Water Patrol unveils sonar scanner, submarine to assist in lake searches

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As Minnesotans prepare for boating and swimming season, the Hennepin County Water Patrol is testing out a new sonar scanner and a remote-controlled submarine.

On a lake like Lake Minnetonka, finding small objects underwater is a big problem, which is why deputies are using the new side-scanning sonar device to see what their eyes cannot.

It swims just 15 feet off the lake’s bottom, sending reflective images back to a set of computers on the boat.

Deputy Troy Kostohryz says it’s like a fish locator on steroids.

“It gives a clearer picture and it gives us a better ping off the bottom and that gives us a clearer picture of what we are looking for,” he said.

At their best, search and rescue missions are always challenging. Especially when the lake is large, the water is turbid and there is lots of weeds at the bottom. That’s why this new technology gives those crews an extra set of eyes in the water.

One of those new sets of eyes comes in the form of the submarine.

“We’ll use that sonar to swim up to the object,” Kostohryz said. “Once we get the object in view, we’ll use the camera and either hook onto it with the hand up front.”

Deputies maneuvered the sub into a boat wreck near Big Island to show how it can find and recover objects from the lake bottom.

“We’ve found airplanes, boats,” Kostohryz added. “We’ve found boats so that people can retrieve them from a fire. We take the ROV down there, we can mark it for the people so they can get a retrieval unit in come get it.”

Most importantly, the sub can help them find drowning victims, too.

“Unfortunately people do go into the water and we can use that equipment to look for the deceased or find navigational hazards that may be under the water to removed them so no one else runs into them or gets hurt,” Kostohryz said.

The new remote-controlled submarine can even search under the ice during the winter giving the Sheriff’s Department better and faster recoveries.