Rov 101

ROV 101

The old saying goes that a chain is only as strong as its weakest link. Accordingly, all components of an ROV system should be rated to the maximum operating depth of the underwater environment anticipated.

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Figure 3.1 ROV submersible components.

The deeper the operating depth, the larger the component wall thicknesses should be for the air-filled spaces (pressure-resistant housings) on the vehicle. This increased wall thickness results in an increased vehicle weight, which requires a larger floatation system to counter the additional weight. This causes an increase in drag, which requires more power. More power demands a larger cable, which further increases drag, and so on…

Careful consideration should be given during the design phase of any ROV system to avoid over-engineering the vehicle. By saving weight and cost during the design process, the user will receive an ROV that has the capability of providing a cost-effective operation. However, one must be cautious as 'bells and whistles' are often added during the process.

Components of an ROV system

Frame

The frame of the ROV provides a firm platform for mounting, or attaching, the necessary mechanical, electrical, and propulsion components. This includes items such as sonar, cameras, lighting, manipulator, scientific sensor, and sampling equipment. ROV frames have been made of materials ranging from plastic composites to aluminum tubing. In general, the materials used are chosen to give the maximum strength with the minimum weight. Since weight has to be offset with buoyancy, this is critical.

The ROV frame must also comply with regulations concerning load and lift path strength. The frame can range in size from 6 in. × 6 in. to 20 ft × 20 ft. The size of the frame is dependent upon the following criteria:

• Weight of the complete ROV unit in air

• Volume of the onboard equipment

• Volume of the sensors and tooling

• Volume of the buoyancy

• Load-bearing criteria...