A ship cast ashore always reminds me of a hospital ward and the men and
women who are deprived by illness of the power to carry on the struggle
of life. The ship, too, is a cripple, driven out of her element, unable
to carry on the duties for which she was created, and this is why my
curiosity in a case is always tinged with a little sadness. To the
salvage expert, however, the beached ship is merely a problem, and his
mind, like that of the physician, is wholly occupied in effecting a
cure.
If straightforward towing will not get the ship off, he will try other
means. He may set a gang of men digging a deep trench round the keel
of the vessel at low tide, and as the tide rises the water, flowing
into this trench, will give her just enough buoyancy under her keel to
enable the tugs to do the rest. Or he may try a trick that was tried
very effectively on one occasion during the war when a whole convoy of
ships grounded during a fog. The salvage officer, when his tugs failed
to shift them, set torpedo boats thrashing round at a high speed and
the wash they created lifted the grounded ships sufficiently for the
tugs to get them off. It was a simple, yet clever, solution to the
problem.
But there may be factors in the case which make these methods useless,
as happened when the s.s. _Timbo_ was thrown ashore in Carnarvon Bay in
1921. She drifted at the mercy of a terrific gale, which was blowing
dead on the shore. Lifeboats that put out to succour her were swamped
by the enormous seas, and more than one brave man lost his life that
stormy day before the _Timbo_, absolutely helpless, was driven right
across the bay. Just when tide and tempest were at their height, she
was caught up by a tremendous wave and thrown heavily ashore.
That tide happened to be exceptionally high, and when Mr. Henry Ensor
came on the scene he found a strip of shingle just 100 feet wide
separated her from the sea when the tide was at the full. There she
lay, broadside on to the ocean, and over 30 yards beyond the reach
of the largest comber that rolled up the beach. She was indeed out
of her element, so much so that 30 yards or 30 miles would have made
no difference to the average city-dweller, for to him the problem of
getting her back would have been insuperable.
[Illustration: BY DIGGING A DEEP TRENCH ROUND THIS WRECK, THE SALVORS
MANAGED TO TOW HER OFF INTO DEEP WATER]
To tow her off on a beach like that was not to be thought of, for
if tugs had been set to work they would merely have added to the
difficulties. Directly they began to haul, the stony beach would
have heaped up under the weight of the steamer, and the more they
pulled, the deeper the wreck would have burrowed into the beach.
[Illustration:
_By courtesy of H. Ensor & Sons_
THE TIMBO, CAST ASHORE A HUNDRED FEET ABOVE HIGH WATER MARK, WHERE SHE
WAS THROWN DURING A TERRIFIC GALE. SALVORS PROPPING UP HER BILGES TO
PREVENT HER FROM FALLING OVER BEFORE THEY STARTED THEIR STERN STRUGGLE
IN THE DARK]
The first thing the salvage expert did was to put timbers under the
bilges of the steamer to prop her upright and prevent her from falling
on her side. Then, using lifting jacks, he gradually raised her and
placed launchways beneath her keel to prevent her from burrowing into
the shingle when the tugs started to pull her off. This work was
completed just before the highest tide there was likely to be for some
time, and rather than miss this tide the salvors started to get the
steamer back into the sea in the dark.
Inch by inch they hauled that steamer across the intervening shingle
until half the space was covered, until the seas lapped the launchways,
splashed the keel. It was a tremendous fight. The tugs were hauling to
their last pound. Slowly the launchways disappeared into the water and
at last the salvors felt the _Timbo_ tremble. Another long, strong pull
and the steamer rose to the swell. Success had crowned the efforts of
the salvage specialist.
Refloating the _Timbo_ was a fine piece of work, just as was the
raising of the steamship _Fleswick_ with compressed air by the same
expert, many years ago. But in raising the _Silurus_, Mr. Ensor
accomplished a feat that ranks with the finest wreck-raising feats
ever accomplished. The _Silurus_ was a dredger, one of the most
powerful ever constructed. Built for duty in the port of Bombay, she
was completed about eighteen months after the outbreak of war. As it
was considered far too risky to attempt to tow her out to India at that
time, she was taken to the Gareloch, where enemy submarines were not
likely to penetrate, and anchored until such days as peace returned.
She had been serenely sheltered in that haven on the Scottish coast
for nearly a year, when dirty weather sprang up. In the ensuing gale,
she dragged her anchors and was driven hard ashore. Had she remained
upright, a tug might have remedied the matter in a simple fashion
when the tide rose again. But unluckily she grounded on a very steep
shore, which shelved away rapidly, and as the tide dropped she capsized
and buried her funnel so deeply in the mud that she was all but
upside-down. The top of the tower carrying the dredging buckets was
thrust into the bottom of the Gareloch, and while the tower tended to
pull her over, once she had overturned, it no doubt prevented her from
finishing with her keel right in the air.
As in the cases of the _Onward_ and the liner _St. Paul_, the problem
was to right the ship before she could be pumped out and raised. But
with the _Silurus_, the difficulties were increased by the top hamper,
consisting of the tower with the dredging buckets.
[Illustration:
_By courtesy of H. Ensor & Sons_
THE CAPSIZED DREDGER SILURUS, WITH TIMBER FRAMING ERECTED ON HER HULL
TO PREVENT THE STEEL ROPES FROM CUTTING RIGHT THROUGH HER]
[Illustration:
_By courtesy of H. Ensor & Sons_
THE WONDERFUL TANGLE OF WIRE ROPES AND GREAT BLOCKS THAT WERE USED TO
PULL THE SILURUS ON TO AN EVEN KEEL AGAIN]
Mr. Ensor, as unlike a miracle-worker as any one could imagine, went
to the Gareloch and quietly looked over the sunken dredger. She was a
big problem, but not too big for him to tackle. Moreover, he had the
courage to back his ability with his own money. Calmly he offered to
salve the vessel on the usual “no cure, no pay” principle. It meant
risking quite a fortune, but this did not worry him.
Then he began to get out his plan for righting the vessel, the
intricate calculations such a plan involves being not only amazing,
but perfectly incomprehensible to the average man who is not possessed
of engineering ability. He calculated on obtaining 1000 tons of
lift by pumping compressed air into some of the compartments of the
overturned vessel, and looked to pontoons attached to the tower and
other parts of the structure to aid him in his plans. But, for the real
work of pulling the ship over, he determined to rely on the power of
steam-engines operating on the shore and hauling on a series of giant
steel cables attached all along the ship.
The risk of pulling the ship to pieces in a job like this is so great
that the novice would drag the ship apart far quicker and easier than
he would drag it upright. If a cable were placed round the hull and a
powerful steam-engine given full play ashore, that cable would crumple
up the steel plates and gradually cut through them like a wire through
a cheese, instead of moving the ship. These were the risks that had to
be avoided.
Divers started to strengthen the ship with gigantic logs, 12 and 14
inches square, in order to withstand the terrific strain. A huge,
strong frame of similar logs, protected by steel grooves, was fixed to
the hull, to prevent the cables from cutting the ship to pieces.
It was slow work, for the salvors could only devote time to the wreck
when there were no important war jobs to claim their attention.
However, they managed to get in a day now and again, preparing for the
great tug-of-war, upon which depended a fortune. Materials were not
easy to obtain owing to the demand for munitions at the Front, so the
salvors had to make shift with anything that would serve their purpose.
The divers, who set to work with hacksaws to cut holes through the
steel plates for the passage of some of the cables, were greatly
handicapped by the rust and mud, which made the water so cloudy that
the work was difficult to see. Yet they stuck to their job and slowly,
monotonously ate a way with their saws through the metal. Then they
took up the task of preparing the seabed for the ship to come over on.
She was practically lying on a submerged hill, and about a thousand
yards of the seabed had to be removed to make a flat table on which the
ship could rest in safety without slipping over again. All this took
time as well as money.
Then it was necessary to find something ashore that would withstand the
pull of the ship when the tug-of-war started, something that would be
absolutely immovable while nearly 2000 tons was dragging on the ends of
the hawsers. The salvage expert tackled this difficulty by getting four
old boilers, sinking them into pits dug down to the rock, and filling
them and the space about them with concrete, thus making them as solid
as the rock on which they stood. These boilers were in this way turned
into four bollards, each capable of resisting a pull of 200 tons. Then
a propeller shaft, 12 inches in diameter, was cut into suitable lengths
and from it eighteen more bollards were made and set hard in concrete,
each bollard being capable of withstanding a pull of 100 tons. These
were placed at various intervals on the shore opposite the wreck, and
by the time they were ready the salvors began to juggle with some 10
miles of steel cable, from 6 inches up to 8½ inches in circumference,
that had been specially made by Bullivant, whose cables have dragged
many a ship back into her element while making a snug sum for the
salvors.
If there is any special work to be done, any heavy weight to be lifted,
the salvage expert the world over knows he is safe with Bullivant’s
cable, that it will not break at the psychological moment and let him
down. Some of these cables made of twisted strands of steel wire are
12 inches round--as thick as a man’s leg at the calf--and they will
support without breaking a weight of 320 tons: 320 tons could dangle
from this cable in the air and a man could stand under it in perfect
safety.
The largest hempen ropes made for salvage work are up to 24 inches
round, even 25 inches on occasion, so it can be imagined how difficult
they are to handle. If 1 foot of a 25-inch rope were cut off, it would
be more than most men could lift, for it would weigh 146 lb. A short
length of 15 feet would weigh practically a ton. A rope of this size
will withstand a pull of 125 tons, against the 320 tons of a 12-inch
steel rope. It might be thought that a rope half the size would support
half the weight, but a peculiarity about hempen ropes is that, while
a rope of 4 inches will support 4 tons, if you treble the size of
the rope to 12 inches you increase the breaking strain by more than
sevenfold to 29 tons; double the size of the rope again to 24 inches
and it will support just four times the weight of the 12-inch rope,
or 115 tons. Similarly, the bigger the wire rope, the bigger the load
it will take in proportion. Whereas a 4-inch steel cable will support
35 tons, an 8-inch cable will carry 150 tons, or nearly five times as
much, while a 12-inch cable will support 320 tons, or nearly four times
as much as the 6-inch cable, which takes 88 tons.
[Illustration:
_By courtesy of H. Ensor & Sons_
THE SILURUS RAISED, WITH THE PONTOONS, WHICH PROVED OF THE UTMOST
ASSISTANCE, FLOATING NEAR BY]
Few people know that such wonderful ropes exist, but the salvage expert
has full knowledge of where to get them when he requires them, as
he did in the case of the _Silurus_. The ropes were all fixed in place
on the edge of the Gareloch, two batteries of boilers were set up to
supply the power, but before they could be used it was necessary to
arrange a series of signals owing to the fact that the boilers were
out of sight of each other. For one lot to haul faster than the other
would have been fatal. It was absolutely essential that each rope took
its share of the load and that all were hauled on at the same time. As
showing how carefully everything must be considered in so important a
case, the salvors even worked out how much efficiency they would lose
through friction when hauling on the ropes. They left nothing at all to
chance.
Giant wire ropes were lashed round some of the top gear to prevent it
breaking away when the ship came over, a big trench was cut for one set
of ropes to work in, as only by cutting the trench was it possible here
to get a direct pull on the ship, and at last the signal was given to
haul away.
Slowly the _Silurus_ came up, her funnel was tugged from beneath 10
feet of mud. The hauling went on until the pontoons were clear of the
water, until they were no longer a help but a hindrance, so the salvors
cut through the wire lashings with blowpipes and freed them from the
ship. Adjustments were made and the next haul set the _Silurus_ on a
fairly even keel. Despite the strain to which she had been subjected,
the salvor made all his calculations so carefully that she was not in
the least damaged by the operations. Over £56,000 was spent by the
salvor on these operations, but he won his tug-of-war with flying
colours, and the award he received was the reward of sheer merit.
As already mentioned, the divers used hacksaws to cut holes in the
hull under water. In other cases they may bring into play a range of
pneumatic tools--hammers, chisels, and drills worked by compressed air,
which is pumped through a pipe from a boat on the surface. The hammer
and chisel will deliver hundreds of blows a minute, each blow doing an
almost imperceptible amount of work, but the hundreds of blows tell in
the end. An air-driven drill, in spite of the disadvantages of working
under water, will cut a hole an inch in diameter through a plate or
girder an inch thick in one minute.
Frequently, it is desired to remove some submerged rock which
interferes with navigation, and for this purpose pneumatic drills are
often brought into play to make the holes for the charges of dynamite.
The diver proceeds by drilling a series of holes, inserting his
cartridges, after which he stops up the top of the hole with a special
stopping in order to drive the force of the explosion downward. Then he
withdraws to the surface and the boat removes to a distance before the
dynamite is exploded.
Sometimes, however, when it is desired to deepen a rocky channel, a
powerful rock-cutter weighing several tons is brought into play. This
tool is shaped like a pencil and the nose is fitted with a specially
hardened cutter. It is raised to a height and allowed to drop upon the
rock, which it gradually pulverizes and breaks up, the rock-dredger
coming along and completing the work.
Another method followed in the deepening of the channel of the Clyde
was to use diamond drills for boring the holes for the explosives.
The famous Enderslie Rock which caused all the trouble was revealed
one day about the middle of the nineteenth century through the keel
of a steamer coming into contact with it. Up till that time nobody
knew of its existence, but when this steamer damaged herself the
authorities started investigations. They found a bed of rock just over
900 feet long by 320 feet wide, which menaced the bigger ships that
were beginning to navigate the river. The only way of making shipping
safe was to deepen the channel by removing the rock. Accordingly it
was attacked by men working in a diving bell who began blasting it
away with gunpowder. By 1869, after working on it for five years and
spending £16,000, half the channel was deepened to 14 feet, the other
half remaining at 8 feet.
Eleven years later the rock was again attacked, this time by diamond
drills worked by steam-engines. Five years of continuous work saw
the rock removed to a depth of 20 feet over the whole channel. This
improvement, which entailed the blasting away of over 100,000 tons
of rock, cost £70,000, so the Enderslie Rock, upon which the Clyde
authorities spent in all a sum of £86,000, proved rather an expensive
obstruction to find in the river. But it was no mean feat to remove it,
as was done, without in any way interfering with the traffic.