The U.S. Coast Guard said it was searching for 39 people after the boat that was carrying them from the Bahamas capsized off the Atlantic coast of Florida on Saturday night.

Rescuers learned of the accident on Tuesday morning, when a boater, who was described as a “good Samaritan,” found a man clinging to the capsized vessel, the Coast Guard said.

The man said he had been hanging on to the boat since Saturday night, when it left Bimini, the Bahamas, and began heading north before running into severe weather.

A photo posted by the Coast Guard on Twitter showed the man straddling the boat’s hull.

The boat capsized about 45 miles east of the Fort Pierce Inlet, the Coast Guard said. It was not immediately clear on Tuesday what type of boat it was. No one aboard was wearing a life jacket, the Coast Guard said.

“This is a suspected human smuggling venture,” the Coast Guard said on Twitter.

Cutters and helicopters have been searching the area for signs of survivors, the Coast Guard said. The Fort Pierce Inlet is about 156 miles northwest of Bimini.

The search effort on Tuesday came after at least 31 people were rescued from the water on Friday when their boat capsized five miles west of Bimini, according to the Coast Guard and the Royal Bahamas Defense Force.

The Coast Guard said on Twitter that vessels regularly patrol the waters around Haiti, Puerto Rico and the Bahamas “to ensure safety at sea.” The agency warned people not to board unsafe boats.

“Navigating the seas in overloaded and less than seaworthy vessels is extremely dangerous and can result in loss of life,” the Coast Guard said.

Vimal Patel contributed reporting.