Rock Island daily Argus. (Rock Island, Ill.) 1886-1893, 1892-08-19
SOMETHING ABOUT PRopellees
the Different Casualties That Rreax
Thesc Massive Castinps

inc Dinerent Casualties That Break
These Massive Castings
propeller OF a steamer is q compara-
tIVeIy insignificant object compared with
.ne huge body 1T propels against the com
~ icrces OF wave and wind, but they
49, W srieI frequently in variety of
ways few days ago the red d steamer
venezuela, in calm sea. without brestb
VI wihd almost, suddenly lost one blade of
reI screw Just as suddenly and with as
'ie ciuse or notice as overripe fruit
drops from its parent bough.
Around the dry docks are numbers of
eiSantlc propellers, all in one stage or other
u uii'Piuatlon. Some are cast in the solid
.1hat Is to say, the hub through which the
smart passes and the fans which extend
from 1t are one solid casting Others are
ouii1 or cast, rather IN sections; the hub is
one, ana each fan or blade is another
wnlch mt into bases made for them in the
huD, where they are screwed on by hinge
poi1s 1hat are set in the hub casting
mere one fan or blade is broken it is
easily replaced, as the makers retain the
models of all wheels or propellers. as they
are indifferently called, which they cast.
linen The entire wheel is not rendered use
less, as IN the case when solidly cast pro-
peller like the Nenezuela's comes to grief.
1t Is extraordinary to see the proportion
OF vessels that arrive having received some
damage to their propellers. Occasionally
damage is done by the shaft racing, as it is
technically called That is caused by the
steamship plunging head on into the trough
81 big sea, and so elevating the stern and
the propeller that it is completely out OF
water, and being suddenly rid of the re-
slstance the engine runs away, so to speak,
just as an ordinary engine will do when
driving belt slips off or breaks. Occasion
ally propellers are broken by striking
or md 1x- Nv, IL;
a whale or large fish, when it is so much
the worse for the fish.
But there is one curious fact ALWAYS
noticeable about propellers; that is, that
the eXtremities of the blades are eaten
away as though by some corrosive acid
They are pierced with holes of greater or
lesser depth. which weaken the points of
the fans SO that they snap off. these
corrosions are said to be caused by the
action of the water, but it seems strange
that the wearing should take the form Of
honeycombing the metal instead of wear
ing it away smoothly, as the mere friction
of striking the water might be supposed
to do
Recently screws or propellers are made
OF different ombinationS of brass and
other metals, especially for steam yachts,
and are very costly. a short time ago
Plerpont MorCan's yacht struck a rock in
the sound. The force of the blow smashed
one blade clean off, although fastened on
by eight or ten pinch bolts secured by
massive nuts, and Il second blade was curled
up by the blow just like sheet of lead
This wheel was designed by Beaver Webb,
was only a three bladed one and yet it
cost the comparatively enormous sum of
$500. 1t WAS made OF i composition
metal resembling brass in color, called
Manganese bronze.
In large ocean steamships, if the pro-
pellers are not one solid casting it is usual
to cover the nuts and bolt points which
fasten the fans to the hub with a cement
This is so tenacious and becomes so hard
when once set that it rarely breaks until
its removal becomes necessary, when it
gives the workmen a hard tussle to re-
move it.-Brooklyn Eagle.