— People who live at the mouth of the Wando River are accustomed to occasional booms and crashes when shipping containers hit the ground of the nearby port terminal.

But when they heard a cacophony of splintering wood, crunching fiberglass and a roaring boat engine Friday night, residents of Wandolea and Hobcaw drives knew something wasn't right.

They turned on lights, spilled from their homes and rushed to the shoreline.

They saw a barely conscious man still at the wheel of a boat that had plowed through two docks, dislodged two other boats and got stuck under a third dock. His 250-horsepower Yamaha outboard was still at full throttle, constantly battering the third dock.

On Tuesday, investigators tried to explain the crash that critically injured 39-year-old Brooks Brown of North Shelmore Drive and likely did hundreds of thousands of dollars in damage to the docks and boats.

A preliminary probe indicated that Brown's boat might have struck a buoy just after 9 p.m. Friday, causing it to divert uncontrollably toward shore, said Lt. Robert McCullough of the S.C. Department of Natural Resources. Mount Pleasant police also found an open bottle of Corona beer in Brown's boat. They wrote in a report that he had been drinking.

Investigators hadn't yet talked with Brown, who underwent surgery during the weekend at Medical University Hospital. He is expected to recover.

If confirmed, such a buoy strike would be the second this spring in Charleston Harbor. A Charleston fire boat hit a buoy in April in a crash that authorities attributed to training lapses.

Lt. Tim McNamara, a spokesman for the Coast Guard's Sector Charleston, said basic safety precautions can prevent such accidents.

“People should pay attention to where they're going,” he said. “That's the bottom line.”

Brown's wife, Emily, said in a brief interview Tuesday that she, her husband and three daughters, including a 2-year-old, had spent some time on the water that evening, but the children became tired.

Brown dropped off his family at Shem Creek, then traveled under the Arthur Ravenel Jr. Bridge. He planned to steer down the Wando River and dock his boat on the connecting Hobcaw Creek in the I'On subdivision, where he lives. He wanted it handy for the Memorial Day weekend.

“He was just bringing the boat around,” his wife said.

A red buoy sits in the Wando River about 500 yards from the first damaged dock, in front of Carol Webster's vacation home.

Webster, 49, a New Jersey resident, was watching television with her family when she heard the crash. The boat had ripped off the face of Webster's dock and continued barreling forward.

Boats often round the nearby point occupied by Hobcaw Yacht Club, then head down the creek, Webster said. She tried to fathom a boat hitting something in the open river or simply making that turn too soon.

It also was dark, she said. But a full moon was low in the sky.

“At some point, his throttle must have been jammed forward,” Webster said. “That's the only thing that makes sense.”

The craft then destroyed the floating portion of a neighbor's dock, toppled some of its supporting pylons and sent a connected metal plank plunging into the water. The neighbor's boat fell from its lift and capsized. Authorities found it floating toward the Ravenel Bridge.

Brown's boat caromed northward into Tiffin Lamoreaux's dock off Hobcaw Drive.

The 30-year-old was checking on her two sleeping sons when she heard the racket. She looked out and saw that her 26-foot Sea Ray was gone. It had splashed into the river and floated upright about five docks to the south.

It was replaced by a stranger's boat that was still running. The man muttered that his family members had been thrown overboard.

“It was horrifying,” Lamoreaux said. “I went from thinking our boat was stolen to thinking children were missing in the water.”

Lamoreaux reckoned that the crash did $100,000 in damage to her boat and dock. An estimate for all the damage had not been done.

Brown's confused statement that his family was missing ignited a search that included state wildlife agents, deputies, police officers from North Charleston and Coast Guardsmen.

A Wandolea Drive resident who called 911 added to the urgency. The caller saw two boats floating nearby, including one that had flipped.

“We're assuming that there is somebody in there,” she told a dispatcher. “It's dark. We can't see.”

Exactly what happened is something that McCullough, the DNR lieutenant, said investigators might determine once they interview the boater.

Brown's wife said Tuesday that he had been speaking with loved ones. “He's doing OK,” she said. “He's much better. That's what matters.”

Reach Andrew Knapp at 937-5414 or twitter.com/offlede.