THE PROGRESS IN STEAM NAVIGATION. 578 



cargo. The enterprise and skill of shipowners have proved eciuul to 

 this new departure, as the}^ have in all other developments of steam- 

 ships. How much further progress will be made in the sizes and 

 speeds of these mixed cargo and passenger steamers can not be fore- 

 seen. The limits will be lixed by commercial considei-ations and not 

 by the capability of the ship})uilder. In passing, it may be noted 

 that while the lengths and In-eadths of steamships have been gn^atly 

 increased, there has been but a moderate increase in draft. Di-aft 

 of water is, of course, practically determined by the depths :ivailal)le 

 in the ports and docks frequented, or in the Suez Canal for ^•essels 

 trading to the East. From the naval architect's point of view, increase 

 in draft is most desirable as favoring incn^ase of carrying powci- and 

 economy of propulsion. This fact has been strongly represented by 

 shipowners and ship designers, and not without result. The respon- 

 sible authorities of many of the principal ports and of the Suez Canal 

 have taken action toward giving greater depth. Other changes have 

 become necessary on the part of dock and port authorities in con- 

 sequence of the progress made in shipi)uilding. Docks and dock 

 entrances have had to be increased in size, more powerful lifting 

 appliances provided, and large expenditure incurred. There is no 

 escape from these changes if the trade of a port is to be maintained. 

 The chief lesson to be learned from past experience is that when works 

 of this character are planned, it is wise to provide a large margin 

 bej^ond the requirements of existing ships. 



CROSS-CHANNEL STEAMERS. 



The conditions to ))e fuliilkHl in vessels designed to steam at high 

 speed for limited periods obviously differ essentially from those hold- 

 ing good in ocean-going steamers. None the less interest attaches, 

 however, to cross-channel steamers, and in no class has more notable 

 progress been made. So far as I am informed, the lirst steamer i)laced 

 on the route between Dover and the Continent in 1821 was of ;♦«( tons 

 burden, 30-horsepower nominal, and maintained a speed of 7 to S 

 knots. She was built by Denny, of Duml)arton, engined hy Robert 

 Napier, and named the Ro7, Roy. It is interesting to note that the 

 lineal successors of the builder of this pioneer vessel have produced 

 some of the most recent and swiftest additions to the cross-cha.mel 

 service. In 1861-H2 a notable advance was made l)y the buikling of 

 vessels which were then remarkable for structure and speed, although 

 small and slow when compared with vessels now running. Th.Mr 

 designers realized that lightness of hull was of supreme unportaruv, 

 and with oivat trouble and expense ol)tained steel of suitable (luabty. 

 The machtnery was of special design and relatively light for the power 

 developed. A small weight of coal and cargo had to be earned, and 

 the draft of water was kept to about 7 feet. Und.-r then cx.stu.g 



