126 COALING WARSHIPS FROM COLLIERS IN HARBOR. 



on deck in a very contracted space are four specially designed winches, 

 each provided with two independent metallic friction drums. The winches 

 have double 8 j -inch by lo-inch cylinders. One man controls each winch, 

 having two friction thrust pump handle levers in his hands and steam under 

 foot. Stretched between the spars and high above the deck is a stay of large 

 dimensions. This stay supports a double block over the center of each 

 hatch. The hoisting rope leading from one drum of one winch leads aloft 

 and over one of the pulleys of these double blocks and then drops verti- 

 cally into the hold. 



When the Marine Transfer is set up, two booms are outstretched and 

 fixed by vangs on opposite sides of the ship and so disposed that a line 

 drawn from their ends passes directly over the center of the hatch. To 

 the ends of these booms pulley blocks are attached. To handle bags of 

 coal three lines are used and two winches. One line is used to hoist the 

 bags vertically from the hold. The other two lines lead in opposite direc- 

 tions to pulleys at the ends of the outstretched booms and back to a swing- 

 ing block surrounding the hoisting rope. These two lines swing the load 

 to and from the ship alongside. The hoisting line swings pendulum-like 

 from the pulley block supported high above the center of the hatch. This 

 line leads through a floating trolley or swinging block provided with large 

 pulleys. This swinging block is hauled both ways by lines known as the 

 inhaul and the outhaul. These lines are operated by the two drums of 

 the winch known as the swinging winch. The weight of the swinging 

 block is counterbalanced by adding a line (pendulum rope) to the swinging 

 block and leading it aloft to the double block, thence to a pulley near the 

 mast and downward to a weight suspended on its end. This weight runs 

 on a standing rope as a guide (Plate 35). 



OPERATING A SELP-FILLING BUCKET. 



In operating a self -filling or clamshell bucket a fourth line is added 

 parallel to the hoisting line and operated by the second drum of the hoisting 

 winch. This line is employed in closing the bucket. The operation is as 

 follows : — 



Suppose the bucket to be open on the coal in the hold. 



1. By hauling in with one drum the bucket is closed, grabbing a load 

 of coal. 



2. By winding in both bucket lines the bucket is hoisted. 



3. When the bucket is clear of the hatch it is swung outboard by 

 hauling in on the outhaul rope and paying out (at the same speed) the 

 inhaul rope. 



