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304 and cranes. Transference between the pier shed and the quay shed and warehouse is by the overhead fixed and movable tracks and small motor trucks. Freight Handling Equipment It can be asserted that combina- tions of the traveling gantry jib cranes, the ship’s winch, the overhead traveling hoists in trains, and the movable tracks and the electric motor truck fulfill all the exacting condi- tions of the transferring and handling of miscellaneous cargoes or package - freight. Great flexibility and large range of operations are attained, eli- minating delays and congestions, and reducing the employment of unskilled manual labor to the minimum, with a continual successsion of movement of the freight. There is a great variation in the cost and speed of cargo transference and handling, due to different kinds ot THE MARINE REVIEW tracks, elevated 17 to 25 feet above the rails, with a jib length of. 50 feet and a radius of°35 to 50°feet. It ts capable of lifting two tons at a speed of 3 to 4 feet per second; or 3 tons, or even more, at a proportionately less speed. The slewing is from 7 to. 10 feet per second, or 2% swings per minute. The traveling speed is about 70 feet per minute. There is a slow speed motor for each movement, pre- ferably, a direct current motor. The characteristics of these cranes are the quick movements of lifting, rotating, lowering, starting, and positive brak- ing. The controlling cab is placed within the jib members, so that the operator may obtain an unobstructed view of the complete hoisting opera- tions. Traveling hoist trains consist of one tractor, or the conveying mechanism, drawing three or four electric hoists. All are controlled by one _ transfer- man. .The speed of the train is 750 important and common types as follows: horsepower motors. horsepower motors. September, 1916 Portable electric dock winches, with 20- Stationary, electric. dock witches with 18- Floating steam hoisters. “Floating grain elevators. * Whip hoists. Traveling unloaders, 5 to 10 tons capacity. Elevated stationary hoisting winches. Pillar cranes. Locomotive cranes. Stationary bridge cranes. Lifting towers and belt conveyors. Derrick booms and grab buckets. Coal dumps on tipples. Barrel conveyors and elevators. Gravity chutes and conveyors. Bag and box chutes. * Paggage escalators. Cargo chutes. Blind hatch hoists. Stationary cranes, of great hammer type, capacity. — As an example of one of the latest and best coal-handling plants of large capacity, reference is made to the installation at Panama for the United States government. UNLOADING PLANT OF A FLORIDA LUMBER COMPANY cargoes and favorable or unfavorable conditions; but with a correctly de- signed terminal, using the mechanical appliances as described, manual labor costs and the time of loading and discharging can be reduced by one- half. In the place of the gantry jib crane, the transporter or the canti- lever gantry crane can be substituted, in some cases, to great advantage; but on account of the single or double gantry jib crane being able to serve ‘some 100 feet of lineal water frontaye without any traveling movement, and the facility with which, combined with the overhead traveling hoists, burton- ing can be effected, preference is gen- erally given to this type. -The following are a few of the general specifications for gantry jib cranes, The half-arch or semi-portal crane has: "a horizontal limb of from 35 to 50 feet spanning two or three feet per minute with 6 to 8-ton load. Each of the hoists has a lifting capacity of 2 tons at.60 to 80 feet per minute, or 3 tons at less speed. Two traveling hoists combined can give a lifting capacity of 4 to 6 tons. The connection between the movable cross or loop track and the fixed track is by means of gliding bridges. The number of traveling hoists is proportioned to the number and ca- pacity of the gantry cranes, so that in burtoning from the hooks of the gantry cranes to the hooks of these traveling hoists there is no: delay or congestion, either of the cranes or hoists. Types of Hoists are Many Many types of hoisting .and con- veying appliances are installed at ma- rine terminals, but these’as a rule are designed for special commodities and not for universal application. It is possible only to enumerate the: more OVERHEAD TRAVELING HOISTS HANDLING SUGAR BETWEEN SHIP, SHED AND WAREHOUSE In loading iron ore into ships, the ore is brought from the mines in cars, each holding about 50 tons, and is dumped through bottom doors into the ore dock pockets, taking often only 15 seconds per car. From the pockets, the ore runs by gravity through many hatches into the hold. A vessel can be loaded with 12,000 tons of ore in one hour. For unload- ing cars of coal into the ships, the most efficient method consists in rais- ing the car filled with coal and, by inversion, dumping it into the vessel. Such car dumps have a capacity of 900 tons per hour. For transferring sand, gravel and a smaller coal ton- nage, jib cranes of various types and bridge transporters © * are installed. These have. a: capacity of. 60. to 100 tons’ per hour. For the handling of phosphate rod | moving belts to the ship’s side are (Concluded..on: page 318)... 2 3 3 4 . ee 3