Gregoire, 56, was kayaking with a friend when his kayak flipped over. The incident was reported around 2:40 p.m. by a professional mariner who was mooring a motorboat in the area, according to the Coast Guard.
Gregoire apparently got too close to a tugboat that was repositioning a barge and got caught in the boat’s wash, San Francisco police spokesman Officer Carlos Manfredi said.
According to the Biz Times, Gregoire was known as an “eccentric,” with one former colleague describing him as “larger than life.”
Earlier in life, Gregoire had, the Biz Times reports, had nautical jobs, as both a merchant marine and as a lobsterman.
More recently, Gregoire had worked in commercial real estate “and then the bottom fell out of the market and he sort of fell out of the business,” the colleague told the Biz Times.
Most recently, he had been working as a tour guide, they report, for a cable car trolley company.
A joint search was conducted Sunday afternoon by the San Francisco Fire and Police departments and the Coast Guard, involving a helicopter, boats and divers. According to SFFD Assistant Chief Dave Franklin, they searched “all of the likely locations where the man could be.”
The Coast Guard and police continued to search the Bay for about 18 hours for Gregoire before calling off the search shortly before 9:30 a.m. Monday.
Authorities said that because of the time that has lapsed since he went into the water, it is unlikely that Gregoire is still alive.