Highly sophisticated crawlers can install heavy equipment and carry out test drillings the ocean floor thousands of meters below the ocean surface. This subsea crawler manipulator is designed to work on the ocean floor at depths to 4,000 meters. All major functions are powered by hydraulics, including its crawler drive, manipulator arm with several linear and rotational drives, and powerful gripper. It contains 23 hydraulic manifolds, 27 cylinders, and seven hydraulic motors, all supplied by Bosch Rexroth.
All components for this equipment must tolerate high ambient pressures. Every 10 m water depth increases ambient hydrostatic pressure by 1 bar. This means equipment that will used at 5,000-m depths must accommodate ambient pressure of 500 bar. A pressure compensator is the key to success for machines worikng at these depths. Obviously, equipment must also function in salt water, so components must exhibit high corrosion resistance. This requires components to be made either of stainless steel or other corrosion-resistant materials, have special coatings, or both. To avoid electrical shorts, all solenoid-operated hydraulic valves must be enclosed and secured against water ingress.
Finally, designers have to consider that these machines cannot easily be hoisted up to the surface for repair. This makes long, maintenance-free life a high priority.
