Cowardice at sea is no crime -- at least in the U.S.

Captain Francesco Schettino is seen in this undated file photo released on January 18, 2012.

NEW YORK (Reuters) - When Captain Francesco Schettino hopped a life boat after the Costa Concordia hit a rock off the Tuscany coast, he violated a sacred maritime tradition: that a captain should be the last to leave his ship.

He also is accused of violating the law. Italian maritime code criminalizes the act of abandoning ship and Schettino was placed under house arrest, accused of causing the disaster and then jumping ship before the evacuation was complete.

Countries have adopted different maritime codes over the centuries and the responsibilities of a captain can be traced to a 12th century French document called the Rolls of Oleron, which established the first known outlines of maritime law.

The sailor's code that's developed from the rolls - or rules - has been celebrated in everything from Conrad's Lord Jim, about a young seaman who abandons a ship in distress, to the 1960s U.S. television show Gilligan's Island theme song, with the lyric, "If not for the courage of the fearless crew, The Minnow would be lost!"

In the United States, the rule that a captain should be the last to leave a distressed ship is not a criminal offense. The Westlaw online legal research service shows the phrase "abandon ship" turned up 618 decisions but none addressed a captain's decision to leave a ship before his passengers.

The closest U.S. law that appears to take on the act of leaving a ship before passengers and crew is seaman's manslaughter, which criminalizes a captain's misconduct or negligence that result in deaths. A version of the statute was used to convict a seaman in the 19th century who abandoned 31 passengers aboard a sinking ship on its way to Philadelphia from Liverpool.

But the seaman' manslaughter has rarely been invoked in recent years -- cited in just 22 court decisions since 1976, none of which involved accusations against a captain leaving a ship prematurely, according to Westlaw.

The issue of abandoning ship has been discussed widely since the Costa Concordia's crash last week. According to the Italian Coast Guard, Schettino not only jumped into a lifeboat before there had been an accounting of the more than 4,000 passengers and crew, he also refused a coast guard's plea to return.

Schettino, who was arrested a day after the boat capsized, has denied accusations that he acted cowardly. He says he fell into the lifeboat while helping other passengers, according to a report in the Italian newspaper La Repubblica.

THE SAILOR'S HONOR CODE

In Italy, a commander who leaves before his passengers can be sent to jail for up to two years. If he jumps ship and people die, he can be sentenced to eight years in jail.

"It's based on the sailor's honor code," said Luca C.M. Melchionna, a professor at St. John's University School of Law in New York.

The concept that a ship's master has specific duties was popularized in Britain by Eleanor of Acquitaine around 1160, after she had become the Queen of England. Based on the Rolls of Oleron, the rules mostly addressed commercial concerns like the condition of cargo.

Over time, different countries adopted aspects of the Rolls for their admiralty law. After the sinking of Titanic in 1912, several nations signed the International Convention for the Safety of Life at Sea, which addressed safety requirements for ships such as the number of lifeboats needed. The treaty requires that the master of a ship at sea "proceed with all speed" to help any person in distress, if possible. It doesn't mention when it's acceptable for a captain to leave a ship in danger.

"There is no basis in international law for the notion that the captain goes down with the ship, or that he is the last to leave the ship," said Vice Admiral Sir Alan Massey, chief executive of the UK Maritime and Coastguard Agency and a former senior officer in the Royal Navy.

It has been up to individual countries to enact their own criminal maritime laws. In the U.S., for example, the seaman's manslaughter statute was passed in the mid-19th century after several fatal steamboat accidents.

There's no shortage of inspiring tales of seamen following the honor code. William Lewis Herndon, commander of the commercial mail steamer Central America in the 19th century, got women and children safely off the sinking ship, and stayed behind and drowned with more than 400 passengers and crew who couldn't escape. Though historical accounts differ on the death of Edward John Smith, the captain of the Titanic, in the 1997 movie he's shown stoically gripping the ship's wheel before water gushes into the bridge and kills him.

Of course, not every seafaring figure with a story was a hero. A yarn that has haunted mariners for years comes from Conrad's Lord Jim, who fantasized about being a hero if an emergency ever arose at sea, said Craig Allen, Sr., a visiting professor of maritime studies at the U.S. Coast Guard Academy.

"When the emergency really did arise he proved to be a coward instead," he said.

(Additional reporting by Estelle Shirbon in London and Silvia Aloisi in Rome; Editing by Doina Chiacu)