The silver messenger. (Challis, Idaho) 1890-1912, 1902-02-18
BIG FLOATING DOCK
BUILT AT BALTIMORE TO BE
TOWED SOUTH.
Immense steel Dry Dock for Use at
AlRiers, La.-Its Use Is to Lift Great
Vessels Out of the Water.

Baltimore correspondence, Chicago
Journal: Down at Sparrows Point,
completed all but a few finishing
touches, lies the great steel floating
dry dock built by the Maryland Steel
company for the United States govern
ment, and which is to be towed to AL
giers, La, as soon as the West India
hurricane season has passed. That
will be about Oct. l. and several pow
erful ocean-going tugs will convey the
immense dock to its destination. 1t
is certain that this immense piece OF
marine mechanism for lifting great
vessels out of the water in order to
clean or repair them is without a SUI
perior in it's line, and it is doubtful
whether it has an equal. 1t can raise
a 1 5,000-ton battleship and have the
foorof the deck two feet above the wa
ter, which is demanded by the govern
ment for it's work, but with the floor
even with the water line it can lift an
18,000-ton ship. The dock is 525 feet
In length over all, while its breadth is
exactly 1876 feet 2 7-16 inches. The
width between the sides is 100 feet.
The entire height of the sides, from
their bottoms, which are submerged, to
the tops, is fifty-five feet. The depth
of the pontoons, or what the inexperi-
enced might call the hulls OF the docks,
is seventeen feet six inches. The
greatest draught of the dock is forty
nine feet six inches. There are three
pontoons, which form its floor and also
with the sides, give it buoyancy. The
middle pontoon is the largest, being
242 feet long, and the end pontoons are
each 141 feet as inch in length. The
walls are 1896 feet Is inch long and are
nine feet in width at the top and thir-
teen feet at the bottom. The pontoons
and sides are divided into forty water
tight compartments, which enable the
dock to be completely under the con-
troll of the dock master, who can make
it assume any position required to
dock a vessel. 1t has 261 keel blocks,
upon which the vessel rests in the
dock, and they are movable, so that
they can be readily adjusted. The
weight of the steel in the dock is 1865
tons, and the weight of the dock equip
ment is 1000 tons, making a total
weight of 6,865 tons. The cost of the
dock complete is 500, 900. The stabil-
ity of the structure, according to the
engineers figures, is something re-
markable. Carrying a Is, 000-ton battle
ship two feet above the water, it will
cause her stability to be fifteen or
twenty times as great as that of a ship
in the water. The numerous compart-
ments add to the steadiness of the
dock, for, if they were few in number,
the water in them when the dock was
submerged or partly so, would splash
about and cause considerable motion
to the structure. When it is necessary
to dock a vessel water is admitted to
the compartments through sixteen
valves, each sixteen inches in diam
eter, and it requires about an hour to
sink the dock so that craft can enter
it. After the dock is sufficiently deep
in the water the vessel enters, and,
having been accurately adjusted. the
water is pumped out of the compart-
ments by means of eight pumps, which
are driven by four engines that have
-four boilers of the water-tube type and
of 1876 horsepower each to supply
them with steam. The pumping ap-
paratus is so arranged that either en-
CINE can steam from either boiler, and
in case there is a breakdown on one
side of the dock the pair of pumps on
the other side could do all the pump
ing. 1t takes about three hours and a
half to raise the dock. The pumps
also operate a line of hose, which is
employed to wash the slime from the
bulls of vessels that are locked. This
is quite a task, for the amount of foul
ing which is washed from the sides of
a large ship is considerable, and after
it has been cleaned the stuff has also
to be washed from the floor of the
dock, otherwise the men could not
work about the craft.