The movies wiki https://en.wikipedia.org/wiki/Space_Battleship_Yamato
The movies title (宇宙戦艦ヤマト) write Yamato (ヤマト) as katakana. However, Yamato is Japanese word, which is available in Kanji (大和).
大和 also the name of Yamato Battleship. (https://en.wikipedia.org/wiki/Japanese_battleship_Yamato)
As I learned that Katakana use for foreign word, technical word, sound, ...