Stonington ― State investigators have concluded that a Stonington man was legally drunk - more than twice the legal limit - when he crashed his boat into a breakwater in Stonington Harbor, killing himself and his friend last summer.

The crash that killed the driver, 54-year-old David Motherway Jr. of Stonington, and his passenger, Brian Collie, 52, of Littleton, Colo., was ruled accidental and “the result of alcohol use, drug use, improper lookout and operator inattention,” according to the report released Monday by the state Department of Energy and Environmental Protection.

Motherway and Collie died of blunt trauma injuries and were still in the boat when it was discovered floating by a fisherman at 7:17 a.m. on Aug. 20, 2022 in the area of White Rock, which is located southwest of Lord’s Point.

The discovery prompted a search for survivors by police, firefighters, DEEP and a Coast Guard boat and helicopter.

DEEP’s Division of State Environmental Conservation Police, which led the investigation into the cause of the fatal crash, determined that Motherway’s 22-foot center console boat was traveling 35 miles per hour when it struck the west side of the inner Stonington breakwater at 12:30 a.m. Several people in Stonington reported to police hearing a loud bang coming from the water about that time.

While there is no navigable channel to the west of the breakwater, investigators said it is sometimes used by smaller vessels exiting and entering Stonington Harbor. The GPS on Motherway’s boat “showed that the operator habitually used the body of water to the west of the inner/west breakwater,” the report states.

The crash, captured on video from a home on Wamphassuc Point, occurred at 12:30 a.m., about a half hour after Motherway’s boat left the West Harbor on Fisher’s Island , N.Y. A witness interviewed by police said Motherway was at the Pequot Inn on Fishers Island, N.Y. from about 11 p.m. to midnight.

Motherway had a blood alcohol concentration of .179, or more than twice the legal limit of .08 to be driving a motor vehicle or operating a boat, according to results of test performed by the Office of the Chief Medical Examiner. The toxicology report also determined there was “levels of THC” in Motherway’s system. Tetrahydrocannabinol, or THC, is the active ingredient in cannabis.

Police said they “discovered a total of 8 opened and empty 16-ounce cans of beer on the vessel,” after the crash.

Motherway and Collie had been fishing that evening, photos and videos from Collie’s cell phone revealed. The two men had earlier visited On the Waterfront Restaurant in New London. Surveillance footage from the restaurant shows the two men entering at 8:15 p.m. on Aug. 19 ordering an alcoholic beverage, dinner and sharing a bottle of wine. They left the restaurant at 9:19 p.m.

Motherway, married with three children, was a member of the Stonington Board of Finance and a graduate of the U.S. Coast Guard Academy.