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EXCAVATING MACHINERY USED IN LAND DRAINAGE, 57 
Muscatine, Iowa. The material was sufficiently hard to require a 
cutter head (Pl. XIII, Fig. 3). The mechanism for running the 
cutter head was operated by a vertical two-cylinder steam engine. 
For moving the dredge a 6 by 94 inch double-cylinder, three-drum 
hoisting engine was used, the cable being secured to a deadman on 
the shore at one end and to a heavy anchor in the river at the other. 
One drum was used to raise and lower the suction pipe. The hoist- 
ing engine used steam from the main boiler. For operating the 
pump a rope drive was used, the rope being four-strand and 14 
inches in diameter. Rope transmission is believed to be less affected 
by moisture than leather belting; moreover, there is less slippage 
with rope drive. 
The discharge pipe was carried from the dredge to the shore on 
barges, each 40 by 14 by 2 feet. The material was deposited on the 
levee through 4 by 6 inch openings in the bottom of the discharge 
pipe (Pl. XIV, Fig. 1). The openings were equipped with shutters 
(Pl. XIV, Fig. 2), so they could be opened or closed as desired. The 
discharge pipe was divided into 25-foot lengths, each of the last 
10 lengths being equipped with three openings or gates. The pump 
became clogged occasionally with masses of roots, and to prevent 
damage to the discharge pipe from the resuction in the pump a joint 
of pipe having a release valve which allowed air to enter (Pl. XIV, 
Fig. 3) was inserted in the pipe. Resuction will cause a 14-inch dis- 
charge pipe of 14-gauge material to collapse unless release valves 
are provided. The pump was equipped with pressure and vacuum 
gauges to enable the operator to gauge the working of the dredge. 
The operating crew for one shift consisted of a foreman, an op- 
erator, a fireman, and a deck hand. From 5 to 10 men were required 
at the end of the discharge pipe, depending upon whether an old 
levee was being enlarged or a new levee built. The coal consumption 
averaged from 4 to 5 tons per 1li-hour shift. When the condenser 
was not used about three-fourths ton more fuel per shift was needed. 
With steady running the dredge pumped from 2,000 to 2,400 cubic 
yards in 11 hours; on the job as a whole, however, the average was 
from 1,000 to 1,200 cubic yards per shift. 
« The open type of impeller with five blades was used on the dredge 
described. This impeller has adjustable shoes which can be replaced 
when worn. 
To build a hull for a dredge of this description takes 8 men 6 
weeks; to assemble the machinery, 6 men about 6 weeks; to build a 
coal barge 75 by 16 by 5 feet, and 5 pontoons, each 40 by 14 by 2 feet, 
will take 8 men 6 weeks. The cost of the dredge complete is about 
» $30,000, including barges and pipe. 
In excavation where many roots are encountered, it has been found 
that the inclosed impeller having two blades works exceptionally 
