Authorities have detailed the dramatic but unsuccessful lifesaving effort by members of a scuba diving group off the North Shore to save one of their own who ended up unconscious at the bottom of Lake Superior.

Aaron Timmerman, 42, of New Hope, was identified by the Lake County Sheriff’s Office as the diver who died Saturday afternoon while exploring the popular Madeira shipwreck near the Split Rock Lighthouse.

People nearby saw Timmerman “surface and call for help” before he went under before anyone could get to him, the Sheriff’s Office said in a statement.

Two fellow divers got to Timmerman on the lake bottom and raised him to the surface, the statement continued. Once he was brought to shore, other divers began trying to revive him.

Authorities have yet to disclose a cause of death. Timmerman, who worked in information technology, leaves behind a wife and two children.

Timmerman “left the world the way he lived in it, fervently pursuing one of his life’s many passions, scuba diving in Lake Superior,” reads his online obituary. “The twinkle in his eye let the world know he was up for whatever fun or mischief lay ahead.”

North Shore Cruises Owner Jay Hanson was in the area at the time, and he told WDIO-TV in Duluth that one of the divers said Timmerman was taking an instructional class at the time.

The sinking of the cargo ship Madeira during a storm in 1905 helped bring about the lighthouse. One of the crew climbed the cliffs with a rope and saved most of his shipmates.

The wreckage, which attracts divers by the hundreds every year, sits just off shore in relatively shallow water. On clear days, the remnants can be seen from the overhanging bluffs.