As I said, I was looking for something Disney-related on YouTube. I didn’t find it, because Disney’s official online copy of “Steamboat Willie” not only looks terrible, it’s the censored version.
Here is a complete, uncensored copy, in much better quality. It appears to have been taken from the “Mickey Mouse in Black and White” DVD.
Mickey enjoys piloting the boat, but he isn’t the captain and he’s put to work. Instead, he sneaks his girlfriend on board and proceeds to goof off, not doing his job while having fun torturing animals. After the end of the cartoon Mickey probably made Minnie peel the potatoes.
The great Ub Iwerks was the lead animator, even the only animator, on the earliest Mickey cartoons. It’s safe to assume that Ub also designed the original Mickey. This PDF about “Steamboat Willie” at the Library of Congress was written by the late Dave Smith, who was Disney’s first archivist.
https://www.loc.gov/static/programs/national-film-preservation-board/documents/steamboat_willie.pdf
After years of Congress bending to Disney’s demands to extend the “Steamboat Willie” copyright, as of January 1 it will finally be in the Public Domain.