1840.] On Low Steam Power to Vessels^ instead of Sails, 241 



would on an average of voyages save about ^ of her fuel, and hence she 

 could run 6,000 miles with the same fuel, as she would require for 4,000 

 miles if she made no use of her sails, and as her speed in that case 

 would be 3 against wind and sea, 5 in calms, and 5 1- on an average, using 

 her sails only ; her total average would be about 4| miles or one-fourth 

 more than that of a sailing vessel. That is 



A vessel of 380 tons, with a 30 horse engine and fitted with moveable 

 masts and light sails to be used in leading winds, without steaming at 

 such times, cou^d be worked as cheaply as a sailing vessel, in voyages 

 of from 1,000 to 7,000 miles without taking in coals, at a speed | greater, 

 or she would in her voyages save one day in 4. 



The effect of occasional use of sails in such a vessel, with a 50 horse 

 engine, may next be examined. 



Steamer of 380 tons with engine op 50 horse povs^er, using light 



sails occasionally. 



£ 



Expences as before, omitting coals ^, 2376 



Renewing sails, per annum .. 60 



^ 2438 



Coal for 16,800 miles at 150 miles per day at 8 lbs. per horse 



power per hour, 480 tons at IGs 384 



Total expense of steaming 16,800 miles 2820 



Do. of do. 13,800 2320 



Do. of sailing do , 2150 



Excess of expense of steaming , l7o 



or tV 



The speed of this vessel would be 4 knots against a head wind and 



sea, 6 knots in smooth water and 7^ using her sails also ; taking her 

 average at 6^^ knots, she would perform her voyages in f of the time of 

 the sailing vessel. She would have performed the distance run by the 

 latter, viz. 26,500 miles in 177 days, instead of 303, saving 4 miinths 

 out of 23, the whole time occupied by the sailing vessel, and running in 

 the year 16,800 miles. Allowing the steamer to lose as before calculated 

 y\ of her freight, the proportional expence for the same amount of tonnage 

 would be 



