SCREW PROPELLERS.

Soon after the Act of April, 1871, to foster and develop the inland

commerce of the State, the steam canal-boat _Cathcart_ was tried. She is

like the _Niagara_ of 1859, and has not been continued in the trade.

The canal-boat _George Barnard_, afterward called the _Andrew H. Dawson_,

was tried, and has run through the season of 1872. She has a common

propeller in her bow, with a recess from the water-line inclined to twenty

feet aft to the bottom. Her propeller, therefore, forces the current

against this incline and along the bottom in retardation of its progress.

Hence, she cannot be expected to excel former trials.

The _Eureka_ is an iron boat, built at Buffalo, with twin-propellers at her

bow, set in recesses, at a diverging angle, to throw the water from the bow

along the sides of the boat. She is built, by men of canal experience, with

compound engines, and was designed to be a superior boat for canal

purposes. But her _mechanical currents_ at and against the bow must have a

retarding tendency, not compensated by any other considerations.

The _George A. Feeter_ is also a twin-propeller, with diagonal, channel

waterways on each side for about twenty-five feet, when they merge into a

larger channel about five feet forward of the rudder. Her propellers are

set in these channels, about ten feet aft of their side openings. With her

propellers thus housed, the mechanical currents against the aft-sides of

her channels are very damaging to her efficiency.

The _Wm. Baxter_ is also a twin-propeller, like the _P. L. Sternburg_, of

1858, and with compound engines, like the _Eureka_ and the _Dawson_. She is

built of yellow pine, with easy lines, and so low as to be unable to carry

five-sixths of a horse-cargo of wheat or corn below deck, so that her

lightness gives help to cargo, and her sharp bow and stern to speed. But

her construction and model were long since abandoned by canal-boat

builders.

The _Wm. Newman_ is a common propeller and double-deck boat, and carries

two hundred and ten tons. She is much like the _Ruggles_ of 1858, but has

less steam capabilities.

The _Charles Hemjee_ was built upon the Western Division, with a

tunnel-shaped encasement to her propeller. Of course she is reported as

"very slow."

The _John Durston_ had a propeller built in with her rudder, and driven

with a vertical shaft, extending down through a cylindrical rudder-post,

but was unfit for service.

History of Steam on the Erie Canal · 第 7 / 19 题