operation may be forgotten indefinitely tinder these conditions. 

 Finally, extreme effort eind expense may have gone into placing a 

 diver or vehicle on a work target iinder water. Under these cir- 

 cumstances, a tool must perform as expected. Cost effectiveness 

 parameters differ considerably between tools developed for use on 

 land, sind those developed for use under water. 



The operating limitations described above dictate three pri- 

 mary considerations in the performance of underwater tools, 

 safety, reliability and simplicity of operation. In response to 

 requirements for underwater tools, the Naval Ordnance Laboratory 

 (NOL), White Oak, hais placed these considerations first in every 

 design approach. Historically, propellant-driven actuators have 

 been proven safe, reliable, and simple to operate in main's normeil 

 environment. Moreover, for underwater applications, tools powered 

 by propellant-driven actuators appear to have a natural design 

 advantage. A propellant-drive actuator normally develops large 

 pressures within a tool when fired. Therefore, as a general rule, 

 these tools also will withstand considerable external hydrostatic 

 pressures . 



In light of these considerations, a family of first-generation, 

 propellant- actuated tools has emerged as the mainstay of the under- 

 water tools development effort at NOL. This paper documents that 

 effort, and in addition, touches on other allied projects includ- 

 ing an interesting and promising new approach in the development 

 of \inderwater tools. Each of the items described may be used on 

 land. Each is being considered for possible use with underwater 

 vehicle manipulators, although this has not been a design require- 

 ment to date. 



UNDERWATER TOOLS DEVELOPMENTS 



Primary support for the development of underwater tools at NOL 

 has come from three sources: Under Specific Operational Require- 

 ment 38-OI, the Swimmer Weapons System has produced the small 

 Driver Mk 22 Mod and the Cable Cutter Mk 20 Mod 0. Under the 

 combined support of the Deep Submergence Systems Project and the 

 Supervisor of Salvage, two additional stud drivers are being 

 developed for relatively heavy duty work. In addition, a Salvage- 

 Lift PADEYE is under development. 



DRIVER MK 22 MOD . The Driver Mk 22 Mod is shown in Figure 

 1. Ihis driver was designed for use in nailing light objects to 

 wood or thin steel plating. Prior to use, the driver is completely 

 sealed against water leakage. Therefore, when firing occurs, the 

 stud is able to build up maximum kinetic energy for penetration 

 of the target upon emerging through the barrel cap of the driver. 

 The stud is pushed along inside of the driver, from right to left 

 in Figure 1, by expanding gases from a burning propellant. The 

 propellant is ignited by triggering of a spring-loeided striker 



118 



