574 THE PROGRESS IN STEAM NAVIGATION. 



conditions; it was a verital)l(' triunipli to attain speu'ds of 15 to 16 knots 

 in vessels only itK> feet long, less than 25 feet broad, and under 350 

 tons in displacement. To raise the trial speed to 21 or 22 knots in 

 later vessels, whose design includes the improvements of a quarter of 

 a century, it has been found necessary to adopt lengths exceeding 820 

 feet, and breadths of about 35 feet, with engines developing 4,500 to 

 6,000 indicated horsepower, and with very great increase in coal con- 

 sumption and cost. 



Another interesting contrast is to l)e found in the comparison of the 

 steamers running between Holyhead and Kingstown in 1860 and at 

 the present time. The Dinxft-r of 1860 was 328 feet long, 35 feet 

 ]>road. and rather less than 13 feet draft. Her trial displacement 

 was under 2,000 tons, and with 4,750 horsepower she made 17f 

 knots. She had a steam pressure of 25 pounds per square inch, and 

 was })r()})('lled by paddle wheels driven by slow-moving engines of 

 long stioke. ller successor of 181H) is about 30 feet greater length, 

 Qh feet gri'ater breadth, and about 1(> per cent greater displace- 

 ment. The st(>am ])ressui'e is 160 pounds per sipiare inch. Forced 

 draft is used in the stoke hold. Twin screws are adoptinl, driven 

 by (juick-rumiing Ncrtical engines of the tri])le-expansion tyj)e. Very 

 great economy of coal consumption is thus secured, as compartnl with 

 the earlier \'essel. and nuich lighter propelling apparatus in pro])()r- 

 tion to the ])ower, wliich is from S.OOO horsepower to i),000 horse- 

 power at the full speed of 23 knots. The hull is built of steel, and 

 is proportionately lighter. 



This is a typical case, and illustrates the effect of improvements in 

 shipbuilding and engineering in thirty-live years. The later ship 

 probably requires to carry no greater load of coal than, if so great as, 

 her predec«>ssor. although her engine power is neai'ly dou])le. The 

 weight devoted to propelling machinery' and boilers is probabl}' not so 

 great. Thanks to the use of steel instead of iron and to improved 

 structural arrangennMits. the weight of hull is reduced in comparison 

 with dimensions, and a longer ship is pi'oduced, better adapted to the 

 higher speed. Messrs. Laird, of Birkenhead, who built three of the 

 Le'instt-r class forty years ago and have built all the new vessels, are 

 to be congratulated on their. complete success. Between such vessels 

 designed for short runs at high speed, and requiring, therefore, to 

 carrj' little coal, while the load carried, exclusive of coal, is trifling, 

 and an ocean-going steamer of the same average speed designed to 

 make passages of 3,000 miles, there can obviously be little in common. 

 But equal technical skill is i-equired to secure the efficient performance 

 of both services. In the cross-channel vessel, running from port to 

 port and under constant observation, conditions of working in engine 

 and boiler rooms, as well as relative lightness in scantlings of hull, can 

 be accepted which would be impossible of application in the seagoing 



