By designing the hull correctly, its resistance to forward movement can be reduced significantly and its overall energy economy will be improved. The design of the bows is of special importance. The bulb changes the flow of the waves round the hull in such a way the tugging resistance is reduced. When ships are designed today, model ships in a tugging tub constitute an important designing tool. Transport by ship is by far the cheapest form of transportation if we measure the consumption of energy per amount of goods shipped.
Air transportation is about one hundred times more expensive.