SEPTEMBER 24, 2021 – Working underwater can be a dangerous, life-threatening job for divers who inspect and maintain facilities on the riverways. Divers adhere to strict guidelines and regulations to keep everyone safe.
“If an accident happens, it’s never an injury. It usually results in death,” said Jay Kochuga, the dive program coordinator for the U.S. Army Corps of Engineers Pittsburgh District.
Following strict guidelines helps keep divers alive, but divers still have a job to do. To help them accomplish their mission, the Pittsburgh District has a fleet of underwater remote operated vehicles (ROVs). The fleet supplements a team of 15 divers who perform inspections year-round at 39 facilities around the district, including locks and dams on the rivers, and flood-control reservoirs.
“Every time it’s a questionable scenario, we can send in a ROV instead of a diver,” Kochuga said.
The ROVs help the dive team perform jobs humans cannot do underwater, such as swim through strong river currents near a fixed-crest dam, enter confined spaces, or pilot areas with dangerous differential pressure. Differential pressure is formed whenever the water level in a lock chamber is either higher or lower than the river level. Differential pressure is most dangerous near a gate or valve, and it could suck in a diver and slam his body against a hard structure.
“This is where the ROV pays off. If something bad happens, and you have to cut the umbilical, you’re not writing a letter to a loved one to inform them someone was injured or possibly killed. No. You lose a piece of equipment,” Kochuga said.
The district’s newest ROV is the VideoRay PRO 5, which is equipped with a high-definition video and photo camera, a multibeam sonar, a claw that can rotate and grab objects, two powerful LED lights, and propelled thrusters that are twice as powerful as the previous version, allowing it to pilot through stronger currents. The PRO 5 is submergible down to 1,000 feet, with a multibeam sonar that can capture imagery up to 300 feet away.
The ROV’s manufacturing company, VideoRay, provided the Pittsburgh District with three days of operator and familiarization training for purchasing two new robotic systems.
Normally this unit costs $100,000, but the district paid $55,000 for each of the latest models available on the market. Kochuga’s team saved about half the cost by trading in two older units to the manufacturer for an upgrade.
That price tag may seem steep for something small enough to fit inside a suitcase, but Kochuga said the money is worth it.
“What’s the cost of keeping a diver safe? That’s limitless. You would never put a cost on human life, and the Pittsburgh District knows it,” he said.
These underwater robots not only prove the district’s commitment to putting people first, but they also highlight the importance of innovation to improve efficiency, Kochuga said. For example, any time the dive team needs to perform an inspection, the team requires five people. With the ROV, a single operator can lower the robot in the water and record video for a preliminary inspection, on his own.
“You could be anywhere in the district viewing whatever’s going on under the water. You’re able to identify a problem before initiating the entire dive team,” Kochuga said.
In the winter, the ROV saves divers from submerging in freezing waters longer than they need to. The vehicle can identify the exact location of a maintenance need, and the diver can jump in afterward to fix the problem. Divers are also limited by the Navy dive table on how long they can stay underwater, depending on depth, because of impact on their lungs. The ROV, on the other hand, can stay underwater for unlimited hours.
“Diving is a risky business, so anything you can do without putting a diver in the water, unless it’s absolutely necessary, helps mitigate that risk,” said Tom Glebas, a vice president at VideoRay.
The ROV has other capabilities. The mechanical claw can be used for various purposes, including running a winch line down to a vehicle or heavy object to pull it out of the water. The ROV records imagery to a computer with a large touch-screen display, packaged in a separate weatherproof hard case.
The robot is also easier to maintain than its predecessors. Inside, its mechanics are assembled with individual water-sealed modules. That means replacing a part is a plug-and-play process. Opening the ROV’s shell does not expose its electrical guts to the elements.
“It’s a big jump with easier servicing because you can just disconnect a module and replace it with a new one,” Glebas said.
Ultimately, the ROV will not replace a human diver. Even though the claw can open and close, it cannot turn a wrench or perform complicated maintenance tasks. What it offers instead is the ability to save time and save lives.
Story by Michel Sauret
U.S. Army Corps of Engineers Pittsburgh District