[11] CONSIRUCTION AND WORK OF FISH-HAWK. 13 



wrought-iroii diiving pins fastened by a cross-key in forward wheel and 

 working free on composition bearing-plates in after wheel. The wheels 

 are 3 feet 4 inches diameter, with mortises on periphery for turning the 

 eugine with a pinch-bar. Thrust- bearing is on forward length of line 

 shafting, and is a collar thrust. 



Thrust pilloic blocks are of cast iron, with phosphor-bronze boxes and 

 collar plates ; with set-screws to adjust wear. There is also a fore-and- 

 aft fastening to receive forward thrust. 



Line-shaft-piUow blocks are of cast-iron, with cast-iron caps, and fitted 

 with phosphor-bronze for lower half of journal. 



Screw-propellers are of cast iron, four bladed, 6 feet 8 inches diameter^ 

 12| feet mean pitch, and 20 inches in length fore and aft. They are keyed 

 upon shafts by a feather key and cross-key ; ends of shafts fitted with a 

 water-tight composition cap and fastened with composition tap-bolts to 

 after end of hub ; also, composition caps over ends of cross-keys. 



Shaft brackets supporting the after end of shafts are placed close to 

 forward side of propellers and are of composition. Section of brackets 

 I4 by Gi inches ; forward and after edges rounded off; feet of brackets 

 1\ inches thick, each foot fastened by four composition bolts 1| inches 

 diameter, with countersunk heads and screwed up on plates on inside of 

 ship. The eyes of the brackets are boxed to receive a phosphor-bronze 

 bushing 7^ inches diameter by lOJ inches in length, and bushing lined 

 with liguum-vitse, fastened to brackets with composition tap-bolts. 



Stern bearing is of composition, 2 feet 8 inches in length. The outer 

 end has a large warped flange, 1^ inches thick, to fit the counter of the 

 vessel, and the inner end a loose flange riveted to hull of ship. The 

 inner ends of the stem-bearings project inboard about 10 inches and are 

 fitted with lignum-vita". staves. The inboard stufiting-boxes are ofcom- 

 ]>osition, riveted to hull of vessel, with a packing space of 8 J inches, and 

 a loose ring fitting in bottom of i)acking space ; packing held in |)lace 

 by a gland also of composition. 



Sea-valves are screw valves, with composition chambers, valves, stems^ 

 and glands. One valve for injection, 4J inches diameter, one for circu- 

 lating pumps, inches diameter, and one for steam pump, 4 inches diam- 

 eter. Chambers bolted to cast-iron forms, which are riveted to hull of 

 vessel. All sea-valves are fitted with strainers. 



Hoisting-engine. (Plates V and VI,) — There is a hoisting-engine with 

 double cylinders and crank's at right angles to each other ; cylinders, {> 

 inches diameter and mches stroke of piston, placed forward on hurri- 

 cane deck for "trawling" purposes. The central drum holds the steel 

 wire rope and is independent of the engine proper, connection being 

 made by means of a friction clutch. The load on the drum is held by 

 a friction brake. With the central drum disconnected, the two smaller 

 drums can be used for ordinary hoisting purposes. There is also fitted 

 an automatic guide by means of which the wire rope is neatly coiled 

 upon the drum. Steam from either the main or auxiliary boiler may be 



