1868.] 



and Weight of Iron-clad Ships. 



309 



to build another ship, which shall also steam 14 knots, carry the same 

 proportionate supply of coal to engine-power and proportionate quantities 

 of stores, but shall have her armour and backing of double the weight of 

 armour and backing of the 'Bellerophon' and ' Minotaur,' then (1) what 

 will be the size, engine-power, and cost of the new ship of the ' Minotaur' 

 type, and having the same mean draught and depth of armour? and (2) 

 what will be the size, engine-power, &o., if built on the * Bellerophon ' 

 type, and having her mean draught and depth of armour? — this condition 

 implying, of course, that the same constants of performance as before 

 will be realized in each case. On account of the great disproportion in 

 size between the two types of ship, it is obvious that the smaller one will 

 require much less weight of equipment. It is assumed, therefore, that the 

 additional weights of the smaller ship (exclusive of engines, boilers, and 

 coals) amount to 700 tons, and those of the larger ship to 1 000 tons. The 

 developed power of the engines, proportionate supply of coal, and the 

 weight of engines &c. are taken exactly the same as in the hypothetical 

 case first given. 



By proceeding with the investigation for each case in a way similar to 

 that sketched for the hypothetical ships, only treating the breadth extreme 

 of the mean horizontal sections of the new ships as the unknown, the fol- 

 lowing results are obtained. The new ship of the ' Minotaur' type wliich 

 fulfils the required conditions will be nearly 490 feet long, 72| feet breadth 

 extreme, and have a total displacement of 14,253 tons ; while the new ship 

 of the * Bellerophon' type will be 380 feet long, 71 feet breadth extreme, 

 and have a total displacement of 10,950 tons. It thus becomes obvious 

 that a correction is needed in the weight per square foot of hull in the 

 new ship of the * Minotaur ' type, as her length has been so greatly in- 

 creased : it is considered that an increase of at least 10 per cent, is re- 

 quired ; and this is the allowance made. On the other hand, the new ship 

 of the * Bellerophon' type is still shorter than the 'Minotaur' herself, and 

 the displacement is not much greater than the actual displacement of the 



* Minotaur ;' so that no correction is needed in her weight per square foot 

 of hull. When the correction has been made for the new ship of the 



* Minotaur ' type, the final results in round numbers are as follows for the 

 two classes of ship : — 



Length 



Breadth 



Tonnage 



Nominal horse-power 



Indicated ,, 



Weight of hull 



,, armour and backing 

 „ engines and coals . . 

 stores carried ...... 



Displacement 



New ship of 

 Minotaur' type. 



New ship of 

 Bellerophon' type, 



510 feet. 



380 feet. 



75 „ 



71 „ 



13770 tons. 



8620 tons. 



1080 H.P. 



1080 H.P. 



7560 „ 



7560 „ 



7100 tons. 



4460 tons. 



5190 „ 



3630 „ 



2160 „ 



2160 „ 



1000 „ 



700 „ 



15450 „ 



10950 „ 



VOL, XYI. 



2 r 



