Early WWII U-Boats at Sea - 1939

Despite the initial successes the U-boats were able to claim in their war on trade – and these were not insignificant in themselves – the results would have been even more dramatic if they had not suffered from repeated equipment failures. Torpedoes could not be entirely relied upon to run at the requisite depth and even if they did, too many didn’t explode on impact or did so prematurely. It was deeply frustrating for the U-boat captains. They could manoeuvre their way into position to both close the range and get a clear uninterrupted shot at an enemy ship, fire their torpedoes and still not register a hit on the targeted vessel. It wasn’t complacency that held up improvements in these areas of concern, for the recurring problems of depth keeping and unreliable detonators were addressed by German naval engineers from early on in the campaign. Much to Dönitz’s agitation, developmental research programmes geared to rectifying torpedo problems were unable to provide a more effective alternative for many months to come. Even so, the stealth of the U-boat, the degree of success it was already achieving in sinking merchant shipping, and the relative difficulty that the Allies had in finding and destroying them were all key advantages that were not lost on the OKM or on Hitler. U-boat construction became a matter of the highest priority as could be seen in the cancellation of six battleships, three battlecruisers, an aircraft carrier, four light cruisers and twelve destroyers before the end of September and the freeing up of resources in the naval dockyards so that sixteen small coastal submarines (Type IID) and fifty-five ocean-going U-boats could be built in their stead. By the end of October another sixty of the larger workhorses destined for operations in the Atlantic would be ordered as well.

Whatever Raeder and his contemporaries from the old naval school might have thought about the merits of the surface fleet, the overall utility of the Uboat could hardly be denied. Despite being much slower and less powerful than any of the main types of surface warships, the submersible in the hands of an expert was still capable of being used with flair. Gunther Prien’s dashing act of impertinence in penetrating the vulnerable main base of the Home Fleet at Scapa Flow in U47 and sinking the battleship Royal Oak in the early hours of 15 October proved this beyond all doubt. To add salt to the Admiralty’s wound, Prien had then escaped unharmed through the same porous defences. His heroic exploits won him instant acclaim, added immeasurably to a cause that Hitler increasingly identified with, secured a further promotion for Dönitz, and underlined the wisdom of investing in such a relatively small, cheap and easily built craft.