240 On Low Steam Power to Vessels, instead of Sails. [Oct. 



with a 30 horse engine would run at least 7 knots an hour, or 2^ above 

 her average, and one knot more than she would go under the most 

 favourable circumstances without sails. Supposing then that such vessels 

 used light sails occasionally, such as when running with a trade or 

 monsoon on or abaft her beam, the calculation for her would be as 

 follows ; 



STEAMER OF 380 TONS WITH 30 HORSE ENGINE. 



£ 



Expesces as before 2050 



Renewing and repairing sails per annum ,. CO 



2110 



Coal for steaming 15,800 miles at 120 miles per day, 132 



days at 8 lbs. per horse power per hour, 310 tons at 16 S.. 270 



Total expence of steaming 15,800 miles 2380 



Do. do. 13,800 miles 2080 



Do. do. of sailing do 2150 



Difference in favour of steaming 70 £ 



The speed of such a vessel would be 3 knots against a head sea and 

 wind, 5 knots in smooth water and calm weather, and 7 using her sails 

 with a trade of average strength; her average could not be less than 5 

 knots, while the sailing vessel averages only 3| knots ; or the steamer 

 would perform her voyages in three-fourths of the time of the sailing 

 vessel. The sailing vessel was 303 days at sea out of 23 months, run- 

 ning a distance of 26,500 miles ; the steamer would in this case accom- 

 plish that distance in 220 days, and consequently allowing the same time 

 in port for both vessels, she would perform the same work in a little 

 more than 20 months, or at the rate of 15,800 miles per annum ; for 

 this, allowance has been made in the above calculation. 



Hence it appears that a vessel of 389 tons, worked by an engine of 

 30 horse power, fitted with movable masts and 3 lug sails to be used 

 when there is a steady leading wind, would be worked cheaper at an 

 average speed of 5 knots than a sailing vessel at 3f knots ; that is, she 

 would at less expence perform her voyages in | of the time of a sailing 

 vessel. 



Or if such a vessel with a leading wind, made use of wind only, she 



