U-Boats in the Black Sea
Last week I examined the U-boat war in the Arctic. This week I'd like to turn your attention roughly 2,000 miles to the south. There in the Black Sea, the Soviet Navy faced off against the Axis powers in a poorly understood war that nevertheless featured: amphibious landings, to big-gun fire support for ground forces, convoys, sea-control, sea-denial, anti-ship, ASW, mine, and submarine warfare.
In this article we shall look at the battle beneath the waves. More specifically, how the Germans employed U-boats in the Black Sea, and to what extent those U-boats proved effective - or not. Before we can do that however, we first have to set the stage for the arrival of the U-boats. The Black Sea, far from being a distant backwater of the war, proved important to the fighting on land in the Ukraine, Crimea, Southern Russia, and The Caucuses. When Barbarossa began in June 1941 the Soviet Navy ranked as the dominant seapower in the Black Sea deploying: one battleship, five cruisers, fifteen destroyers, eighteen minesweepers, and a whopping fourty four submarines and eighty four motor torpedo boats (MTB's). In comparison, the Romanian Navy served as the primary Axis surface fleet in the region - with a mere four destroyers, six fleet torpedo boats, seven MTB's, two minelayers, one submarine, and five midget submarines.
It's perhaps no surprise then that the Soviet Navy had an outsize influence on the fighting along the Black Sea's coast during 1941. In particular, the Soviet fleet played a key role in allowing the city of Odessa and it's large garrison of nearly 90,000 men to put up a protracted resistance before succumbing to the Axis assault. Even then, the Soviet Navy evacuated a large number of Odessa's defenders, and they along with the Soviet Navy subsequently helped stop initial Axis efforts to take Sevastopol. From there, the Soviet Navy conducted a number of amphibious assaults that in December of 1941 led to the Red Army's recapture of the Crimean Kerch Peninsula. Axis forces were unable to evict the Soviet army, supplied throughout the winter by the Red Navy, until the spring of 1942. Meanwhile, Soviet submarines operating along the Bulgarian and Romanian coast sent nearly 30,000 tons of Axis shipping to the bottom; albeit at the cost of five Soviet submarines lost to Romanian minefields (out of a total of 15 submarines Romanian minefields claimed by the war's end).
The Germans realized they could not let the Soviet Navy continue to be a thorn in Army Group South's side. Though German airpower took the largest toll on Soviet shipping and naval operations the Germans knew that to control the Black Sea they would need to get warships into it. Therein was the problem. The Montreux convention of 1936 had granted Turkey control over the Bosporus straights guarding entry into the Black Sea from the Mediterranean. Though Germany hardly had any problems violating treaties (with Barbarossa itself perhaps the biggest such violation) the Germans were loathe to force or induce Turkey (a neutral power during World War II) to allow the passage of Germany's most effective naval weapon into the Black Sea: Type VII U-boats. The Germans feared that in doing so the large British fleet could enter the Black Sea and make life even more difficult for the Axis powers. As such, Germany turned to a solution first employed during World War I: overland transport of submarines (during WWI accomplished by rail to the Adriatic).
Once again, and just like in the Baltic operations during Barbarossa, Germany turned to the recently retired Type II coastal U-boat fleet: in this case chosing three Type IIB U-boats then in service as training boats off the Prussian coast. Displacing 275 tons surfaced the Type IIB could make thirteen knots on the surface, and seven submerged, with a cruising range of just over 3,000 miles on the surface and about forty miles submerged. As previously mentioned the Type IIB carried only a modest armament of five torpedoes (or a single torpedo and nine mines) capable of being fired from three torpedo tubes. All told, Germany commissioned 20 Type IIB's during the war - six of which served with the 30th U-boat flotilla in the Black Sea.
Transporting the U-boats to the Black Sea proved a complicated process. The Germans first stripped down the U-boats in Kiel and then mounted the hulls on rafts floated through the Kiel canal and up the Elbe to Dresden. From there, they put the U-boats on trailers towed by powerful Kuhlemeyer trucks to Ingolstadt on the Danube River. There, the Germans returned the U-boats to rafts and used tugs to pull them to Galati, Romania. Reassembly took just over a month and thus a process that began in April of 1942 did not end until October of 1942 when U24 became the first German U-boat to sail operationally in the Black Sea. The Germans also sent down the Danube over 30 S-boats and R-boats as well as a myriad number of other light ships to also fight in the Black Sea. Unfortunately for the Germans, and in part due to their late arrival in the region, the U-boats were able to accomplish very little toward influencing the war during the critical year of 1942. By late 1944 the 30th flotilla had sent to the bottom just over 45,000 tons of Soviet shipping (with most of this damage done during 1943) but by September of 1944 the Red Army was sweeping through the Balkans. All six Type IIB U-boats of the 30th flotilla were subsequently scuttled - three off the Romanian coast and three along the Turkish coast. The Turks interned the crews for the remainder of the war.
The concept of using Type II U-boats in the Black Sea was a sound one. However the U-boats never proved the equal to German airpower in terms of damage caused to Soviet shipping. Moreover, due to the small size of the U-boat commitment they proved unable to effectively interdict Soviet shipping and influence operations on land. One can only wonder what might have been had the Germans reacted with more alarm and urgency to the Soviet Black Sea fleet's success during 1941. By October of 1941 it was clear that Barbarossa had failed to knock the Soviet Union from the war in a single campaign, and the Soviet Black Sea fleet had played a key role in slowing Army Group South's march east. Yet the decision to send U-boats to the Black Sea was not made until the spring of 1942 - far too late to matter with too few of these useful coastal U-boats dispatched to the region. Yet again, the German decision to overemploy available assets in strategically secondary theaters (such as U-boats in the Arctic) cost them in Southern Russia and the Black Sea littoral during the Second World War's most important campaign.