By Letitia Stein

TAMPA, Fla. (Reuters) - The U.S. Coast Guard on Thursday said it had recovered a second body in the search for a family whose sailboat went missing off the Florida coast four days ago.

The body was found at 11:06 a.m. EDT (1506 GMT), four miles (6 km) from where the first body was recovered on Wednesday afternoon, the Coast Guard said in a news release. It did not disclose further details on the discovery.

Shortly after, an aircraft with U.S. Customs and Border Protection located a sailboat mast, approximately 101 miles (163 km) from Fort Myers, Florida, the release said.

Crews continued to search for survivors, the Coast Guard said in a Twitter post after the second body was discovered.

Ace Kimberly, 45, his two sons aged 13 and 15, and a 17-year-old daughter were last seen on Sunday when they set sail from Sarasota, Florida, headed to Fort Myers.

The vessel ran into a storm with 6-foot (1.8 m) seas on Sunday off Englewood, a community about 30 miles (48 km) south of Sarasota, according to authorities.

Earlier on Thursday, authorities located a bucket with a GPS navigator, birth certificates, a wallet and cell phone and other personal belongings.

Overnight, a response boat had witnessed a white flare in the area being searched. However, authorities cautioned that it could have been a reflection, or another type of false alarm.

"This is still an active search, although it is a dire situation," Captain Gregory Case, the St. Petersburg sector commander said at a news conference on Thursday morning.

The Coast Guard also did not immediately identify the body that was found on Wednesday afternoon, after they recovered water jugs, a pair of shoes, a basketball and other items from the family's 29-foot (9-meter) sailboat.

Green and yellow kayaks towed by the boat also have been recovered.

The Coast Guard has said the family had lived on the vessel for about a year. They were traveling to Fort Myers for repairs to the boat, which was in poor condition.

In addition to the Coast Guard, the search has involved several state and local maritime emergency responders.

(Reporting by Letitia Stein; Editing by Bill Trott and Alan Crosby)