EXPLANATION OF THE PLATES. 473 



D, The new line of post, with the rake taken out and brought perpendicular to the 

 new line of keel, B. 



E. The stem to have a flare or flam to correspond with the bow. 



To prevent rolling as much as possible and falling to leeward, two deep bilge 

 keels to be fastened to the bottom plank, with bolts clinched on the inside. (These 

 keels have been well tested in certain vessels belonging to the Honourable East India 

 Company, in Bengal.) 



The fore and after bodies of the American schooners (applied as just described) 

 have been proved to be the best suited for velocity, the sharp flaming bow dividing 

 the fluid with the greatest facility, and the fineness of the run allowing it to pass to 

 the stern with the utmost rapidity. 



This improved form is obtained by giving a great proportion of length to breadth, 

 which has been so successfully adopted in the construction of all recently con- 

 structed steamers (particularly those built by private companies or individuals). 

 It is recorded in the translation of Chapman's celebrated work by Dr. Inman : 

 " Care must be taken to shape the fore and after bodies, the former so that the 

 fluid may be cloven with facility, and at the same time the displaced fluid dis- 

 persed and transmitted towards the stern with as much ease as possible." Velocity 

 in steam vessels is, therefore, obtained by a light draught of water, and keeping the 

 fore and after bodies sharp, and giving the least proportion of length to breadth with 

 reference to the required stability, viz. for sea-going steamers, six times the breadth 

 for the length at the load water line ; in vessels for inland or river navigation, the 

 length has been carried to ten times the breadth in some of the American boats. Vide 

 Stephenson's late work on American Engineering. 



PLATE XCVII. 



DRAUGHT OF THE FORBES STEAMER, CONSTRUCTED AT CALCUTTA, 

 BY ALEXANDER HENDERSON, ESQ.; CHINESE RIGGED. 



This plate presents a sketch of the masts and sails of the steamer Forbes, as fitted 

 when she towed a ship of 380 tons from Bengal to China against the monsoon in 1830, 

 with the fore-sail and main-sail; the plan of the Chinese sail was adopted as best suited to 

 the purposes of a steamer, giving the greatest spread of canvas, with the least weight 

 of mast and rigging ; the stretchers or yards in the body of the sail, by dividing the 

 strain on the mast, are useful to reduce the weight aloft and require little rigging ; 



3 o 



