16 BULLETIN 300, U. S. DEPARTMENT OF AGRICULTURE. 
SPUDS. 
Spuds are heavy timber or steel] members, the purpose of which 
is to hold the dredge in position while operating. One is placed on 
each side near the front and the third in the center line of the boat 
at the stern. Vertical spuds extend directly downward at the side 
of the hull and rest on the bottom of the excavated channel. They 
are used on deep-water dredges or on those for excavating large 
channels. 
For a dredge with a narrow hull, bank spuds which extend out- 
ward and rest on the ground surface are preferable, since they give 
a large bearing surface and the footing is usually on solid ground. 
These are important features, as a longer boom and a larger bucket 
can then be used on a narrow hull. 
There are various patented bank spuds. One is the convertible 
bank and vertical power spud. This type can easily be changed 
from a bank spud into a vertical spud and is convenient in crossing 
old channels, digging cut-offs, or making a double cut. Another 
type is the telescopic bank spud, so designed that the spud is either 
lengthened or shortened by means of a telescopic device. There are 
other styles of bank spuds which, although they possibly do not have 
as wide a range as the telescopic type, can nevertheless be operated 
successtully several feet above or below the water surface. Plate I, 
Figure 1, shows a dipper dredge equipped with telescopic bank spuds. 
TABLE 6.—WSizes of spud feet generally used on bank-spud dredges. 
Capacity of! «. 
dredge. | “ize ofspuds. 
| 
Cubic yards.| Feet. 
33 by 43 
4 by 53 
5 by 6 
6 by 63 
a. bye 
Ti by 8 
} Ss by 9 
bi 
Ni 
OU Co DD DD 
A useful rule to remember for obtaining the distance from center 
to center of spud shoes on bank-spud dredges is to add from 3 to 5 
feet to the length of the boom. | 
The vertical spuds of various makes are more nearly alike. The 
rear spud is always of the vertical type and is used to keep the stern 
of the boat from swinging from side to side as the dredge is oper- 
. ated. It is equipped with an iron point instead of a foot. The spuds 
are raised and lowered by steel cables connected with the spud 
machinery. Compressed air is sometimes used to aie in releasing the 
foot of the spud from the mud; less power is thus required to raise 
