each pull stroke (when the cylinder is returned to the extended position) , 

 This would eliminate the rerigging problem and allow an effective full 

 stroke . 



Double-acting hydraulic cylinders draw less water into the housing 

 per stroke than rams because the pressure seal is located where the piston 

 rod enters the housing. Unfortunately, even a modified double-acting 

 hydraulic cylinder with an exterior wiping seal will bring a very thin 

 film of water on piston rod into the cylinder . This unavoidable problem 

 can usually be controlled by using a corrosion-inhibited hydraulic fluid 

 and changing it periodically . 



Hydraulic Cutters 



The hydraulic wire rope cutter in Figures 19 and 20 cuts wire rope 

 to 1-1/8-inch diameter and weighs 20 pounds in water. It can be operated 

 by one diver because the cutting head arrangement holds the cutter on 

 the wire rope. Slippage of the cutter down a vertical or sloping wire 

 rope prior to cutting can be prevented by using a pair of vise grips. 

 The cutter is connected to a diver powered hydraulic pump. The use of 

 hydraulic hose permits operation of the pump as far as 100 feet from 

 the cutter. This is very desirable if a wire under tension is cut. 



This hydraulic cutter is sold for the production cutting of wire 

 rope and is normally supplied with hydraulic fluid from an electrically- 

 driven hydraulic power pack. 



The purpose in testing this hydraulic cutter was to determine the 

 performance of the cutter underwater using a diver powered pump and to 

 determine if the cutter could cut materials other than wire rope. Cutting 

 tests were performed in the diving tank. 



Performance data for the hydraulic cutter is shown in Table V. 

 The range of values and their mean are presented where applicable. 





Table V. 



Wire Rope Cutter Data 





Material Cut 



Number 



of 

 Tests 



Time to 



Rig Cutter 



(min. ) 



Cutting 



Time 



(min. ) 



Number 

 of Pump 

 Strokes 



Max imum 

 Hydraulic 

 Pressure 

 (psi) 



Mean 



Range 



Mean 



Range 



Mean Range 



1/2" Steel Wire 

 Rope 6x19 w/lWRC 



4 



0.5 



0.4-0.6 



0.5 



0.4-0.6 



29 27-30 



2000 



1" Steel Wire 

 Rope 6x19 w/IWRC 



4 



0.5 



0.5-0.7 



1.2 



0.8-1.9 



42 30-54 



3000 



Angle Iron 3/4x 

 3/4x1/8 



2 



0.5 



0.4-0.6 



1.0 



0.8-1.2 



40 40-41 



1800 



5/8" dia. Steel 

 Rebar 



2 



0.5 



0.4-0.6 



1.5 



1.1-1.9 



43 41-45 



6200 



1" dia. Marine 

 Communication 

 Cable w/Armor 

 Braid 



2 



0.5 



0.4-0.6 



1.2 



1.1-1.3 



40 38-45 



1800 



22 



