The German navies—the Kaiserliche Marine, the Reichsmarine, and the Kriegsmarine—all planned to build aircraft carriers, though none would ever enter service. These ships were based on knowledge gained during experimentation with seaplane tenders operated by the Kaiserliche Marine during World War I. Among these were the light cruiser SMS Stuttgart, which was converted to carry three seaplanes, and the armored cruiser Roon, which was to have carried four. These ships did not meet the needs of the High Seas Fleet, however, and so a more ambitious plan to convert the unfinished passenger liner SS Ausonia into an aircraft carrier was proposed in early 1918. The project could not be completed before the war ended in November, however, as resources could not be diverted from the U-boat campaign