ECONOMICAL CARGO SHIPS. 91 



tical for each length of vessel irrespective of speed. The engine-room weights are 

 taken as varying directly with the horse-power, taking 4 horse-power to each ton 

 of engine-room machinery. The total deadweight was assumed to be the difference 

 between displacement and the sum of steel hull, outfit, and engine-room weights. 



(d) Cost of Ships. — The cost of the steel hull was assumed to vary directly 

 with the weight of steel used, and the cost of outfit was taken as constant for 

 each size of ship. The cost of propelling machinery is based directly upon the 

 horse-power developed ; and the basis of these costs was so chosen that the 400-foot 

 ship, at II knots speed, would show a cost of approximately $150.00 per deadweight 

 ton. 



(e) Weight of Fuel and Stores. — The fuel oil consumed was figured at one 

 pound per indicated horse-power per hour, plus a fixed amount for each size of vessel 

 in port. The port fuel consumption allowed for minimum detention was taken as 

 20 tons for the 350-foot ship, 30 tons for the 400-foot ship, 40 tons for the 450-foot 

 ship and 50 tons for the 500- foot ship. A figure was taken for fresh water, make- 

 up feed, and consumable stores equal to one-half the weight of the fuel oil required 

 per voyage. 



In fixing a fuel rate per ton of oil fuel it is intended that this figure should 

 cover also the cost of lubricating oil, fresh water and similar charges based on 

 the horse-power of the engine. For this reason $6.00 and $12.00 as fuel rates 

 would represent a cost somewhat lower than this for the oil alone. 



(/) Port Detention. — The time in port is of great importance in the esti- 

 mated cost of operation of a ship. This is a variable figure, and calculations are 

 given showing the effect with minimum detention and with a detention equal to 

 twice the minimum. I have taken a figure for the minimum length of time in which 

 a vessel should be detained in port as depending on the quantity of cargo which 

 must pass through every square foot of hatch. This quantity, of course, with simi- 

 larly designed ships depends directly upon the depth of the ship, and I have there- 

 fore allowed one day in port for every 5 feet in depth of ship, as a minimum port 

 detention figure. In addition to the above port detention, thirty days per annum 

 have been allowed for overhaul. 



(g) Operating Expenses. — The cost of crew is estimated from the United 

 States Shipping Board's rate current at the beginning of this year and includes an 

 allowance of $300.00 per annum per man for sustenance. In addition, a manage- 

 ment allowance has been made of $500.00 per month. The cost of manning, how- 

 ever, must be considered as only approximate, as the exact number of crew would 

 depend to a certain extent on design of ship and route. 



Depreciation, insurance and up-keep have been figured at 13 per cent per an- 

 num on the first cost of the vessel. Tonnage dues have been assumed at $1.50 per 

 net ton register, and the assumption has been made, for the sake of comparison, 

 that the net tonnage in each ship would be equal to one-third of the load displace- 

 ment in tons. 



After figuring out the cost of the ship, its deadweight carrying capacity in tons 



