A CLAN LINER OF 6,843 TONS GROSS, the Clan Macdougall is driven by an eight-
YEAR by year the tonnage of motorships under construction and in service is steadily mounting, and it is possible that eventually the oil engine will dominate the trade routes of the world.
The application of oil engines to use in the Mercantile Marine is worthy of special consideration. There are many different classes of vessel covered by the term “motorship”, and every type has its special uses and its advantages over steam-
Apart from the special purposes for which oil-
The steam marine engine was tried out in many forms before the vertical type, with inverted cylinders, was adopted as standard for screw-
The first, large diesel-
The liner is propelled by quadruple screws driven by four sets of Sulzer diesel engines, each of 3,000 brake horsepower, with cylinders of 27½-
Between these platforms there is usually a distance of 8 to 10 feet. Forward of the main engine-
The driving of auxiliaries in a motorship presents a number of problems peculiar to the operation of oil engines. In some smaller types of diesel engine the compressed air used for starting and manoeuvring is obtained from pumps driven by the main crossheads. Where two-
In the Aorangi the scavenging air is supplied by a set of three turbo-
Steam is used for driving some of the bilge-
The presence of steam boilers in a motorship requires some explanation, although their use is now confined principally to motor tramps and tankers. In such instances, one reason for the use of steam to drive auxiliaries is that some of the waste heat from the engines can be used in the boilers. In these circumstances the boiler is started up by burning oil fuel in the furnaces and
THE FIRST DIESEL ENGINED LINER of considerable size was the Aorangi, built at Glasgow in 1924, for the service between Vancouver and Australia. A quadruple screw vessel of 17,491 tons gross, she is propelled by four sets of Sulzer six-
In motor passenger ships steam was formerly used for cooking, heating domestic water and air-
In addition to passenger liners, another type of motorship that is generally provided with steam plant for auxiliary purposes is the oil tanker. In vessels of this type the pumps for handling the oil are most conveniently driven by independent steam engines. Further, the oil cargo in cold climates becomes viscous and difficult to pump. To overcome this difficulty coils of piping are placed in the cargo tanks and steam is used to heat them.
There is another, and rather unusual, reason for using steam in motorships, especially those engaged in the oil trade. In ships propelled by diesel engines there must be a supply of compressed air for starting. Compressed air was once used for driving turbine-
The Aorangi has accommodation for nearly 1,000 passengers and some 330 officers and crew. It is the passengers that have decided the rather vexed question of funnels. A ship is not a ship without a funnel in the estimation of the average traveller by sea. But funnels in motorships appear to be used for almost any purpose but the discharge of smoke.
In a diesel-
In the passenger liner Aorangi we have seen the method adopted in arranging the four engines for the driving of quadruple screws. Other types of ships, however, call for different arrangements in the engine-
The space problem occurs in an acute form where the machinery is placed right aft, as in oil tankers and other ships that carry cargo in bulk. By choosing the more compact types of engine, however, difficulties involved in arranging the engines and auxiliaries can be overcome. In some ways the motorship with engine-
There is one factor in ship propulsion that sets a problem for the marine engineer. The marine steam turbine, for example, must run at a high speed to attain its maximum efficiency. The most efficient speed for the screw propeller is considerably lower, and the difference between the two speeds is overcome by the use of gearing. Similarly in motorships gearing has been used to supply the transmitting medium between the source of power and the ship’s propeller.
The use of mechanical transmission in the form of gearing has a number of advantages for motorships. In the first instance the use of gearing gives the necessary reduction in engine speed. A number of comparatively small high-
THE FIRST BRITISH DIESEL-
In addition to gearing there are two other principal methods, apart from direct drive, of transmitting the engine power to the propeller. Either method, generally used with gearing, is equally applicable to steam or internal combustion engines. One system uses a fluid as the “connecting link” between the engine and propeller. The other system is electric. One fluid transmission system uses a combination of gearing and hydraulic clutches that serve also as a means of reversing where non-
It is the electrical system of transmission, however, that has been adopted for marine use, not only in motorships, but also in some of the largest vessels powered by steam turbines. Among such ships equipped with steam turbines are the Normandie and a number of large warships in the United States Navy. Diesel-
Among the first electrically propelled ships was the Electric Arc, equipped in 1911 for demonstration purposes. The vessel was 50 feet long and was fitted with an internal combustion engine, of 45 brake horse-
Valuable data were obtained from the trials of the Electric Arc, and in 1913 a much larger vessel was fitted with diesel-
There are many applications of the oil engine and motorships comprise all types of vessel from ferry boats and tugs to shallow-
A MODERN MOTOR VESSEL of 6,588 tons gross, the City of Lille was built at Glasgow for the Ellerman Lines. She is driven by a four cylinder diesel of the two-
Another type of ship to which the oil engine has been applied successfully is the coasting vessel, and many coastal motorships are to be found in all parts of the world. The diesel engine has come into prominent use in Holland for shallow draught vessels on the canals and on the Zuider Zee. An interesting motorship of this type is the W. F. van der Wyrk, 202 feet long, but with a draught of only 6 feet. She is fitted with two 500 brake horse-
The tug is yet another type of ship in which the diesel engine is being fitted, especially in Holland and Germany. An 80-
Many famous private yachts are powered by diesel or semi-
One of the first motor-
Another early motor vessel was the tanker Vulcanus, owned by the Asiatic Petroleum Company, and this little ship of 1,179 tons gross, built in 1910, has been scrapped. It is, however, only her hull which was worn out through the continued carriage of crude oil distillates. The engines are still functioning perfectly in a power station ashore.
Some of the earliest motor vessels of all ran on the River Volga. These well-
A DANISH MOTOR VESSEL of 6,153 tons gross, the Jutlandia, was built in 1934. She is a twin-