the Adriatic was done with little to no opposition from the Allied Powers. American planning for a naval offensive to sweep the Adriatic and even land up to 20,000 marines with naval and infantry support from Britain, France, and Italy were halted by the onset of the German spring offensive in France, launched on 21 March 1918. Horthy used these first few months as Commander-in-Chief to finish his re-organization of the navy. As one of Njegovan's final actions before he was ousted entailed shifting several smaller and older vessels around to different ports under Austro-Hungarian control, the only ships which remained at port in Pola aside from the three of the Radetzky class were the four dreadnoughts of the Tegetthoff class, which had now fallen under the command of Captain Heinrich Seitz. Horthy worked to re-locate as many ships as he could back to Pola in order to maximize the threat the Austro-Hungarian Navy posed to the Allied Powers. Horthy also used his appointment to take the Austro-Hungarian fleet out of port for maneuvers and gunnery practice on a regular basis. The size of these operations were the largest the navy had seen since the outbreak of the war. These gunnery and maneuver practices were conducted not only to restore order in the wake of several failed mutinies, but also to prepare the fleet for a major offensive operation. Horthy's strategic thinking differed from his two predecessors, and shortly after assuming command of the navy he resolved to undertake a major fleet action in order to address low morale and boredom, and make it easier for Austro-Hungarian and German U-boats to break out of the Adriatic into the Mediterranean. After several months of practice, Horthy concluded the fleet was ready for a major offensive at the beginning of June 1918. Otranto Raid Horthy was determined to use the fleet to attack the Otranto Barrage. Planning to repeat his successful raid on the blockade in May 1917, Horthy envisioned a massive attack on the Allied forces with his four Tegetthoff-class ships providing the largest component of the assault. They would be accompanied by the three ships of the Erzherzog Karl-class pre-dreadnoughts, the three s, the cruiser Admiral Spaun, four s, and four torpedo boats. Submarines and aircraft would also be employed in the operation to hunt down enemy ships on the flanks of the fleet. On 8 June 1918 Horthy took