172 REFUELING WARSHIPS AT SEA. 



BAGGING AND TRANSPORTING COAL ON COLLIER. 



Colliers of the Jason and Cyclops type, equipped with coaling-at-sea apparatus, 

 should use their own clamshell buckets for digging coal in the hold and delivering 

 it to a hopper located on deck. Coal from the hopper should be fed to coal bags 

 on trucks. In this way one man will fill as many bags as nine men in the hold. 



These trucks should run on tracks attached to the deck. An inclined portable 

 section of track should be provided between the poop deck and the main deck for 

 passing trucks from one deck to another. A winch and rope leading around the 

 bags resting on the truck will safely transport the loaded truck up the incline. The 

 truck may then be pushed by hand until it reaches the quarter-deck. 



Here the track should make a circle around to the opposite side of the collier 

 with two short side tracks, one on each side of the collier. Thus three trucks, each 

 with two 800-pound bags, may be assembled abreast, when the six bags can be taken 

 by the cableway carriage. At this point chocks will be necessary to hold the trucks 

 until their load has been taken. The flanges of the wheels will keep the trucks in 

 line, moving forward and aft, but the instant they reach a point directly at the 

 loading station they will have to be controlled as against the rolling of the collier. 



AUTOMATIC TENSION ENGINE VERSUS TOWING ENGINE AND SEA ANCHOR. 



The author's first drawing of a cableway for coaling ships at sea, dated Octo- 

 ber 30, 1893, showed a "Compensating Tow-line Engine." None of the manufac- 

 turers of "towing engines" would undertake to build an engine or winch that would 

 perform the functions required. 



In a "towing engine" a considerable slackening of the tow-line causes the tow- 

 ing engine to operate its winding drum and thus coil in the slackened tow-line. The 

 revolutions of the drum are geared to a steam valve and the pressure of the steam is 

 thereby reduced. Subsequently an overstrain in the tow-line pulls the engine back- 

 ward because it carried a low steam pressure. Again, the drum in unwinding 

 through its connecting gear raises the steam pressure, thus leaving the towing en- 

 gine in a position to act again to wind in the slackened cable. Towing engines are 

 heavily compound geared. They are very slow in taking up the slack. 



In the automatic tension engine, which had to be created for this special pur- 

 pose, the instant the main cable slackens the steam pressure is immediately raised 

 and the engine responds to restore the tension by winding in the main cable. Con- 

 versely, the instant the tension in the main cable is increased the steam pressure is 

 immediately lowered and the engine yields and pays out as required. The automatic 

 tension engine is capable of taking in slack even faster than it is given by the mo- 

 tion of a collier and a battleship operating in a heavy seaway. The automatic ten- 

 sion engine keeps practically a uniform tension in the line, while the towing engine 

 makes no pretence of doing so. 



The sea anchor, which formed an important part of all the earlier installations 



