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Richard Glenn of Glenn Underwater Services has been providing underwater services to the hydroelectric industry here in the US and internationally for over 30 years. They have provided services in the United States, South America, the Caribbean, Middle East, West Africa, and Europe. Glenn Underwater has utilized larger Remotely Operated Vehicle (ROV’s) in the inshore market for over 22 years for underwater inspections where extensive penetrations and depths are problematic. Since taking delivery of the SeaBotix LBV200L2 MiniROV in October of 2007, Glenn Underwater has performed complete detailed inspection services on over 22 hydroelectric facilities. With four powerful thrusters and a long umbilical (250 meters/820 ft), the LBV200L2 is uniquely suited for the inspection of civil structures requiring long penetrations, entry into confined spaces, limited visibility, and/or the need to inspect and map defects on large surface areas. Glenn Underwater has an assortment of instrumentation that can be employed with the LBV200L: Ultrasonic thickness, sonar, and acoustical positioning, as well as the ability to grasp and manipulate objects as heavy as 45kg (100lb). President Richard Glenn said, “The SeaBotix LBV200L2 finally brings the technology typically only seen in larger offshore vehicles to a small, light-weight, and manageable system with auto heading, auto depth, sonar, etc. Many of our sites are remote and difficult to transport equipment. On many older hydroelectric dams, the roads are difficult to transverse, and in some cases, the equipment has to be hand carried long distances to access the entry point. The angle of the camera travel is extremely important when viewing the crown and invert of intakes and discharge tunnels. The vehicle’s ability to turn on its axis in a confined area is very helpful. The system is very well packaged, easy to ship and very modular, which is important on remote sites. Change out of accessories is quick.” The hydroelectric facilities that Glenn Underwater has inspected with the SeaBotix LBV200L range in age from 1918 to 1954, and the depth of water ranges between 60 feet to 190 feet. Most of the dams in the United States are within this range, and most do not have accurate drawings of the substructure. They are typically large mass, concrete dams that include intake tunnels, intake structures, penstocks, head gates, trash racks, etc. The inspections have included the entire upstream face of each dam, trash racks, intake gates, guides, concrete surfaces, powerhouse toes, and penstocks. For many of the hydro plants, utilizing the SeaBotix LBV reduced the shut down of the number of generating units. Glenn Underwater only had to tag out units while inspecting on the upstream side, which prevented extensive work to apply physical brakes and locks to the turbine generators and head gates. Most of Glenn’s projects required the ROV to do the initial survey (at some locations they did not even attempt to put a diver into a structure that the ROV was inspecting). Several of the utilities and engineering firms required that they use both the ROV and divers. Once the survey was performed, the diver then entered to perform more detailed data collecting. Divers were used to clean surfaces where bio fouling was heavy, to employ special instrumentation, and to take measurements of suspect areas for detailed CAD drawings. The SeaBotix LBV200L2 MiniROV and diver worked well together, greatly reducing the exposure of the diver. Eliminating one or the other would not have been beneficial to the owner of the dam -- both were needed on many of the inspections.
The LBV reduced the time for deep inspections by at least 40% and by 70% for tunnels and other penetrations. Mobilization and plant shut down are much easier with the ROV. At most locations, Glenn Underwater was able to have a team onsite in a day. With a dive crew, it took two to five days to mobilize the crew before getting onsite. Prior to using the LBV200L2, a minimum crew for diving inspections was four, and up to seven divers and tenders were used for deeper or penetration dives. With the LBV200L2, a typical crew incorporates the pilot and tender. If data collection is expected to be heavy, then an engineer is onsite also. President Glenn concluded, “Your cost savings really begins past 60 to 70-feet, especially at depths greater than 100 feet where a decompression chamber and depth pay are required for the divers. Your biggest savings involves SAFETY, SAFETY, and SAFETY ...let the ROV identify the hazards during its investigation and not the diver.” For more information on Glenn Underwater Services, contact Richard Glenn at www.glenndiving.com. |
Performing hydroelectric inspections on budget while reducing hazards for divers and their support team is key to the long-term success of any underwater service company. Glenn Underwater Services, Inc. is saving time expenses, reducing hazards, and greatly expanding their capabilities by utilizing the SeaBotix LBV200L2 Mini Remotely Operated Vehicle (ROV) to inspect hydroelectric dams. 
President Glenn said, “We relied heavily on the SeaBotix LBV to reduce man hours in the water -- less exposure reduces risk in deep water, tunnel/ penstock penetrations, and areas of possible differential pressures. This is very important. We now employ the LBV200L2 before any diver enters the water on the upstream side of a dam where differential pressures may be present. It is not always possible to detect leakage from the surface. It can be a lifesaver.”