162 A TREATISE ON DREDGES AND DREDGING 



kitchen, washroom and toilet. On the upper deck forward is the 

 operating-room and three cabins for the captain, engineer, and 

 steward. On the upper deck, aft, is a 16X16 ft. bunkhouse for 

 eight men. All the rooms are heated by steam. 



The main hoisting engine is of the double-cylinder, double-drum 

 type, placed on the main deck forward. The bedplate is extended 

 in front and carries the inner bearings of the large spur wheels. 

 These wheels are thus made an integral part of the engine and the 

 maintenance of a proper relation between the pitch lines of the spur 

 wheels and the pinions on the main crankshaft is assured. The engine 

 cylinders are 16X18 in. The drums are all actuated by cork- 

 inserted frictions. These frictions are the standard Lidgerwood type, 

 made of hard wood turned to a truncated cross-section and working 

 against a female surface of turned cast iron. Three-quarter inch 

 holes on 2-in. centers were bored in the faces of the wood and corks 

 pressed into them. The holes are staggered so that the corks cover 

 the whole metal surface of the female section as the friction revolves. 

 It is stated that the cork surface about doubles the holding power 

 of the friction and maintains the grip even if grease gets on the 

 surfaces. It is believed that this is the first time cork inserts were 

 used in dredge work. 



In the hold is the backing drum, operated by a wheel which 

 meshes into one of the large spur wheels of the main drums. The 

 friction of these three drums is set up by steam nips built with 

 wrought-iron toggle levers and actuated by an Osgood patent steam 

 grip cylinder. The form of this grip is novel. The thrust on the 

 main drums and backing drum is transmitted from the thrust collar 

 to the drum through a special roller bearing made by the Philadelphia 

 Roller Bearing Co. These were adopted to reduce the frictional 

 losses incident to the ordinary arrangement and also avoid the 

 cutting of a key way through the main shaft. They have proven 

 very satisfactory. 



A double-cylinder, 10Xl2-in. engine is placed in the hold forward 

 and the fore and aft spuds on both port and starboard sides are 

 operated by it, through friction drums. The spur-wheel shaft 

 extends clear across the hold. Near each end it has a pinion which 

 engages two spur wheels, one on each side of the shaft, each of which 

 is connected with a friction drum. These four drums carry chains 

 leading to the four spuds. At the extreme ends of the main shaft 

 are bevel gears through which power is transmitted to two forward 



