THE PROGRESS IN STEAM NAVIGATION. 



Rv Sir William H. White, 



Asmrmit. ControUer and Director of Naval Construction of the Britvih Navy. 



Steamship design, to be successful, must always be based on experi- 

 ment and experience as well as on scientific principles and processes. 

 It invoh'es problems of endless variety and great complexity. The 

 services to be performed by steamships differ in character, and 

 demand the production of many distinct types of ships and propelling 

 apparatus. In all these types, however, there is one common require- 

 ment — the attainment of a specified speed. And in all types there 

 has been a continuous demand for higher speed. 



Stated l)roadly, the task set before the naval architect in the design 

 of any steamship is to fulfill certain conditions of speed iii a ship, 

 which shall not merely carry fuel sufficient to traverse a specified 

 distance at that speed, but which shall carry a specified load on a 

 limited draft of water. Speed, load, power, and fuel supply are all 

 related, and the last two have to be determined in each case. In some 

 instances other limiting conditions are imposed afl'ecting length, 

 breadth, or depth. In all cases there are three separate efficiencies to 

 be considered — those of the ship, as influenced by her form; of the 

 propelling apparatus, including tht^ generation of steam in the boilers 

 and its utilization in the engines, and of the propellers. Besides these 

 considerations the designer has to take account of the materials and 

 structural arrangements which will best secure the associtition of 

 lightness with strength in the hull of the vessel. He must select 

 those types of engines and boilers l)est adapted for the service pro- 

 posed. Here the choice must be influenced by the length of the 

 voyage, as well as the exposure it may involve to storm and stress. 



Obviously the conditions to be fulfilled in an ocean-going passenger 

 steamer of the highest speed, and in a cross-channel steamer designed 

 to make short runs at high speed in comparatively sheltered waters, 

 must be radically diflerent. And so must be the conditions in a swift 

 seagoing cruiser of large size and great coal endurance, from those 



^Presidential address before the mechanical section of the British Association for 

 the Advancement of Science, 1899. Printed in CasHicr's Magazine, November, 1899. 



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