COMING OF THE MOTOR SHIP.

Auckland Star, Volume LI, Issue 290, 4 December 1920, Page 17

COMING OF THE MOTOR SHIP.

FUNNELLE-S VESSELS OF THE

FUTURE.

1 Many years ago I chronicled early experiments in Holland and Germany with Diesel engines fitted to fishing boats, writes Mr. R. P. Hearnc, in the

"Sphere." These motors, whilst of the internal-combustion type, differed from the engine of a motor car in that heavyoil was used instead of petrol, and the oil was burned by being mixed with heated and compressed air instead of being ignited by a sparking plug- Air drawn into the cylinders is compressed by the pistons to a high pressure, and the effect of this compression is to raise the temperature of the air to such a degree that the oil injected is readily burned. The oil may be delivered either in a spray or in a "solid" stream. Compressed air is used for injecting the oil and also for starting purposes.

Extraordinary progress has been made in I.C. (internal -combustion) marine engines since that time, and we have many different forms apart from the Diesel. But for ocean-going ships requiring powerful engines the most favoured ioiui of motor is sonic adaptation of the Diesel. A highly interesting comparison of the three forms of engine has been worked out in the case of a standard cargo vessel of 9000 tons with 3000-h.p. engines. Here are the results: (a) Steam engine with coal, 3o tons of coal per day used; (b) steam engine, oil-fired, 22 tons of crude oil per day: (c) marine oil engine, 9 tons of crude oil per day. Thus, compared with coal, the actual daily fuel load is reduced from 36 to 9 tons, and in addition to weight saved there is the still more valuable feature of space economised. The motor ship gives a very striking example in term-, of money.to show the economy of th* marine motor. Freights to South Africa are to be increased by 10/ per ton,

mainly due to the rise of Welsh coal from 65/ to 105/ per ton. A steamer carrying 5000 tons of cargo and burning 1250 tons of coal would inciir an extra fuel bill of £2500 on this acpount. Were this ship fitted with oil engines it •would only burn 310 tons of oil at £5 per ton.

Furthermore, the motor ship woulct save £150 per voyage owing to the smaller engine-room staff required, and from 5 to 10 per cent more cargo; that is, from 250 to 500 more tons of cargo could be carried. These figures establish on paper the superiority of tlie motor ship, but, we may ask, what is the actual position? Is the oil motor fully tested on the grand scale? To this I reply that the test of actual experience 16 now being made by many builders, and I am very pleased to see that British engines are well to the fore. At the moment, however, the largest motor ship afloat is the Danish ship Afrika, but we may soon expect to beat her records. The Afrika is a 13,000-ton vessel, 445 ft long and 60ft beam. Her oil engines, built by the famous firm of Burmeister and Wain, develop 4500 h.p., and burn only 14 tons of oil per day as against 30 tons of oil on an oil-fired steamer, and 50 tons of coal for an ordinary steamer of the same size and power. The reader will be specially interested in the good appearance of this motor ship, which is destined to set a new fashion in marine architecture. The most striking innovation is the abolition of the funnels. This alone will have a profound effect on naval design also, for the funnelless ship will have a marked influence on strategy. With the funnels disappear the smoke, and the oil warships of the future will be structures that will make of sea scouting n fin.? art. No longer will tell-tale smudges and trails of smoke on the horizon betray the position of vessels.

In the Afrika tll- exhnust gases from the engines arc taken away'by pipes, which arc seen alongside the third mast! In the coming motor warships the masts doubtless can be telescoped or reduced to mere stumps, and the exhaust pipes will he carried low down nt tii- stern. Possibly the next staee will be the submersible big ship. The engines of the

Afriga are worth particular study. So compact is the power plant that the engine-room is only 45ft long, and yet plenty of space is allowed. Two banks of motors are installed, each of 2,250 h.p. On her trials the Afrika maintained an average speed of 13 : } knots. The total loading capacity is 772,300 cubic feet. Her fuel-oil capacity is 1470 tons, which gives a radius of action of 30,000 sea miles.

The illustrations show also a monster engine, the 3,200-h.p. Diesel engine, built for the Glenapp, of the Glen Line. On the right-hand side of the illustration will be noted a small auxiliary engine of similar type, and the difference between the two will show the very wide .range of size which'already exists in oil engines. Messrs. Vickers, Ltd., are •building the 10,000 ton Narragansett for the Anglo-American Oil Co., and generally it may be said that great activity is being shown in this new movement. The 6000 ton motor ship Salerno is notable for the completeness of its electric installation, the only steam boiler on the ship being a small one for heating the cabins. On the later ships even this is <i>eing dispensed with.