Interwar roots of landing-ship dock design

How early could well-deck landing ships have been designed into naval forces?

British and American studies pointed toward landing-ship dock concepts by the 1920s and 1930s, with earlier ideas likely circulating before formal designs became viable.

A British study in the 1920s and a related American design path led toward the first generation of landing-ship docks. Formal studies usually follow a longer period in which an idea circulates through institutions. Institutional discussion may reach back toward the 1910s, although the technology became moderately viable in the 1920s. If war had come later, Britain might have built serious landing ships before 1942 as part of Far Eastern planning.