The Sun.
London, England, 1858-09-27 00:00:00

FLOATING DERRICK MACHINES.

On Saturday the launch of an iran vessel of most
singular form and construction took place from the
yard of the Thames Ship-building Company, Black-
wall, and created a great deal of interest, not only
amongst nautical and scientific men, but amongst
the population of the neighbourhood.
One would naturally infer, on learning a vessel had
been launched from a ship-building yard, that it
possessed some of the characteristics and was de-
signed for some of the uses of an ordinary ship;
but such a conclusion would be quite erroneous in
the present instance, for our vessel has neither
stem nor stern, nor paddle nor screw, nor mast nor
tackling, nor any of the usual accompaniments of
barque, sloop, or steamer. In sliape it has not the
graceful,' gradual swell of a ship ' • neither is it
circular, elliptical, or quadratic in form. It is a
floating rhombus, and if one were to speculate, a
priori, on its possible uses, the conjectures which
might be formed on that head would seem to be
inexhaustible. If peace had not just been concluded
with the Celestial Empire, the vessel would cer-
tainly be considered a gallows for the use of the
piratical floating population of the Canton river,
and the appellation " Derrick," which was the
name of a notorious Tyburn executioner in the
early part of the rith century, would have given
vralsemblance to such an ingenious hypothesis. It
might also, without much eccentricity of hypothesis,
be taken for a telescopic apparatus expressly for
observing the comet, or fora floating light-house,
or coal depot in mid-ocean ; for a Sartorius shot-
proof battering ram; for a strange whaling ship,
or fora ,satellite of the Great Eastern, with which
wonderful vessel it will divide the curiosity and
speculation of the Thames travelling population.
The floating Derrick has been constructed, how-
ever, for the very practical and useful purpose of
raising sunken vessels, and its invention is due not
to the fanciful projectors of Lagado, but to the
practical engineers and ship-builders of New York.
To Mr. Bishop, an ingenious American, is due the
merit of the invention.

For some years past it has been extensively em-
ployed in the United States as a transportable or
moveable apparatus for raising heavy stones for
masonry, such, for instance, as that of the cele-
brated High Bridge, which forms a part of the
aqueduct for carrying the supply of Croton river
water to New York. It has also been very gene-
rally used as a stationary machine for wharves and
piers, and in hoisting boilers and machinery into
ships fitting for sea, and in dismasting and remast-
ing vessels of all sizes. At the Brooklyn Navy Yard
of the United States it has superseded for this latter
purpose the old form of " shears." Lastly, the
principle has been applied on floating vessels for the
purpose of raising sunken ships. It was in the last
of these applications that the Derrick was intro-
duced to our notice on Saturday. In various parts
of the United States 16 of these machines—trans-
portable, stationary, and floating, possessing a hoist-
ing capacity of over 2,300 tons—have been con-
structed and worked for several years, to the entire
satisfaction of the parties owning them. Two of
these were erected for the United States Govern-
ment, and of two others belonging to the New York
Derrick Company, one had raised and saved nearly
400 sunken and stranded vessels, while the other
had hoisted and. placed on board the engines and
boilers of over 300 steamers. A short time since
the Ericsson steam-vessel,: of 2,300 tons, which, it
may be remembomd, was to have accomplished such
important revolutions in marine locomotion by
means of heated air, was raised by means of this
machine, the vessel laying unfortunately sunk, with
all its machinery, off the coast of New Jersey.
The merits of the machine, therefore, have been
fully tested, and it is now introduced into the coun-
try by means of a company formed under the Li-
mited Liability Act, called the " Patent Derrick
Company (Limited)," The necessity which existed
in England for a machine of such a-character is evi-
denced by the fact that the total number of casual-
ties reported as occurring last year in this country
was 1,141, representing a burthen of 176,544 tons
of shipping and steamers combined. Of these 1,141
vessels wrecked on our coaststhere were 963 British,
110 foreign, and 11 colonial. It is calculated that
very nearly 800 out of these 1,141 vessels could have
been raised and saved, had such a fleet of these
Derricks existed as it is now sought to construct
and organise by means of the present undertaking,
upon a capital of £250,000. . . _

-- The. vessel, or rather the machine, consists of
a hull or " scow" of a most singular construc-
tion. If our
.readers will imagine a square iron
surface each side of which is 90 feet in length,
or 10 feet wider than the Great Eastern steamer,
and upon each of two opposite sides of this square
will construct an equilateral triangle, they will then
be able to form an approximate idea of the level
surface of the deck of this extraordinary " scow."
The proportions will not be quite correct, hut pretty
near, the exact figures being for the length of the
hull or " scow" 257 feet, and its greatest width of
beam 90 feet. Both stein and -stern are precisely
alike in form ; they are wedge-shaped, the greatest
width being at about 45 feet from the centre or
midships. This hull is wall-sided or perpendicular,
and the bottom—perfectly flat—is of course of the
same dimensions and area as the deck, and the
depth of hold is 14 feet. The hull is formed entirely
of water-tight compartments, and strengthened by
being constructed upon the cellular principle. In
order to secure additional strength a wrought iron
arch, formed of plates of iron, passes from stem to
stern—or rather from one end to the other, for,
properly speaking, the thing has neither stem nor
stern--and fastened by upright and diagonal tie-
rods and supports; and two arches similar in con-
struction cross the ship diagonally, and intersect
each other in the centre of thelength and breadth
of the " scow." The largest of these cast-iron ellip-
tical arches has a span nearly as great as the centre
arch of London-bridge. Within the hold of the
" scow" are placed two propelling steam-engines,
and two others for working the gear for raising
the ships. The huge thing will be moved slowly
by means of a revolving chain passing over two '
large wheels placed on each side, and-provided with
moveable floats, something in the manner of the
buckets of a dredging machine, and which fall as
they descend towards the water. This chain and
floats revolve in a sort of channel or sewer, nearly
90 feet in length, protected by the outer iron plates
of the vessel's side, and which dip below the surface
of the water. There is a rudder at each end, but
the " thing" will carry no sails, and when required
to be moved will have to be towed to its destina-
tion. The " scow" or hull possesses a dead weight
of 750 tons. From its pecnliar construction the
" scow" has a very light draught of water, not exl-
ceeding 30 inches. When launched: on Saturday
it was necessary to pump 300 tons of water into
the hull to keep it sufficiently steady under the
weight of its top-gearing.
On the basis of this enormous float the Derrick
crane, or hoisting apparatus, is fixed. It consists
of five iron legs, formed of inch-and-a-quarter plates
of iron, which support, at a height of 50 feet, the
enormous hoisting " boom." This boom is 120 feet
in length, and its broadest part is 30 feet in breadth.
It is formed of thick plates of iron i'lvetted together,
and which, seen from below, appear as though one
of the Thames steamers had been taken up bodily
and placed in the towering platform above.
Through a hole in the centre, this forming the pivot
upon which the boom turns, is the great " king
post," in the interior of which a game of chess was
recently very conveniently played. The height of
the post above the " boom" is fifty feet, and it is
surmounted at the top by a huge block of iron
weighing twenty-five tons, to which the
ichainswhich support the ends of the bboom"a
at-
tached. The legs, which support the whole of the
weight, are firmly secured by braces and diago-
nal ties. The total heigh,t, from the deck to
ofitshel3doun. feet
tions Theand
the top
areofthtehe;cairtnigcuiparosst
following
weight of the various parts of this extraordinary