Wiktionary
register tons
n. (plural of register ton English)
Usage examples of "register tons".
The students wanted to know how many Spitfires you had to shoot down, how many gross register tons you had to sink.
German submarines in the First World War: Weddigen and the U9, submarine plays decisive role in Dardanelles campaign, sinking a total of thirteen million gross register tons.
But the Smeaton being only about forty register tons, her accommodations were extremely limited.