Page 605 - The ROV Manual - A User Guide for Remotely Operated Vehicles 2nd edition

22.1 Standard operating procedures 605
area before the ROV is recovered. No vehicle recovery should be started unless prior approval
is gained from the diving supervisor.
• Clear, open, and direct lines of communication should be maintained between the ROV operator
and the diving supervisor. Emergency procedures should be fully briefed and understood before the beginning of the concurrent operation.
22.1.3.4 Precautions and limitations
The following precautions should be exercised to properly protect the ROV equipment while oper- ating within its design limitations (Wernli, 1998):
• The ROV should only be operated by approved and appropriately trained company operators.
• Piloting ROVs in excess of 8 hours within any 12-hour period subjects the operator to excessive
fatigue, thus possibly compromising personnel and equipment safety. If extended periods in the
water are planned, a relief pilot should be scheduled or shifts should be staggered.
• The launch and recovery phase of the dive cycle is probably the most dangerous portion of the dive. The vehicle and launch platform are subjected to an inordinate amount of risk to damage
while the vehicle is suspended in air (lift from the deck until contact with the water). Weather conditions at the time of launch should not exceed company-specified limitations. This would increase the risk of damage to the equipment to an unacceptable level.
• The ROV, as well as system components, should not be operated outside of the manufacturer- specified operating parameters.
• When operating from dynamically positioned vessels or vessels under station-keeping (as specified above), ensure that the vehicle is kept clear of thrusters and surface obstructions.
• ROV operations should not be conducted in low water visibility (less than 4 ft/1.2 m) or in uncharted and/or unstructured areas unless the vehicle is equipped with submersible-mounted imaging sonar.
• Approval from command and possibly the insurance company may be required when operating the ROV in hazardous circumstances. Examples of such circumstances include:
1. HAZMAT spills
2. Use of explosives
3. Working within underwater structures
4. Extreme dynamic environments caused by waves and/or surge
• Ensure demobilization procedures are properly followed to include postoperation maintenance
and storage procedures.
22.1.3.5 Night operations and extreme operational environments
22.1.3.5.1 Night operations
As discussed in previous chapters, light is subject to scattering and absorption in water. The largest negative factor in working at night is the enhanced effect of backscattering due to the lack of ambi- ent lighting (causing the auto iris on most CCD cameras to open further, amplifying the backscatter effect). The only significant source of lighting at night to illuminate the item of interest is the sub- mersible’s lights; therefore, the submersible may have a lower effective range of vision during night operations. The submersible should be moved closer to the item of interest while the lights are set on a slightly lower setting to counter the enhanced backscattering.