By Yeganeh Torbati

ABOARD THE CHARLES DE GAULLE, Dec 19 (Reuters) - French and U.S. officials boast of the closeness of their military alliance, as highlighted by Saturday's visit from U.S. Defense Secretary Ash Carter to a French aircraft carrier in the Gulf.

But even at sea, some cultural differences are apparent: French sailors can imbibe alcohol within moderation while on ship, while American sailors follow a policy of almost total abstinence.

There are no fewer than four bars on the Charles de Gaulle, where troops can purchase one alcoholic drink per day.

On Saturday morning, French sailors prepared and served coffee behind a large curved bar outfitted with wooden stools. A wall sign advertised available drinks, including Heineken or draft beers for 1.25 euros ($1.36), or Baileys, Johnnie Walker or wine for 1.50 euros ($1.63).

"We are French," said a spokesman for the French Navy, Commander Lionel Delort. "Wine is very appreciated on board."

Not so within the U.S. Navy, which has a strict no-drinking policy aboard its ships, with few exceptions. For instance, if a vessel has been at sea for 45 consecutive days or more, sailors are allowed to have two beers, on a one-time basis.

Carter's visit on Saturday to the Charles de Gaulle aircraft carrier was designed to highlight the joint resolve of U.S. and French forces to defeat Islamic State, which claimed responsibility for attacks that killed 130 people in Paris last month. Both countries are conducting air strikes against the militants in Syria and Iraq.

There are about 10 U.S. service personnel at any one time on the Charles de Gaulle, where they are governed by French rules of conduct - meaning they can drink, too.

"It's a cultural thing. We view alcohol very differently than the French do," said Anthony, a U.S. Navy lieutenant, explaining the U.S. policy. He declined to give his last name.

The Royal Canadian Navy last year banned alcohol at sea except for special occasions, after allegations of drunken misconduct by some crew while at port in San Diego.

To prevent the risk of tipsy sailors around deadly weaponry, the French use an electronic scanning system to track who has already reached the limit of a drink per day.

The Charles de Gaulle began its long-planned current deployment on Nov. 18, days after the Paris assaults. During 10 days in the eastern Mediterranean, it launched 10 to 15 flight missions per day targeting Islamic State, and is due to resume operations soon, after arriving in the Gulf on Friday.

During a recent lunch, sailors asked for a second bottle of wine but were refused by their quartermaster, Delort recounted.

"This is not a spring break," he said. "You have to be fit." ($1 = 0.9206 euros) (Yeganeh.Torbati@thomsonreuters.com; Editing by Mark Trevelyan)

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