, 1898-09-10

it would seem next to impossible to get buck
to the surface of the water a huge vessel
weighing thousands of tons. her hnIl gaShed
by the impact of collision or torn by the sharp
points of rocks. Yet nowadays this feat is
performed frequently and with comparative
ease. owing to the improved machinery md
appliances placed at the disposal of the sal
wage companies which undertake such work.
The principal factors upon which depend
the Feasibility or otherwise Of raising a sub
merged ship are the position in which she
lies and thu depth of water covering her hull,
if the Inflated craft has gone down upon u
fairly hard bottom, the difficulty is greatly
lessened, and even if she is upon mud the
task is by 10 means an Impossible one. But
IT she is upon loose, shifting, or quick sands,
every tide tends to cause her to sink further
and further; and in the event Of bad weather
delaying the commencement of operations for
any length of time, so great is the retaining
power OF the sand that it is usually found he.
yond human owe to reloat her. II is the
depth of water, however, that decides the
question more definitely. Generally. speak
ln5 divers cannot work ut q level further
tn IN soft. below the surface, owing to the
great pressure that is encountered as they
descend; and therefore when a wreck lies
more than ten fathomS down her recovery is
rarely attempted.
In raising a sunken vessel the first thing
to be done is to patch up temporarily the
hole or holes in her hull. Divers so d wn.
taking with them the necessary ;ools and
materials, together with electric lamps for
Illuminating purposes. When they report
that The hull is repaired the nsxt process is to
Wect upon the deck u superstruCture, gene.
rally OF wood, which Cases in almost the
whole of the upper works Of the vessel, nnl
constitutes a huge watertight compartment.
AS soon as this Is completed powerful tugs,
provided with enormous centrifugal pumps,
capable Of dischargimg many thousands of
tons OF water pr day, COme upon the scene.
The pump-suction pipes are coupled mp to
the ship, and she is soon cleared of water.
Directly this is doue the vessel becomes suf-
%hclently buoyant to fl at to the surface, and
she IS then towod to the harbour, where her
inquiries are permanently repaired.
Another method sometimes used is TO SILK
aIongsll e OF the ship n number of large pom
to0ns-hoiiow cylinders of iron or steel
which are secured to The hull. Their wat ~
contents are pumped ont and the busyancy
which they then possess serves to raise the
wreck. The use of this plan, however is usually
c%ogfnel 10 Nmul vessels, which in some cases
have been Lifted by the main force Of power.
fl era es working from barges or pontoons
moo'ed over the spot.
Recent years have witnessed some notable
achievements in rrAoating sunken ships,
sometimes IA der very difficult circumstances.
In 1889 her N%Iaiesty's ironclad Sultan. of
over 5000 tons. and heavily armOured.
struck on some rocks in the Comino Channel,
which divides two Of the islands of the
Maltese group. This occurred in the month
of April. aud at first it was thought that it
would be fruitlesS to attempt to raise her.
However. after some hesitation, the British
Government resolved to make the effort and
send the necessary appliances 10 the scene
OF the accident. All the Sultan's guns,
stores, ammunition, ard ms many of her
heavy fittings us could be got out were
removed by the divers before The real work
of raising the wreck began. The difficulties
encountered may be Judged from the fact
that the task occupied Il period of four aud
a half months. At last the hull was repaired
md rendered watertight and was then
pumped dry, and on Aug. 20 the vast struc-
ture was successfully lifted. She was lowed
to Malta, and subsequently returned to
England. A few years ago she received new
engines and boilers, and no one who sees
the Sultan, a splendid specimen Of the Older
fashioned type of ironclad, would imagine
now that she had spent so long a time ut
The bottom of the sea.