AN IMPROVED METHOD OF AND MEANS EMPLOYED FOR RAISING SUNKEN VESSELS OR OTHER SUBMERGED OBJECTS
Year: 1877

page_text: PROVISIONAL SPECIFICATION left by Thomas Archer, junior, at the Office of
the Commissioners of Patents on the 20th April 1877.
THOMAS ARCHER, junior, of Dunston, in the County of Durham, Engineer. "AN
IMPROVED METHOD OF AND MEANS EMPLOYED FOR RAISING SUNKEN VESSELS OR
OTHER SUBMERGED OBJECTS."
In raising sunken vessels or other submerged objects by the aid alone of buoyant
bodies, as air casks or pontoons, it has been found that upon attaching a sufficient
number of these bodies to the submerged vessel the latter ascends with undue
velocity, and on arriving at the surface with an accelerated speed, springs from the
water or to a height beyond its floating capacity, and before it recovers its proper
medium or position of repose it has thrown so great a strain and other disturbing
forces upon the attachments of the lifting apparatus, and upon the structure of the
vessel, as to endanger the stability of both and the risk of the vessel again sinking
and breaking up consequent upon the derangement of the pontoons. To remedy
this evil, and to produce a controllable and uniform upward motion of the sub-
merged vessel, is the first part of my Invention, which is thus effected :-Over and
on each side of the object to be raised, say a sunken ship, two suitable hulls aro
moored, each being provided on both sides with two or more loose pulleys projecting
over and supported by the bulwark or side of the hull; an equal number of wire
ropes are made fast to the two sides of the vessel to be raised, and after passing
upward to the surface each rope is made to cross one of the hulls and over the
before-mentioned pulleys. The free end of each rope terminate in a suitable weight
hanging at or near the surface of the water. These weights I call regulators, as
they regulate or control in a manner herein-after explained the speed of the
ascending vessel when the same is made sufficiently buoyant by attaching a number
of air casks or pontoons.
The usual method of sinking these pontoons is by admitting water therein
through suitable valves to render the said pontoons slightly heavier than the water
in which they are required to be sunk. This operation necessitates the subsequent
employment of an air pump, with its concomitant evils; to dispense with the use of
such air pump and the fitting of valves in the pontoon is the second part of my
Invention, which I carry out in the following manner-I make each pontoon air
tight and without valves of any kind. To sink them into position they are loaded
with a suitable weight or weights, and lowered from a jib or crane carried in any suit-

page_text: able boat from which the operation of lowering and fixing these pontoons is carried on.
The pontoon being sunk and suitably attached to the submerged vessel, it is detached
from the chain by which it was suspended, and the said chain drawn up, carrying
with it to the surface the sinking weights, leaving the pontoon to exert its lifting
power.
When a sufficient number of these pontoons have been added and suitably dis-
tributed around and within the sunken vessel, the weights or regulators before
mentioned now begin to exert their preponderance over the difference between the
floatation power of the pontoons and the weight of the submerged vessel, starting
the same from its bed. The said vessel being once set in motion less force or power
is required to continue the same; this contingency may be met by the regulators
entering and descending through the water, which reduces their weight, but should,
however, this reduction prove too great, the proper amount can be afterwards
added by attaching suitable weights to the descending portion of each wire rope.
The third part of my Invention relates to the means employed for getting a
chain or wire rope, or a number of them, under the keel of a vessel that may be
sunk on a muddy or sandy bottom, as in the case of H.M.S. "Vanguard."
The apparatus I employ to effect this purpose consists of a long needle having a
recess or mouth formed at any suitable distance from its point for receiving the
middle or waist of a steel wire rope, which may be prevented from falling out by
passing a linch pin through the two lips of the recess and in front of the said rope;
or the direction of the said mouth may, instead of being horizontal, take a direction
from below upward. From the head of this needle extends an eye bolt for the
attachment of a chain proceeding from a jib or crane for lowering the said needle when
about to be brought into operation. On reaching the bottom the point of this needle
should penetrate the mud or sand near the bows of the embedded vessel, carrying
the wire rope with it to a depth consistent with the weight of the needle and the
density of the mud or sand through which the needle and rope pass. Should
however extra pressure be required to drive the said needle to a sufficient depth
weights may be placed by divers on to the head of the aforesaid needle, the eye bolt
preventing them, in a manner so well understood, from falling off. When the needle
has carried the wire rope a sufficient depth below the keel of the embedded vessel,
the two ends of the said rope being above the surface of the water, are each secured
to a tug boat. The tug boats, by an alternate progressive and retrogressive motion,
that is to say, a sawing motion, draw or drag the wire rope under the vessel's keel,
which being effected any number may follow by the same means; or the first named
rope may, on arriving at a certain point along the vessel's keel, have another but
shorter rope attached to it at or near the surface of the sand, so that when the tug
boat on the opposite side of the submerged vessel to that on which the attachment
is made takes a course at right angles to the keel of the said ship it shall drag the
short rope transversely under the aforesaid ship; the short rope may then be
detached and left under the vessel with its two ends buoyed up above the sand,
line. This operation may be repeated until a sufficient number of wire ropes or
cables are arranged under the vessel's keel, to which air casks or pontoons may be
attached as before explained.
The before-mentioned regulators would regulate or control the ascent of the sub-
merged vessel in the following manner:-The last air cask or pontoon having been
attached to the submerged vessel, the regulators being previously placed in position
and exerting their gravitating power, the vessel commences to ascend with an
accelerated motion, but as the buoyant power of the pontoons is not sufficient to
raise the said vessel, the upward tendency of the same must be due to the descent
of the gravitating weights, which may be regulated or controlled by the application
of a brake in any suitable manner.