DESIGN AND CONSTRUCTION OF PASSENGER STEAMERS. 279 



deck houses would not go well on such vessels; they are one solution of the ventilation 

 question that cannot be ignored, for we all like an airy room. There is no doubt that ven- 

 tilation plays a big hand in the popularity of a ship; in tropical runs it is of the essence. For 

 such vessels all modem advances in the ventilation question will have to be utilized, but 

 tliere is no reason to doubt the ability of the shipbuilder to meet the need, once it is rea- 

 lized how great it is ; American warship practice has proved that. I believe that, during the 

 war, the British paid us the compliment of appointing a committee to study our methods in 

 this respect. 



It will mean a few less rooms and larger ducts, fans in duplicate to avoid breakdown 

 and a margin in boilers and dynamos over the present practice. 



The claims of the watertube boiler over the Scotch for high-speed ships have made good 

 to such an extent that they will feature more largely in future ships. 



THE COST OF HIGH SPEED. 



Apart from the initial cost of the machinery necessary to obtain high speed, the fuel 

 bills become very high. For example, consider a 7S0-foot Atlantic liner of varying speeds 

 from 15 up to 30 knots; such a ship would have a beam of about 90 feet and a deep draught 

 of 36 feet. Call the voyage 3,000 miles, which gives a round figure close enough for our 

 purpose. Remember, too, that as speed goes up cargo carrying ability goes down and 

 passengers, mails and express matter become ultimately the sole sources of revenue, out- 

 side subsidy. The figures are about as follows: 



speed Total Cargo Oil fuel, Cost of fuel, 



at sea {knots). S.H.P. deadweight. deadtueight. one zt-ay {tons). one-way. 



15 16,000 29,000 26,500 1,450 $26,100 



20 38,000 23,000 19,400 2,550 $45,900 



25 73,000 14,000 9,000 3,900 $70,200 



30 113,000 5,800 5,000 $90,000 



Such a vessel would carry some 600 first, 450 second and 1,000' third-class passengers 

 and would be quite big enough for speeds all the way to 30 knots. It is seen that the 30- 

 knot ship carries nothing but passengers, mails, stores and bunkers, which is the logical 

 outcome of this investigation. 



Oil fuel is figured at six cents a gallon or $18 a ton; a figure which, of course, is sub- 

 ject to variation. It would be well to pursue this further, but the above table will show that, 

 with cargo capacity falling from 26,500 tons to nothing and fuel costs rising from $26,100 

 per voyage to $90,000, the economics of the large ship are not easy. It is clear, however, 

 that the greater number of voyages per year for the 30-knot ship must also be taken into ac- 

 count. This may be summarized somewhat as follows : 



