tonnage
Refers to the capacity or weight of a ship measured in tons, or the total amount of cargo in tons.
The tonnage of this ship is 50,000 tons.
Standard kanji spelling for tonnage.
Common variant using katakana for トン.
Mixed kana-kanji spelling.
噸 is a kokuji (Japanese-created kanji) for 'ton', combined with 数 (number/amount).