The U.S. Coast Guard rescued a man from the water near the Richmond-San Rafael Bridge after he fell off his boat, Coast Guard Petty Officer Laura Alcon said.
Alcon says the boat, which was going about 8 knots, traveled more than three miles on the other side of the bay before crashing near Pier 70.
The Coast Guard received a call at 11:26 a.m. Wednesday reporting a person in the water. They were able to quickly rescue the man because a patrol boat was in the area on patrol.
But the rescuers had no idea where the 32-foot powerboat, which looks like a trawler or tugboat had gone.
About 20 minutes later, the Coast Guard received a call from a good Samaritan at Pier 70 in San Francisco who reported that a boat had just crashed into a dry dock. That man said although the boat was about a football field away from him, he heard a loud "boom" when it hit the dock.
The Coast Guard said there was no damage to the dock and minimal damage to the vessel.
Nobody was hurt when the boat crashed into the dock either.
Officers were still investigating how the man fell overboard.
Bay City News contributed to this report.