SUDDEN VALLEY - Another effort to recover the body of a swimmer missing in Lake Whatcom turned up empty Wednesday, July 11, despite help from an underwater camera and sonar.

David Arthur Johnston, 40, went under the water about 1 p.m. Sunday in the south end of the lake while swimming near a small pleasure boat, according to the Whatcom County Sheriff's Office.

A team of 40 searchers could not find him. Visibility under the water was about 5 feet to 15 feet, hampering divers. In that part of the lake, south of Reveille Island, the water is about 300 feet deep. Johnston was presumed drowned, and the search was suspended at noon Monday.

Craig Thorngren of Arlington then volunteered use of his "remote operated underwater vehicle" or ROV - a submersible digital camera with sonar and a small grabbing arm. Thorngren, a 21-year veteran of the U.S. Coast Guard, has filmed shark shows for the History Channel and the National Geographic Channel. He owns Submerged Recovery & Inspection Services and donated his time and equipment Wednesday.

"When you need to help someone in their time of need, you help them," he said.

The ROV is about the size of a gym bag, or a pair of "those 32-packs of pop," said Whatcom County Sheriff's Deputy George Ratayczak. The recovery team used it to sweep the bottom of the lake.

They focused on three spots, mostly about 200 yards off the shore: the point where GPS suggested the first 911 call was made from the boat, the point where Johnston's friends remembered they last saw him, and the point their boat had drifted to by the time deputies picked them up.

The bottom of the lake was full of massive fallen trees, old beer bottles and other scattered debris. It was also "unbelievably dark," Thorngren said, so the team was relying on sonar. With the camera they could see about two or three feet ahead of the ROV; with the sonar, they could see 121 feet in a range of about 130 degrees.

But on Wednesday - what was expected to be the last recovery effort by the Sheriff's Office, unless new information comes up - they didn't find Johnston's body.

"If the gentleman was in that area, we would have seen him," Thorngren said. "This is the first time in a long time I've not come back with (what we were looking for) right off the bat."

Johnston was a Gulf War veteran and an auto mechanic. Friends remembered him as an avid fisherman, boater and hockey fan.

Reach CALEB HUTTON at caleb.hutton@bellinghamherald.com or call 715-2276.