Many of the early dishwashers (Hotpoint, GE, etc.) were not automatic. They were "hands free" washing, but you had to control the fill, wash, drain, etc. manually. I have some very old service stuff from GE that details the construction and operation - it's very interesting...
I believe most of the Youngstown models were gravity drain until they came out with the front loading models where pumps were optional.
The earliest dishwasher I have is a 56 GE Mobile Maid, quite a lot of refinements since the 30's for sure, but still the performance pales in comparison to modern machines - I'm beginning to wonder though from some of the reports about new models!