As search teams spotted a body and more personal items believed to belong to a family who vanished on a sailboat off Florida's Gulf Coast, hopes of a safe rescue on Thursday were quickly fading.

The person who was found was not immediately identified, but searchers were now looking for three members of the missing Kimberly family, not four, Coast Guard Capt. Gregory Case said. Coast Guard officials were set to give updates at a news conference later Thursday moing.

The person whose body was recovered was wearing a life vest, Case said. Other items found in the search area included a flare, two kayaks and additional life jackets.

Ace Kimberly, his daughter Rebecca, 17, and sons Doy, 15, and Roger, 13, haven't been heard from since Sunday afteoon, when Ace phoned his brother to report the family had been caught up in six-foot waves and were "attempting to survive."

The family was sailing to Fort Myers from Sarasota to have repairs done on the sailboat. Ace's brother contacted the Coast Guard Tuesday after the family failed to reach their destination.

The kayaks -- one green and one yellow -- were found near the quartet's last-known position. A seperate debris field about 33 miles off the coast of South Florida contained a tarp, four water bottles that had been tied together, a pair of teis shoes, a basketball, a propane tank and six life jackets.

"We're searching in a particular spot," Case said Wednesday afteoon. "We kind of have tracked their voyage and where they should be, and we've backdrifted that."

The U.S. Coast Guard launched a HC-130 Hercules airplane from Clearwater, and several other vessels from Stations Cortez and Fort Myers, Petty Officer 2nd Class Ashley J. Johnson told the News-Press. The Maritime Emergency Response Team had also been activated.

The 29-foot boat did not have a name or a radio, CBS reported. Case said officials never received a distress call.

He said the Kimberly family was "feeling very anxious and upset, and they're hoping for the best."

Mariners with any information were asked to contact the Coast Guard’s St. Petersburg sector at 727-824-7506.

The Associated Press contributed to this report.

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