In two patrols she sank one merchant ship , for a total of 1,926 gross register tons ( GRT ) , one warship sunk ( 1,300 tons ) .
One merchant ship damaged ( 6,991 GRT ) .
In two patrols she sank one merchant ship , for a total of 1,926 gross register tons ( GRT ) , one warship sunk ( 1,300 tons ) and one merchant ship damaged ( 6,991 GRT ) .