Incidentally, in the version of TOS dubbed in Japanese, Sulu is changed to Kato. And Scotty becomes Charlie for some reason.
Easier to pronounce in Japanese, probably. The "-ty" part wouldn't be pronounceable in Japanese; the corresponding syllable is pronounced "chi." So it would be sukachi
, which would basically sound like "Scotchy."
And they made up their own stories, and Kato was kind of the boss.
I think that's a myth. Shatner once joked on Saturday Night Live
that the Japanese name for the show is Sulu, Master of Navigation
, and that joke has been misreported as a fact in a number of places. (It's actually Uchuu Daisakusen
, "Major Operation in Space," which is a reasonably literal translation of Star Trek
. Although in the movies it's generally just transliterated as Sutaa Torekku