> ... logarithmically proportional to the size of the vesel. A ship that is twice as big will only require and engine that is half as big. Surely not "half as

> ... logarithmically proportional to the size of the vesel. A ship that is twice as big will only require and engine that is half as big. Surely not "half as big". ITYM the engine size for a 2x vessel size increase is 1.5x. Maybe "half again as big" would convey it.