700 ANNUAL REPOBT SMITHSONIAN INSTITUTION, 1913. 



The coal rate has fallen from 1.6 pounds per horsepower per hour to 

 1.3 pounds, while for a 3,000-mile voyage the dead weight carried 

 per ton of coal has increased from 23.5 tons to 26.4 tons. 



Rapid loading and discharge of cargo are of vital importance to 

 the tramp vessel, and it is evident that the less the cargo has to be 

 moved horizontally along holds and 'tween decks before coming 

 under the hatchways to be lifted, the more rapidly can it be handled. 

 Hatches have therefore increased greatly in size, and in some vessels 

 are now almost continuous, and in breadth nearly equal to half the 

 vessel's beam. With the same object of facilitating the passage of 

 cargo to and from the hatchways, hold pillars have almost disap- 

 peared, and in place of the double row of slender pillars at intervals 

 of about 4 feet, we find large open holds and decks supported by con- 

 tinuous longitudinal girders under the beams and four large plate- 

 and- angle pillars only. 



The steam winch still remains the best means of handling cargo, 

 being more robust and less complicated than either electric or 

 hydraulic plants. The winches themselves have been greatly im- 

 proved, and instead of a single 6-inch by 10-inch winch at each hatch 

 and chain falls we find a pair of 8-inch by 12-inch machines with 

 helical gearing and wire-rope pendants. The normal derrick is now 

 of steel tube for a 6-ton lift in place of the old 3-ton wood derrick, 

 while a special steel derrick at each end of the vessel can handle a 

 load of 30 tons. At the same time the size of the drums has in- 

 creased from 12 inches to 24 inches and the working pressure from 

 50 to 100 pounds. Larger wearing surfaces have been provided and 

 locomotive-type valves fitted, so that the cargo winch of to-day is 

 not only more powerful and more rapid than its predecessor, but has 

 also greater immunity from breakdown. 



Crews' accommodation has been greatly improved. Comfortable 

 mess rooms are now provided separately from sleeping quarters; 

 galvanized-iron berths have replaced wooden bunks; steam heating 

 and stoves are provided ; each man has a locker fitted with drawers 

 for his clothes, and his chest goes to a separate storeroom ; there are 

 plunge and shower baths for seamen and for firemen as well as for 

 the captain, officers, and engineers, and a well-equipped hospital is 

 provided. 



The triple-expansion engine still holds its place in the engine room 

 of the cargo tramp. The fourth cylinder of a quadruple engine 

 would mean additional complication and one or two additional engi- 

 neers. Three main boilers of equal size are used, two under forced 

 draft for propulsive purposes, the third under natural draft for 

 dealing with cargo and to assist the others in cases of emergency 

 when a little extra speed is called for. 



