160 CARGO TRANSFERENCE AT STEAMSHIP TERMINALS. 
are used, both fixed and traveling. The half-arch crane as illustrated 
is preferred at Antwerp to serve the open space between the shed and the 
vessel. Liverpool on the other hand has 170 roof cranes in one section. 
These gantry cranes have a hoisting capacity of one and one-half to three tons 
and the motors are generally of 250 or 500 volts. With a 6,o00-pound 
load, the cost of electric current is given as 0.63 of a cent per ton, with a 
_1,000-pound load 1.2 cents per ton. ‘This is at the rate of 8 cents per kilo- 
watt-hour, more than double the rate in New York. 
The speed of hoisting three tons is two feet per second, or four feet per 
second with half aton. In one case the average load at the station was 335 
kilowatts per crane when 20 cranes were at work and 2} kilowatts when 
70 cranes were in operation. 
The performance of cranes is given in cycles. The cycle often men- 
tioned consists in attaching and hoisting the load 50 feet, swinging 150 feet, 
lowering to the platform, releasing the hook, raising, swinging back and 
lowering the hook to the starting point. 
Twenty cycles per hour can easily be accomplished although claims are 
made for 40 or more. ‘There are most complete records of the me 
of these cranes at Hamburg. 
The ship’s winch is in most cases, all conditions contidereel as rapid and 
economical as these gantry cranes. The winch, however, can only place the 
freight upon the edge of the pier while the gantry crane can serve a half 
circle upon the pier some 45 feet in radius, loading and unloading cars and 
serving the space within this area. 
The cost per ton of thus swinging the freight upon the pier, either by 
winch or gantry, is from two to five cents per ton; but the after-cost by 
manual labor for distribution and tiering is over 30 cents per ton additional. 
Manual Labor Costs —The following detailed figures will make clear the 
cost of handling by manual labor. 
Loading 2,000 Tons in 17 Hours. 
INumberof menremployed arenes eee er 150 
Meringe anen(extra)eanmueens oars See es eee 20 
Men in vessel included in the above................ 60 
Numberof truckerss.te.. Sucre teuden min ebeian creer 90 
shonnageyoroft-shore liehterse eee eee eee 1,000 
MTonmageracross piers: ine bes saan an) a ewe eee ee 200 
‘Tonnageifromidrays soy. Gace anes oct eee eee - 800 
Hand truck loads............. sy Satcp lls es gH aM Ae 10,955 
