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Uss Chicago Submerged

Figure 2-6. Skid-mounted se aw ate r power source

2.2.4.2 Rotary Disk Tool. The rotary disk tool (Figure 2-7) provides grinding and cutting capability for metals, concrete, wood, cable, etc. This tool is constructed primarily of plastic material for a strong, lightweight tool that is resistant to corrosion and wear. The seawater exhausts in a fan spray pattern onto the back of the abrasive disk. The spray serves to reduce disk drag and to flush loose material away from the work surface. A disk guard covers the 7-inch abrasive cutting wheel to protect the diver from injury. A bayonet style handle allows rotation of the grinding head for adaptability to grinding or cutting tasks for both left- and right-handed divers.

2.2.4.3 Rotary Impact Tool. The rotary impact tool (Figure 2-8) can be configured with a 1-inch-square drive anvil used for tightening or loosening fasteners. It may also be equipped for a 5/8-inch quick change internal hex chuck for drilling in wood or metal. When drilling holes larger than 0.5 inch in metal, a hole saw is recommended over a twist bit because of tool impacting. The tool is capable of delivering up to 800 foot-pounds of torque so regulation of the torque is necessary to prevent damaging the work. The commercial impact mechanism is maintained in a sealed housing filled with a water-soluble oil for lubrication and cooling. The oil should be checked daily and flushed at the end of the mission.

Figure 2-7 Rotary disk tool being used to clean split pipe.

Jon Lindbergh Diver Chicago

Figure 2-8 Rotary impact tool with drill chuck adaptor.

2.2.4.4 Handsaw. The bandsaw (Figure 2-9) is designed for cutting metals and other materials. Seawater exhausts at the gear box and flows over the pulley drive chain to flush away debris. The pulley drive chain should be lubricated daily to maintain its condition. The blade pulleys are wrapped with friction material that allows the blade to slip if binding occurs. The blade is angled in the throat area to allow cuts up to 8 inches deep on materials up to 4.5 inches thick. A guard protects the blade when the saw is not in use.

2.2.4.5 Rock Drill. The rock drill combines bit rotation with high impact energy for drilling holes up to 2 inches in diameter in rock and coral. The tool accepts both twist bit and cross bit drill steels. Currently not released, development continues on improving the reliability of the impact mechanism. Tool weight and operating figures are not available at press time.

2.2.5 Electrical Tools

Electricity can be safely used underwater provided the divers are protected from

Figure 2-8 Rotary impact tool with drill chuck adaptor.

WARNING Surface-powered electrical tools must be Approved for Navy Use in accordance with NAVSEAINST 10560.2C.

Figure 2-9 Bandsaw being used to cut steel cable.

electrical shock hazards. Diver electrical safety can be achieved by using common sense, education, preventive maintenance, properly designed underwater electrical equipment, and using the safety equipment.

Appendix D provides a discussion of electrical safety for divers and should be reviewed when electrical equipment is to be used on the underwater construction site.

Underwater tools and equipment that use electrical power are available for use with divers. Most commonly used equipment includes underwater lights, video cameras, nondestructive inspection equipment, communications, and remotely operated vehicles (ROVs).

Submersible battery-powered tools should be reviewed to ensure they meet diver safety criteria.

2.2.5.1 Ground Fault Detection System. A ground fault detection (GFD) and shutdown system is available to protect divers from electrical shock hazards. Shown in Figure 2-10, the GFD monitors the insulation resistance of the load circuit being used by the diver. When the ground fault resistance drops to a predetermined level, the GFD shuts off power to the load within 10 ms.

There are two versions of the GFD available: the standard and the Arctic version. Both have the same operating characteristics as shown below. The Arctic unit is newer and lighter and has components that can operate in a temperature range of -40 to +95°F while the standard unit operates in a range of +30 to +95°F.

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