaks during extensions 

 and the corrosion can become so severe that the piston is frozen to the 

 housing. Corrosion can be reduced by storing the ram with the piston 

 extended so that the housing interior is covered with hydraulic fluid. 

 The rams at NCEL were in a satisfactory condition after the three-month 

 test program even though they were submerged for several one-week periods. 

 Whenever they were not being used, they were stored with the rod extended. 



In addition to the ram used for jacking, double-acting hydraulic 

 cylinders were evaluated as a method of pulling loads. The extended 

 double-acting cylinder with hooks in Figure 11 has an overall extended 



18 



