Public ledger. [volume] (Memphis, Tenn.) 1865-1893, 1868-12-31
rh. erss: Floating Dock for Bermuda.

This enormous maritime structure is
now completed. The following is con-
else history and description of the gigan-
tic undertaking:
The British Government, being i'm
pressed with the absolute necessity of
providing dock accommodations for the
iron.ciad ships and other vessels consti-
tuting the North American and West
India squadron, determined some time
since to build a cspacious floating dock
of iron for service at Bermuda. When
Admiral Sir Alexander Milne COM
manded on that station he pointed out to
the Admiralty this great want. During
the past ten years many iron-clads have
been added to our feet; and although
most of these have been payed below
water line with various compositions, the
hulls of most ships after service ahoat
were exceedingly foul. The iron men-of-
war on the North American and West
India stations were no exception, but
after shorter or longer time ahoat we're
more or less covered below water line
with barnacles, weeds and parasites, thus
impeding the speed of the vessel and
causing other annoyances.
The want of dock in the West Indies,
in which a ship could be laid up for
cleaning the bottom and for necessary
repairs, induced the government to con-
struct a monster floating machine at
cost of nearly $3.50, 900. This dock was
built by Messrs. Campbell, johnson d
Co., of the Albert works, Silvertown,
from plans patented by Mr. Campbell,
and adopted for the royal dockyard at
Bermuda by Colonel Clarke, Il. e the
government director of works. This
great iron floating structure, the largest
in the world, is OF the following dimeu-
sions: Extreme length, 38l feet; width
inside, SO feet inches; width over all,
l23 feet inches; depth, IA feet inches.
The weight of the dock is 1850 tons, and
it is asserted that vessel weighing
| 10000 tons or more may be easily lifted,
making the total approximate displace-
ment about l9, 900 tons.
The dock is U-shaped, and the section
throughout is similar. The iron-clad
Bellerophon, and ships of similar and of
smaller size, may be easily received into
this capacious hollow, and when once the
dock ia in position ships forming the
squadron on the West Indian station
will no longer be subject to great and
ever-recurring Inconvenience. 1t is built
with two skins fore and aft, at distance
of twenty feet apart. The plans show
that the space between the skins is di-
vided by water-tight bulkhead, running
with the middle line the entire length OF
the dock, each half being divided into
lthree chambers by like bulkheads.
The three chambers are respectively
named load" balance and "air"
compartments. The frst-named cham.
Der is pumped full in eight hours
when ship is about 10 be docked, and
the dock is thus sunk below the level of
the horizontal bulk heads which divide
the other two chambers. Water sufficient
TO sink the structure low enough to admit
a vessel entering is forced into the bal
ance chambers BY means OF valves In the
external skin. The next operation Is to
place and secure the csissous aud eject
the water from the load chamber
Then the dock with the vessel in Il rises,
the water 10 the dock being allowed to
decrease BY opening the sluicss IN the
caissona The dock is trimmed By
letting the water out Of the "balance
chamber into the structure itself The
inside Of the dock is cleared Of water By
valves in the skin, and il is left 10 dry.
When IL becomes necessary TO M
dock the vessel the valves IN
the external skins Of the "bslance" "
chamber are opened in order 10 gil them,
and the culverts 10 the caissons are also
opened, and the dock sunk 10 q given
depth. From keel TO gunvale nine main