TABLES OF STEAM NAVY. 



of the piston. The pressure multiplied by the velocity gives the 

 effective force of the piston, or, what is the same, of the engine 

 exerted through a given number of feet per minute ; and since the 

 force called a horse-power means 33000 Ibs. acting thus one foot 

 per minute, it follows that the nominal power of the engine will 

 be found by dividing the effective force exerted by the piston, 

 multiplied by the number of feet per minute through which it acts, 

 by 33000. 



It is assumed in all Admiralty contracts, and generally also in 

 those of the commercial marine, that, after deducting from the 

 total pressure of steam in the boiler that portion which is 

 neutralised by the gases and uncondensed steam in the condenser, 

 the friction of the moving parts and all other sources of resistance, 

 the actual available or effective pressure of steam upon the piston 

 is at the rate of 7 Ibs. per square inch of piston surface. The 

 total nominal effective action of the piston in pounds will therefore 

 be found by multiplying the number of square inches in the area 

 of the piston by 7. 



93. In the following tables, obtained from the government 

 authorities, will be found a complete statement of the strength of 

 her Majesty's steam navy up to the 1st of April, 1856. 



By Table I. it appears that the number of line-of-battle ships 

 fitted and fitting with the screw-propeller was then 43, carrying 

 a total number of 3797 guns, and propelled by engines of the 

 collective power of 22950 horses. This is at the average rate of 

 88| guns, and 533 horses per vessel ; the proportion of guns to 

 horses being about 6 horses per gun. 



By Table II. it appears that the number of frigates and 

 mortar-ships was 24, carrying collectively 889 guns, and propelled 

 by engines of 10560 horse-power, being at the average rate of 

 37 guns, and 440 horses per vessel ; the proportion of horses to 

 guns being about 12 horses per gun. 



By Table III. it appears that there were 90 war steamers fitted 

 with paddle-wheels, carrying the total number of 500 guns, and 

 propelled by engines having the collective power of 24640 horses, 

 being at the average rate of 5^ guns, and 274 horses per vessel; the 

 proportion of horse-power to guns being about 50 horses per gun. 



By Table IY. it appears that there were 76 smaller vessels fitted 

 with screw-propellers, consisting of corvettes, sloops, and despatch 

 boats, carrying in all 761 guns, and propelled by engines of the 

 collective power of 16202 horses, being at the average rate of 10 

 guns 'and 213 horses per vessel; the proportion of horse-power to 

 guns being therefore about 21 horses per gun. 



In Table Y. is given the number and power of the troop and 

 store-ships, water-tanks, &c. ; in Table YI. a statement of the 



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