The Wichita daily eagle. [volume] (Wichita, Kan.) 1890-1906, 1892-03-08
MATERIALS USED IN SHlPBUILDlNG
AND THEIR VALUE.

for wood is unsrlited to the great engine
| power nowadays put into ships; 1t can
not properly stand the strain.
Iron ships are superior to wooden ones
in the following particulars: Lightnes:
combined with strength, durability wher
! properly treated. ease and cheapness OF
construction and repair and safety when
| properly constructed and subdivided. In
wooden ships it has been found that
about one-half Of the total weight of the
| ship is required for the hull, whereas in
iron ships only from 80 TO 40 per cent. OF
the weight is thus taken up. For in
stance, in a wooden armored warship,
the weight Of the hull being 50 per cent,
of the displacement leaves so per cent.
for the weights to be carried. In an iron
armored warship the weight of the hull
is only 10 per cent. leaving 60 per Ger
for weights to be carried.
The tensile strength Of iron is fro1
10000 pounds to &C, 900 pounds per squar
inch, and this strength can be secure
throughout all the metal used, so tn
the material worked into the ship is un
form and homogeneous. These are quail
ties wanting in wood; the greatest care
cannot eliminate such weak spots as are
due to the presence of knots, crossgrain,
hidden defects, etc. Generally good
sound timber may be said to have a
strength to resist pulling apart (tensils
strength) OF about 10000 pounds.
IRON FAR SUPERIOR TO WOOD.
When in shipbuilding it comes to
fastening pieces together, as, for in
stance, in making a ships keel or her
deck beams, the weakness caused by
soaring the pieces Of wood together be-
comes an element Of strength in riveting
the iron. No matter how it may be nee
esssary to treat the pieces of metal,
whether by rlveting or welding or by
angle irons, the iron stands far above
the wood In resistance to tensile strains.
1t Is only when resisting strains of CON-
preston that there is tendency of iron
plates to buckle, and this is guarded
against by making the plates thicker
than is required for other strains or by
reinforcing them.
Durability is quality of iron that is
not yet thoroughly determined. In gen.
eral, wooden ship may be said to last
about fifteen years. Some last longer
but there will be much patching and re-
newing to be done. The rules of Lloyds
allow about fourteen years as the aver
age durability of the best built timber
vessels.
Iron is not subject to the internal
sources of decay to which wood is liable
Worms and marine animals cannot in
Jure 1t, nor will it rot from imperfect
ventilation. Neither can the parts work
loose from the motion and straining of
the ship, allowing water to get in and
cause decay. The danger to iron lies IN
the rusting or corrosion, especially in
the under water parts-outside from the
sea water and inside from the bilge
water. The only prevention is careful
watching, cleaning and painting. and
even with all this supervision galvanic
action is likely to do some damage.
Therefore the life of an iron ship is linn
tied, and in the present state of knowl-
edge OF the subject may be set down as
approximately thirty years, for, though
a ship will last longer, extensive repairs
Will have to be made that will cost con-
siderable money.
STEEL BETTER THAN IRON.
1t is also easier to repair an iron ship,
since the necessary shape can be turned
out at once. The rapidity with which
an iron ship can be built counts for
much. In the present day the ease with
which iron is obtained and worked con-
stitutes another element of cheapness
for the final cost today must amount to
nearly % per cent. less, especially when
the time, preparation, saving of weight
and life of the ship are considered.
As to the safety of ship when prop
erly constructed and subdivided, it is
only necessary to say that when the in
ternal space of an iron ship is sub
divided into many compartments by
longitudinal or transverse partitions
rising TO sufficient height, or by hori-
zontal platforms. or inner skin, and all
such divisions are made water tight, then
that ship is safer than any wooden ship
would be against laundering, for the
space required for these bulkheads can
not be found In timber built vessel.
The subject of steel may be briefly dis |
cussed by remembering that steel is sim |
ply a superior kind of iron, and BY vir- |
tue of Its greater strength IS of lighter |
weight. The strength Of steel Is from |
10000 to 100000 pounds per square inch. /
Steel Is as strong lengthwise as II is |
broadwlse; iron Is one-hfth stronger
lengthwlse than 1t is broadwise. The /
elastic limit of steel is about % per /
cent. greater than that Of iron So steel |
may be trusted with working loads
nearly p per cent greater than the 9TH !
er material. Lloyds estimate that by /
ships OF steel there is a saving /
In weight over iron of about 10 per cent. /
Dr., to put the same thing In another |
way, steel ship Of the same dimensions /
IS an iron ship would have an increased |
cargo capacity On weight Of some 10 or
20 per cent.
In the matter Of cost. steel is more ex.
oenslve at first. but the best proof of its +
ultimate cheapneSs Is found in the in
iisputable fact thst modern merchant I
ships are beng built Of steel. In 1890 /
there were 500 steel ships built. % iron
and - composite and wood. There need /
he no further argument as 70 the su-
periorlty OF steel from every point OF /
Tlew.-New York Tinez
TWO REMARKABLE PREACHERS
W nat One Thinks About the Bible-The