44 REPOET OF COMMISSIONER OF FISH AND FISHERIES. [42] 



rapidly in the ship, aud there is an absence of odors peculiar to ships, 

 of the "stuffiness" in the sleeping apartments, and of the sensation of 

 headache and nausea on waking in the morning. 



STEAM CUTTERS. 



The Albatross is provided with two steam cutters, built by the Her- 

 reshoft" Manufactaring Company, of Bristol, E. I., from their own de- 

 signs. The boats have wooden hulls, the larger one being coppered; 

 both are fastened with screws, and are built as light as is consistent 

 with strength. They have compound engiijcs, Herreshoff's patent coil 

 boilers, aud external surface condensers. That which distinguishes 

 Herreshoff's system is the coil boiler fed at the top, emptying its 

 steam and Avater into a separator (whence steam is fed to the engine), 

 and a "circulating pump" which takes the excess of feed- water from 

 the bottom of the separator and delivers it again to the top of the coil. 

 The larger boat has its shaft parallel with the base line and has a 

 4-bladed screw ; the smaller boat has its shaft inclined, passing through 

 the bottom of the hull, a little to one side, and about amidships, and 

 has' a 2-bladed screw ; just outside the hull there is a universal joint in 

 the line shaft, which permits the screw being pulled close up under 

 the bottom of the hull, with its two blades lying horizontally, in a recess 

 left in the keel, and when thus placed the lower edge of the keel is 

 below the edges of the screw. The object of this is to protect the screw 

 when passing over shoals. The screw being placed under the bottom 

 of the hull, works always in solid water, and no matter how rough the 

 sea, the propeller is nev^er thrown out of water, and does not "race." 

 Fig. 16 is a cut of the double- coil boiler of the steam cutter. The feed 

 water enters the bottom of the outer 

 coil, passing upward and through the 

 spiral coil, then into and down the in- 

 ner coil, and finally up, through au 

 external pipe F, and into the sepa- 

 rator D. The gases of combustion 

 pass through the spaces between the 

 coils. The furnace is lined with fire- 

 bricks to a height of about 6 inches, 

 and the coils are supported by wrought 

 iron straps, with stirrup bolts, resting 

 on the* fire-bricks; the casing of the 



boiler is of sheet iron. The lightness of the boiler, the very small 

 amount of water it contains, its great strength, and large heating sur- 

 face give it great advantages over other boilers, and its results have 

 been admirable. The boiler of the smaller boat is similar to the one in 

 Fig. 16, except it has not the outer coil. 



Fig, 16. 



boiler, the 



