'Baldur' was one of several German convoy operations associated with a major evacuation effort in the Black Sea to remove the remnants of the 17th Army (5/12 May 1944).
Despite the Soviet pressure on General Karl Allmendinger’s 17th Army holding Crimea at this time, Adolf Hitler had initially refused to consider an evacuation of this formation, now isolated in Sevastopol, until General Polkovnik Georgi F. Zakharov’s 2nd Shock Army (attacking in the northern sector from 5 May) and then General Leytenant Yakov G. Kreizer’s 51st Army and General Polkovnik Andrei I. Eremenko’s Separate Coastal Army had broken through to the Sapun Heights on 8 May. Only then did Hitler, in response to further appeals, order the evacuation of the hard-pressed remnants of the 17th Army, which had possessed a strength of 264,700 men on 3 May.
At this time the German and Romanian naval strength supplying and supporting the 17th Army comprised the transports Oituz, Ardeal, Alba Julia, Budapest, Danubius, Prodromos, Helga, Ossag, Geiserich, Kassa, Totila, Teja, Tisza and Durostor, three KT ships, large numbers of tugs, and the ferry barges of Kapitänleutnant Max Giele’s 1st Landungs-Flottille, Kapitänleutnant Herbert Kuppig’s 3rd Landungs-Flottille and Korvettenkapitän Bernhard Stelter’s 7th Landungs-Flottille.
Under the overall command of Vizeadmiral Helmuth Brinkmann’s Kommandierender Admiral Schwarzes Meer command, escort was provided by Kapitän Kurt Weyher’s 10th Sicherungsdivision. The Romanian naval forces were led by Contraamiral Horia Marcellariu. The warships committed to the enterprise were the Romanian destroyers Regina Maria, Regele Ferdinand, Maresti and Marasesti, Romanian gunboats Ghigulescu and Stihi, Korvettenkapitän Arthur Gampert’s 1st Unterseebootsjagd-Flottille (UJ 103, UJ 104, UJ 106, UJ 115, UJ 116 and UJ 117), Oberleutnant Dr Alexander Reichmann’s 3rd Unterseebootsjagd-Flottille (UJ 301 to UJ 307, UJ 310 and UJ 313 to UJ 318), Korvettenkapitän Gustav Wolters’s 23rd Unterseebootsjagd-Flottille (UJ 2305, UJ 2307, UJ 2302, UJ 2312, UJ 2313 and UJ 2318) and Kapitänleutnant Helmut Klassmann’s 3rd Räumboots-Flottille (R 35, R 37, R 164, R 165, R 163, R 166, R 196, R 197, R 203, R 205, R 206, R 207, R 216 and RA 54). Flanking escort was the task of Korvettenkapitän Hermann Büchting’s 1st Schnellsboots-Flottille (13 craft).
Despite the large scale of the Soviet deployment of aircraft and submarines, the German and Romanian warships and transports were able to evacuate 37,500 men by 13 May, including 25,677 troops and 6,011 wounded in the last three days. In the process, UJ 2310 and UJ 2315 had to be run aground. As a result of attacks by General Polkovnik Konstantin A. Vershinin’s 4th Air Army and General Leytenant Timofei T. Khryukin’s 8th Air Army, the losses among the transports and warships were heavy, and included the 2,773-ton Totila, 3,600-ton Teja, 2,200-ton Helga, 1,489-ton Danubius and 800-ton Prodromos, the 3,152-ton minelayer Romania, the submarine chasers UJ 2313, UJ 2314 and UJ 310, three auxiliary vessels, five tugs, 11 lighters and several other small craft. Among the transports, the 1,309-ton Durostor and 712-ton Geiserich were damaged by bombs: the latter was towed to Constanța in Romania, where she sank on 12 May, and the former sank as a result of the damage she had received.
Most of the Soviet submarines remaining in the Black Sea were deployed at this time. L-4, Shch-201 and Shch-202 were still at sea, A-5, M-35, M-62 and M-111 were once more sent out on patrol, and M-54 and S-33 were deployed in the area between Sevastopol and the Romanian coast.
On 6 May Shch-201 attacked the 'Baldur' convoy to the south-west of Cape Tarkhankut and missed KT-26. On 7 and 8 May Shch-202 attacked and missed three small vessels off Sevastopol. On 11 May M-35 missed the 'Tanne' convoy, and on the same day L-4 attacked the 'Astra' convoy off the Romanian coast. The submarines returned to their bases during the middle of the month. In all, 130,000 German and Romanian troops were evacuated by sea and 21,457 by air between 12 April and 13 May; 78,000 were left behind as prisoners or dead, and of the troops on the transports which were sunk, 8,100 could not be rescued.