The total number of crew employed on the Vukanus was sixteen, and the cost of running a day amounted to £6 6s. 5d., compared with a staff and crew of thirty for the coal-burning vessel, and a cost of £9 Os. 7d. a clay.
At the present time, a vessel of 10,000 tons deadweight capacity, and fitted with Diesel engines equalling 6,600 horse-power, makes a speed of 14 knots—a remarkable achievement, considering the comparatively short period this type of internal combustion engine has been adopted for marine purposes. Concurrently with this, of course, a considerable economy has been effected in fuel con sumption, which naturally varies, according to the B.T.U. obtainable from the oil used, and the size of the engine employed. A 13-knot ship attained an average speed, loaded, over a long voyage, of 1l•7 knots, on a fuel consumption of 12.2 tons of fuel oil. The maximum cargo carried, including 1,300 tons of oil, amounted to 9,400 tons ; her cruising radius was 120 days at a speed of 13 knots. The fuel consumption in i.h.p. worked out at 133 grammes.
The following table sets out concisely the speed and fuel consumption of early and recent motor ships— It was considered in the early days of the Diesel engined ship that the engines would not be able to drive vessels of large size, but it will be noticed that a rapid increase is taking place in the tonnage of the motor ship, and that a higher speed is now attainable on a lower End consumption. One of the largest ships yet con
structed, the Gltniffrr, has a deadweight capacity of 10,000 tons, and is equipped with two sets of Diesel engines, having a combined power of 6,600 h.p. It has been estimated that this vessel can make 14 knots, and will be capable of running from London to Australia, and make more than half her return voyage without replenishing her oil supplies. The advantages of such a feat are obvious, both from the shipping company's point of view and from that of the trader. The motor ship, indeed, fulfils one of the vital conditions so essen tial to successful trade, namely, rapidity of transit, due not only to its speed, but to the fact that bunkering is eliminated during the voyage, which enables the vessel to arrive at its destination ahead of a steam-driven ship of even higher speed, and starting from port at the same time.
In order to express the various economic advantages attaching to the use of the motor ship I cannot do better than reproduce a table (shown on the opposite page) which was included in a paper read by Mr. James Richardson, of Messrs. William Beardmore & Co., Ltd., before the Institution of Engineers and Shipbuilders of Scotland, comparing the running costs of a Diesel ship with those of steam ships of 1,000 b.h.p. in each instance.