A group of scientists led by Claudia Hartl published some exciting new research in April 2018. And dendrochronology, which involves analyzing tree rings and tying the rings to specific dates, was at the heart of it. The practice is also known as tree-ring dating, and it can help experts to better understand historic climatic conditions. But in an unlikely turn of events, the scientists’ research has also revealed an astonishing fact about the Tirpitz, Nazi Germany’s largest battleship.
Actually, the Tirpitz wasn’t just the largest German battleship; at the time, she was the largest battleship ever launched by a European navy. Construction started on this leviathan in 1936, and the ship’s hull was launched in April 1939 in the presence of Adolf Hitler himself.
In fact, it would not be until 1941 that the Tirpitz finally started sea trials, delayed in part by British air attacks on the Wilhelmshaven shipyard where the battleship was built. The formidable vessel was a little over 800 feet long and armed with eight powerful 15-inch guns. These were mounted in four turrets faced by 14-inch thick armor.
As well as the 15-inchers, the Tirpitz had an array of other weaponry at her disposal, including 102 guns, 58 of which were of the anti-aircraft variety. The ship was also fitted with eight torpedo tubes mounted on the ship’s sides. The image you see here was issued by U.S. Naval Intelligence to aid identification of the vessel.
The Tirpitz now became the lead ship in the German Baltic Fleet. The role of this fleet was to suppress its Soviet counterpart in the region. After Hitler attacked Russia in June 1941, the Soviets controlled only two ports on the Baltic: Leningrad (now known as St. Petersburg) and Kronstadt. The Germans had taken charge of all other ports previously occupied by the Soviet navy.
In September 1941 the Tirpitz was stood down from blockade duties and entered a period of training with her crew of 2,608. She was still on the Baltic Sea, though now based at the northern German port of Kiel. The Tirpitz might now have been deployed in the Battle of the Atlantic, a naval conflict that raged through World War II, but for one important reason.
And that was that the Bismarck, the sister ship of the Tirpitz, had been sunk by the Royal Navy after a series of fierce naval engagements in the Atlantic. And following this damaging loss, Hitler barred the Tirpitz from operating in that region. Instead, it was decided that she should be stationed on Norway’s coast. The Nazis had invaded Norway in April 1940.
The Norwegian coast, with its jagged landscape of fjords and mountains, offered a variety of hiding places even for a ship the size of the Tirpitz. Based there, German top brass reasoned, she could embark on sorties to attack British convoys sailing north to take supplies to the Soviets. Furthermore, her very presence would deter the British from any notions they might have of attacking Norway.
The Tirpitz sailed for the Norwegian port of Trondheim in January 1942. Because by then the British had succeeded in cracking Nazi codes, the Allies knew that the battleship had left Germany. However, they were unable to track her due to unfavorable weather conditions. But aerial reconnaissance identified Trondheim on the western coast of Norway as the ship’s new location.
The Tirpitz now moved north of Trondheim to Fættenfjord, a location soon revealed to the British by the Norwegian resistance. This lack of secrecy was a recurring problem for the Nazis – there were plenty of people in Norway happy to let the British know about any movements the ship made. And as a result, she was continually targeted by British air attacks.
The Tirpitz was also hampered by fuel shortages, and truth be told she now played little part in the war, with her limited sorties having little impact. Indeed, the ship’s main achievement was to force the Royal Navy to commit ships to a watching brief over her.
That said, the British continued to make determined efforts to destroy the Tirpitz. In one 1942 operation they deployed a number of two-man guided torpedoes called Chariots in an attempt to sink the ship. The Chariots, in the first operation of its kind, were shipped to Trondheim aboard a fishing boat. To keep their presence a secret, they were towed beneath the vessel for part of the journey, but in the event the torpedoes were lost in rough seas.
Fully aware that their ship was a prized target, it was essential that the crew of the Tirpitz made every effort to conceal her from the ever-present threat of attack from the air. And to achieve this, men were ordered to fell pine trees on the banks of the fjord. Branches from the trees were then festooned around the ship in an attempt to disguise her.
But the crew of the Tirpitz also used another tactic to hide her position. The Germans created clouds of artificial smoke intended to look like natural mists to hide the ship from prying eyes. The smoke was created by mixing chlorosulfuric acid and water. We’ll learn more about the impact of this smoke shortly.
Meanwhile, the British continued with their determined attempts to destroy the Tirpitz. After the failure of the Chariot torpedoes, in September 1943 they attacked their target in its fjord lair with mini submarines called X Craft. And two of the miniature craft did manage to slip past the ship’s defences and lay their mines. Needless to say, though, they failed to sink the battleship.
The end for the Tirpitz finally came in November 1944. A series of bombing raids had already damaged the ship when a final sortie by 32 Lancaster bombers sealed her fate. Between them, the bombers dropped 29 Tallboy bombs, each weighing a colossal 12,000 pounds, and scored two direct hits. The ship went down with the loss of as many as 1,200 men.
So that was that for the Tirpitz. At least until April 2018, that is. That’s when a scientific paper brought the ship back into the news. It all started when Claudia Hartl, a dendrochronologist from Johannes Gutenberg University in Mainz, Germany, began collecting tree ring samples from Norway, near where the Tirpitz had been moored for a time.
Hartl was studying the tree rings to investigate historic climate changes in the region. But during her research she came across something she couldn’t explain. Trees dating from 1945 had periods where the annual tree ring growth was entirely absent. Periods of extreme cold can impede growth, but not halt it altogether.
Moreover, one of Hartl’s colleagues knew the Tirpitz had been based near the site of her research and wondered if there might be a connection. Hartl then found archival evidence of the chlorosulphuric acid that had been used to hide the battleship. “We think this artificial smoke damaged the needles on the trees,” Hartl told the BBC. And it was quite clear that the nearer the trees had been to the Tirpitz, the more pronounced was the damage.
It turns out that this artificial smoke must have been toxic enough to kill off some of the pine needles, thus halting the trees’ growth. “If trees don’t have needles they can’t photosynthesize and they can’t produce biomass,” Hartl said. “So, if the trees lose their needles, it can take a very long time for them to recover.” More than 70 years after the sinking of the sinking of the Tirpitz, then, its foreboding legacy lives on in the surrounding woodland.