POLISH divers have discovered the rusting wreckage of Nazi Germany’s only aircraft carrier, the Graf Zeppelin, solving one of the most enduring maritime riddles of the Second World War.

For more than half a century the location of the huge vessel was kept secret by the Soviet authorities. Even the opening of the Moscow archives in the 1990s failed to produce a precise bearing. The once-proud ship was simply one of dozens of wrecks that littered the bed of the Baltic Sea near the Bay of Gdansk.

“We were carrying out soundings for possible oil exploration,” Krzysztof Grabowski, of the Petrobaltic exploration group, said. “Then we stumbled across a vessel that was over 260 metres (850ft) long at a depth of 250 metres.”

Divers confirmed this week that it was the German ship, though who owns her and what — if anything — will happen to her remains unclear.

When the Graf Zeppelin was launched in 1938, Adolf Hitler raised his right arm in salute to a warship that was supposed to help Germany to become master of the northern seas. But, when fleeing German troops scuttled her in April 1945, she had never seen service — a casualty of infighting within the Nazi elite and the changing tide of war.

The Graf Zeppelin was scuttled in shallow water near Szczecin and it proved easy for the Red Army to recover her after marching into the Polish port. According to an agreement with the Allies, German and Japanese warships should have been sunk in deep water or destroyed. The Russians repaired the ship, then used her to carry looted factory equipment back to the Soviet Union. In August 1947 Allied spies observed her being towed back to the Polish Baltic coast and then used for target practice at Leba by Soviet dive bombers. It appeared that the Russians were preparing for possible action against US aircraft carriers.

The Graf Zeppelin sank a second time, and remained undetected until now.

Lukasz Orlicki, a Polish maritime historian, said: “It is difficult to say why the Russians have always been so stubbornly reluctant to talk about the location of the wreck. Perhaps it was the usual obsession with secrecy, or perhaps there was some kind of suspect cargo.”

At 262 metres, the Graf Zeppelin was comparable to the biggest of the US carriers that played such a significant role in the Pacific. She had a range of 8,000 nautical miles, meaning that she could easily have reached the North Sea.

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