Horst Bredow of the German U-boat Archive has records of 1,171 U-boats having been commissioned between 1935 and 1945. If one combines this figure with the famous Churchill comment the the only thing that frightened him throughout the war was the U-boat threat, then it is easy to conjure up visions of hundreds of bloodthirsty U-boat commanders prowling the waters around the British Isles and along the eastern seaboard of the United States. However, the figure of 1,171 boats is grossly misleading, and does not reflect the reality of the war at sea. The number of Allied ships which were attacked and at least damaged can be calculated from Axis Submarine Successes by Dr. Jürgen Rohwer. The details for the Atlantic and North Sea are as follows:

25 U-boats attacked, sunk, or at least damaged 20 or more ships
36 U-boats attacked between 11 and 19 ships
70 U-boats attacked between 6 adn 10 ships
190 U-boats attacked between 1 and 5 ships

This adds up to a total of 321 U-boats. Ships sunk in the Black Sea, Mediterranean, Baltic, and Indian Ocean will make the total rather higher, and one could allow a few more for calculation errors. However the probable total still leaves a staggering gap of about 850 U-boats which appear not to have sunk or damaged anything throughout the entire war. In fact almost all of these, representing three-quarters of the whole U-boat Arm, never came within shooting distance of the enemy. School boats, supply boats, experimental craft, and boats commissioned towards the end of the war which were never in a position to sink ships, could be discounted; but there still appears to be a huge discrepancy between the number of U-boats commissioned and the number which actually attacked the enemy. This makes one wonder why Germany put so much effort and so many resources into building submarines, if the majority never achieved anything other than tying down the vast enemy forces which hunted and destroyed them.

It might be worth adding that these figures were not calculated with hindsight: they were available to U-boat Command at the time, and the only difference between then and now is that we now know that U-boat commanders generally overestimated their tonnage sunk by about one third.

Looking at the same figures from a different angle, one might consider that these ships were sunk by men rather than by machines. Out of a total of about 2450 Allied ships sunk in the Atlantic one finds that 30 U-boat commanders were responsible for sinking just under 800 of these. This means that 2% of the U-boat commanders were responsible for sinking almost 30% of the Allied shipping losses in the central area of the submarine war.