An American couple who had departed from Virginia and were spending the winter cruising in the Caribbean went missing this month while sailing off Grenada, and their boat turned up empty in neighboring St. Vincent and the Grenadines.

Their disappearance came around the same time three men escaped from a prison in Grenada and made their getaway by boat to St. Vincent and the Grenadines, the authorities in those islands said.

In a statement, the Royal Grenada Police Force did not identify the two Americans but said that it was looking into possible harm to them in connection to the prisoners’ escape.

According to the Salty Dawg Sailing Association, a nonprofit that brings together sailing and cruising enthusiasts, a skipper notified it on Feb. 21 that a member’s yacht called Simplicity was found anchored and abandoned off a beach on the southern coast of St. Vincent.

The skipper boarded the catamaran and noted that its owners were not onboard, the association’s statement said. The skipper contacted the Saint Vincent and the Grenadines Coast Guard, which then notified the local police.

The missing boat owners were identified as Ralph Hendry, 66, and Kathy Brandel, 71, by the association and Ms. Brandel’s son, Nick Buro, who said the couple, originally from Virginia, were married for 27 years.

Mr. Hendry and Ms. Brandel were experienced sailors who lived in their boat. They recently completed their sailing club’s “Caribbean Rally” — cruising from Hampton, Va., to the island of Antigua to end 2023 with a celebration — and they were spending the remainder of the winter cruising the Caribbean, according to a statement from the club.

The association said that it had a tracking map to follow members’ boats and that it showed the couple had anchored in Grenada before docking off St. Vincent. The St. Vincent and the Grenadines Coast Guard secured the boat and the St. Royal St. Vincent and the Grenadines Police Force were investigating with the U.S. Embassy and the Royal Grenada Police Force, according to the statement from the association.

Separately, the Royal Grenada Police Force said in a Feb. 22 statement that three men who escaped from a prison in Grenada on Feb. 18 made their way to St. Vincent using a yacht that had been docked in the St. George area of Grenada. The force said that the two boat occupants, whom it did not name, were American citizens.

The prisoners were recaptured on Feb. 21, the same day that the couple’s vessel was found.

The Grenada authorities identified the prisoners as Trevon Robertson, 19; Abita Stanislaus, 25; and Ron Mitchell, 30.

They had been previously charged, jointly, in a violent robbery case in December. Mr. Mitchell also faced various separate charges that included causing harm, indecent assault and rape, the Grenada police said.

In a joint family statement on Saturday, Mr. Buro and Bryan Hendry, Mr. Hendry’s son, thanked the cruising community for its support and help in the search but asked them to stand down.

“We also want to applaud the St. Vincent authorities for their quick actions in securing Simplicity and their brave, swift response that led to the apprehension of three dangerous fugitives,” according to the family statement. It added: “We greatly appreciate the coordination of the St. Vincent and Royal Grenadian Police forces and Coast Guards in investigating these events.”

The Royal Grenada Police Force did not respond to an inquiry on Sunday. The department said in the release that the investigation was “in its infancy stage” and that a team of investigators and a forensic specialist had been dispatched to St. Vincent.

Bob Osborn, president of the sailing club, described the couple as warmhearted and capable and their disappearance “a very upsetting event.”

He added, “Our hopes and prayers are with Ralph and Kathy and the family who love them.”

A GoFundMe page started by a family friend seeking to help with costs related to their disappearance described Mr. Hendry and Ms. Brandel as “experienced adventurers” and said they had “spent their retirement sailing aboard Simplicity, spending summers in New England and embracing the warmth of Caribbean winters.”