Fernandes persuaded the girl to follow him while she was waiting for a friend outside the restaurant one evening. Prosecuting lawyer James Kellam said he led her around the ship to a toilet cubicle, locked the door and sexually assaulted her.
Kellam said the girl described her ordeal as "feeling horrible" and talking about it as "acutely embarrassing". The girl eventually confided in a friend she met on the cruise ship who persuaded her to talk to a youth worker.
Fernandes was arrested when the liner docked in Southampton, according to a report in the Daily Echo, a leading daily published from Hampshire.
Megan Toplis, lawyer for Fernandes, said he was a man of good character who had pleaded guilty at the earliest opportunity. Fernandes had worked on cruise ships for nine years and there had "never been a problem or question as to his integrity", she said.
Toplis said Fernandes had not used force, nor used coercion or made threats to the girl. He had "lost sight of rights and wrongs", she said and added that he had shown genuine remorse and was extremely sorry for what he had done.
She said he had received no visitors while in custody and had been too ashamed to let his family know what he had done. Fernandes sobbed and clutched a crucifix close to his chest as the judge sentenced him to 15 months. He declined to make a recommendation for deportation to India.