At 76, disabled, with half the roof of her Grand Bahama home blown off and facing the prospect of months without electricity, Myrtle Cartwright decided she had to leave.

Ms. Cartwright escaped in luxury: On Friday, she boarded Bahamas Paradise Cruise Line’s Grand Celebration with about 1,200 other Hurricane Dorian survivors and headed for Palm Beach, Fla. She had her own handicap-accessible cabin.

“They even had a medical attendant come and see if I was O.K., because I have hypertension,” Ms. Cartwright said. “Someone had a heart attack on the ship and a helicopter took them off the ship at 12 o’clock at night to the hospital. If they were at Freeport, they would not have made it.”

The Grand Celebration was the first to dock at the Grand Bahama port last week, and the ship arrived packed with doctors and nurses. Bahamas Paradise only sails to the Bahamas, and so company officials decided that instead of sidelining its ships and waiting for better times, it would launch a humanitarian mission to help the thousands of people forced from their homes who lacked food and running water.