As commander of U-56 he was able to avoid detection by the destroyers surrounding HMS
Nelson and came in close proximity to the British flagship, launching three torpedoes against her whilst she was carrying
Winston Churchill and the high military command of the British Navy. Following that incident he became widely known as the "Man who almost killed Churchill" amongst the U-boat submariner corps.
[3]
At 10 a.m. on 30 October 1939,
[5][6] Zahn was commander of
U-56 when he managed to avoid detection by the 10 destroyers and
battle cruiser Hood,
[7] protecting the
Home Fleet west of the
Orkneys and came within striking distance of
HMS Nelson and
Rodney.
[5]
Unbeknownst to Zahn,
[8] aboard the flagship HMS
Nelson were
First Lord of the Admiralty Winston Churchill,
[6] Admiral of the Fleet Sir
Charles Forbes, and admiral Sir
Dudley Pound who was the
First Sea Lord at the time.
[9][10] The reason for the gathering was Winston Churchill's decision to convene a conference with the leadership of the British Navy because of the sinking disaster of
HMS Royal Oak caused by a U-boat attack during which 833 servicemen died.
[8]
In Zahn's own account of the events, three cruisers were heading straight toward his U-boat's position, making any attack by him almost impossible, when suddenly they veered by twenty to thirty degrees from their previous course opening the field of attack and bringing him into a direct line of fire with HMS
Nelson and HMS
Rodney.
[5][8] Rodney was the lead ship of the convoy and Zahn decided to wait until it passed and concentrated his sights on the
Nelson.
[5] The U-boat came within the point-blank range of 800 metres of the ship and Zahn's chances of striking and sinking it were high.
[6][10]
He fired three torpedoes, from
U-56's three torpedo tubes,
[12] toward the flagship. All three struck the hull of the
Nelson but failed to explode, although the sound of the impact with
Nelson's hull was picked up by the sonar operators of
U-56.
[8][9][10][13] The third torpedo subsequently exploded at sea without causing damage.
[9] The incident has been described as the "most important non-sinking" of the conflict.
[6] After the attack Zahn became widely known as the "Man who almost killed Churchill" amongst the U-boat submariner corps.
[3]
After the attack, Zahn ordered the U-boat to descend to a deeper level to avoid depth charges since the destroyers had by now detected its presence. In the evening Zahn ordered
U-56 to surface and subsequently sent a radio report to Berlin listing the targets in the group including HMS
Rodney. The delay in the transmission of the information was caused by Zahn's depression caused by missing his target. Had this delay in Zahn's report not happened, the German command could have sent
U-58, which was in the area at the time, to renew the attack on the British targets.
[5]
Because of his failure to destroy the
Nelson, Zahn became depressed and
Karl Dönitz had felt obliged to relieve him of his
U-56 command and sent him back to Germany to become an instructor.
[13][14]
Later, in his memoirs, Dönitz called the failed attack by
U-56 "an exceptionally serious failure" but did not blame Zahn whose daring, in the presence of the destroyers, he praised, saying "The commander who had delivered the attack with great daring when surrounded by twelve escorting destroyers, was so depressed by this failure, in which he was in no way to blame, that I felt compelled to withdraw him for the time being from active operations and employ him as an instructor at home".
[13] In addition Dönitz had received reports from his men concerning problems with the defective
G7e torpedoes that they were using and knew that the failures were caused by the faulty torpedoes.
[12] Zahn eventually recovered and later that year was given command of
U-69.
[14]