Darrell Bryan, president and Chief executive officer of Clipper Vacations, was in his office and saw the boat leaving.
When a tugboat went to retrieve the boat they discovered there was a man on board and Seattle Police were called.
The man told police he had planned to take the boat to West Seattle.
According to an officer that was part of the response, the man was operating the Clipper when alarms on board went off and he didn't know what to do.
Officers say he appeared homeless and had signs of mental issues.
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