Although it's not the right answer, I felt that it's worth pointing out that what you've described is basically the plot-line of an episode of Red Dwarf entitled "Dimension Jump", in which 'Ace' Rimmer uses an experimental spaceship to travel interdimensionally.
On his first mission he encounters Arnold Rimmer and is disgusted by him. After some comparison it's revealed that their lives diverged when 'Ace' was held back a year in school.
A Rimmer from an alternative universe, known to his friends as Ace,
test pilots an experimental spacecraft for the alternative Space
Corps. He arrives in our universe, where he crashes into Starbug
which is forced to land on the surface of a desolate water planet.
Ace, seeing their predicament, comes to their rescue.
Smoke me a kipper, I'll be back for breakfast!