348 



NATURE 



[September i6, 1909 



carrying c:ipaciiy is relalively small ; but the law of in- 

 crease in size and cost is obeyed, and will be followed up 

 to the hii.it which may be fixed by Hie va^t oatlay neces- 

 sary in Older to provide suitable haibouis and dock 

 accommudation wilh an adequate depth ol water, or by 

 connmeiiial considerations and the possibility of securing 

 a suitable return on the large capital expenditure. Growth 

 in 'Imensions of ships will not be determined by the naval 

 aichitect and marine engineet finding it impossible to go 

 further, for there aie even now in view possibilities of 

 further progiess if the shipowner so desires. Invention 

 .^nd improvement have not reached their ultimate limits. 



The wonderful progress made during the last seventy 

 years is well illustrated by the history of shipping trading 

 between Canada and Great Britain, and it may be of 

 interest to recall a few of the principal facts. For a long 

 period trade and communications were carried on by wood- 

 built sailing ships, many of the finest being Canadian 

 built; but at a very eariy period Canadians had under 

 consideration the use of steamships. One of the first 

 steamers to cross the Atlantic was the Royal William 

 paddle-steamer, built near Quebec in 1831. She was 160 

 feet long, 44 feet broad, of 363 tons burden, sailed from 

 Quebec on August 5, 1S33, and reached Gravesend on 

 September 16, a passage of more than forty days, in the 

 course of which sail-power was largely used. Cabot, in 

 1497, crossed in the good ship Matthew, of 200 tons 

 burden, which was probably from 90 to 100 feet in length; 

 so that three centuries of progress had not made very 

 great- changes in size of the ships employed. Wood was 

 siill the material of construction, and sails were still 

 used as a motive power, although the steam-engine was 

 installed. In 1839 it was a Canadian, Samuel Cunard, 

 who secured — in association with two British shipowners, 

 Burns and Mclver — the contract for a monthly Trans- 

 atlantic service from Liverpool to Halifax and Boston. 

 The four steamers built were wood-hulled, driven by 

 paddle-wheels, had good sail-power, and were of the 

 following dimensions : — 207 feet long, 34.I feet broad, 

 1 150 tons burden, and about eight knots speed. A rapid 

 passage to Boston then occupied about fourteen days. 



Another Canadian enterprise, the Allan Line, started 

 about fifty-six years ago. The first steamer built for the 

 company was appropriately named the Canadian. At the 

 time of her construction she ranked among the most 

 itnportant mercantile steamers in existence, and was quite 

 up to date. Her dimensions were : — length, 278 feet ; 

 breadth, 34 feet; burden, 1S73 tons. She had inverted 

 direct-acting engines, driving a screw propeller, and a full 

 sail equipment. 



The Transatlantic service to New York, as was natural, 

 rapidly surpassed that to Canadian ports, but the latter 

 has been continuously improved, and its development has 

 been marked by many notable events. For example, the 

 Allan Line was amongst the first to use steel instead of 

 iron for hulls, and in their two largest steamers now on 

 service, dating from 1903, they were the first to adopt 

 steam turbines for ocean-going ships, although their lead 

 of the Cunard Company was not long. The Virginiayi 

 and Victorian are 520 feet long, 60 feet broad, of 10,750 

 tons, and their maximum speed is 18 knots. The Canadian 

 Pacific Railway authorities added shipowning to their great 

 land enterprises at an early period in their career by build- 

 ing for the Pacific service in 1891 three important steamers, 

 each 456 feet long, 51 feet broad, of 5950 tons, and 17 

 knots speed. These vessels continue on service, and have 

 done splendid work as a link in the "all red " route. 

 Since this step was taken the Canadian Pacific Rail- 

 way has become possessed of a large fleet of -Atlantic steam- 

 ships, and quite recently has placed on the service from 

 Liverpool to Quebec passenger steamships nearly 550 feet 

 in length, 66 feet in breadth, of 14,200 tons,, with a 

 maximum speed of 20 knots. 



The latest addition to the Canadian service lias been 

 made by the White Star Line in the form of two steamers, 

 the Laurentic and Mcga}itic, of 15,000 tons, 550 feet long, 

 about 67 feet broad, and 17 knots speed. In the Laurentic 

 an interesting experiment has been made — Messrs. Harland 

 and Wolff having introduced a combination of reciprocating 

 engines and a Iow-pres<iure turbine. This system was 

 patented as long ago as 1894 by Mr. Charles Parsons, to 



NO. 2081, VOL. 81] 



whom the invention of the modera steam turbine and its 

 application to marine propulsion are due. Mr. Parsons 

 foresaw that while the turbine system would prove superior 

 to reciprocating engines in ships of high speed and with 

 a high rate ot revolution, there would be a possibility 

 of getting better results by combining reciprocating engines 

 with low-pressure turbines in ships of comparatively slow 

 speed, where a low rate of revolution for the screw-pro- 

 pellers was necessary to efficient propulsion. His main 

 object, as set forth fifteen years ago, was " to increase 

 the power obtainable by the expansion of the steam beyond 

 the limits possible with reciprocating engines," and sub- 

 sequent investigations led Mr. Parsons to the conclusion 

 that it would be possible to secure an economy of 15 to 20 

 per cent, by using the combination system as compared 

 with that obtainable with efficient types of reciprocating 

 engines. Many alternative arrangements have been de- 

 signed for combining reciprocating engines with low- 

 pressure turbines ; that now under trial associates twin- 

 screw reciprocating engines, in which the expansion of the 

 steam is carried down to a pressure of 9 to 10 lb. per 

 square inch when working at ma.ximum power, and then 

 completed to the condenser pressure in a turbine. Triple 

 screws are emplo}'ed, the central screw — driven by the 

 turbine — running at a higher rate of revolution than the 

 side screws, which are driven by the reciprocating engines. 

 The Laurentic has been but a short time on service, and 

 few particulars are available of her performances as com- 

 pared with those of her sister ship, fitted with recipro- 

 cating engines. It has, however, been reported that the 

 results have proved so satisfactory that the combination 

 system will probably be adopted in the two large White 

 Star steamers of 45,000 tons now building at Belfast. This 

 favourable view is fully confirmed by the performances of 

 the Otaki, built by Messrs. Denny, of Dumbarton, for the 

 New Zealand Shipping Company, and completed last year. 

 That firm, as is well known, have taken a leading part in 

 the application of the Parsons type of steam turbine to the 

 propulsion of mercantile and passenger steamers, and they 

 possess exceptional experience as well as special facilities 

 for the analysis of the results of trials of steamships, 

 having been the first private firm to establish an experi- 

 mental tank for testing models of ships and propellers on 

 the model of that designed by Mr. W. Froude and adopted 

 by the Admiralty. Messrs. Denny have generously placed 

 at the disposal of their fellow-shipbuilders the principal 

 results obtained on the official trials and earliest voyages 

 of the' Otaki, and have compared them with similar results 

 obtained in sister ships fitted with reciprocating engines.' 

 The Otaki is the first completed ship fitted with the com- 

 bination system and subjected to trial on service, and as 

 the successful application of that system to cargo steamers 

 and steamers of the intermediate type would result in a 

 considerable economy in the cost of over-sea transport, it 

 may be of interest to give some details of her recorded 

 performance. She is 465 feet long, about 60 feet broad, 

 and of 7420 tons (gross). Her dead-weight capability is 

 about 9900 tons on a draught of 27 feet 6 inches, and the 

 corresponding displacement (total weight) is 16,500 tons. 

 The vessel was designed for a continuous sea-speed of 

 12 knots when fulh laden, and the contract provided for 

 a trial speed of 14 knots with 5000 tons of dead-weight 

 on board. The trials were accordingly made at a displace- 

 ment of about 11,700 tons. Her installation of boilers is 

 identical with that of her sister ship, the reciprocating- 

 engined twin-screw steamer Orari, which is 4 feet 6 inches 

 shorter than the Otaki, but generally of the same form. 

 On the measured mile the- Otaki obtained a speed of 

 15 knots, while the Orari reached 14-6 knots. In order 

 to drive the Orari at 15 knots about 12 per cent, more 

 horse-power would have been required, and this is a prac-' 

 tical measure of the superiority of the combination system 

 over the reciprocating twin-screw arrangement in the 

 Orari. The total water consumption per hour of the 

 Otaki at 15 knots was 6 per cent, less than that of the 

 Orari at 146 knots. If the Otaki also ran at 146 knots, 

 the water consumption would have been 17 per cent. less 

 than that of the Orari at the same speed. On the voyage 

 from Liverpool to New Zealand the Otaki averaged about 



1 See a paper by Knei'-eer Commander Wisnom. R.N., in the Prcc^edings 

 of the Institution ofEngineeis and Shipbiilders in Scotland for iqog. 



