When we compare a tanker of 250,000-dwt (deadweight ton) with one of 25,000-dwt, we notice that the horsepower propeling the big ship is not anywhere near ten times the horsepower of the ship that is ten times smaller. In fact, it may be less than three times as much, and yet, the relatively low horsepower can give the VLCC (very large crude carrier) the same speed at sea as the smaller tanker.
