In this case the frictional resistance of the large hoop is necessarily
greater than that of the pin carrier of the older method. It can,
however, be lubricated with oil and attended to in a way that was
not possible with the pin on the sponson beam.
The working parts of the feathering gear of a paddle wheel should



DIMENSIONS OF PADDLE WHEELS.
8 9



have the pins cased with
hard bronze and the holes
in which they fit bushed
with lignum viUe. (See fig.
23.) The feathering pin
should be treated in the
same way, as it is always
being drenched with water,
so that no effective oiling
is possible.
White metal bushes
(Fenton's) with hard steel
pins can be employed satis-
factorily, especially in
sandy or muddy water.
Dimensions of Float
Fittings. — The diameter
of float gudgeons = O'l
x breadth of iioats + 1 inch.
Length of bush for gud-
geon = 1*40 x diameter of
gudgeons.
The diameter of radius
rod pins = 0*50 x diameter
of gudgeons.
The king rod should
have a double jaw support
to its pin and the float
gudgeons strengthened to
take the load of driving
the feathering gear.
The locus or path
of the paddle float
"centre 15 is shown in
fig. 24. The position of
the float or the angle it
makes with the vertical
at each point is clearly
seen throughout the whole
course, but the most im-







90 MARINE PROPELLERS.
