A NEW OR IMPROVED LIFTING APPARATUS FOR RAISING SUNKEN SHIPS
Year: 1875

page_text: LETTERS PATENT to Jeremiah Hemsted, of South Shields, in the
County of Durham, for the Invention of "A NEW OR IMPROVED
LIFTING APPARATUS FOR RAISING SUNKEN SHIPS."
Scaled the 9th December 1875, and dated the 9th October 1875.
PROVISIONAL SPECIFICATION left by the said Jeremiah Hemsted
at the Office of the Commissioners of Patents, with his Petition,
on the 9th October 1875.
I, JEREMIAH HEMSTED, of South Shields, in the County of Durham,
do hereby declare the nature of the said Invention for "A NEW OR
IMPROVED LIFTING APPARATUS FOR RAISING SUNKEN SHIPS," to be as
follows:-
My Invention has for its object the raising of sunken ships, for which
purpose I provide two large cylinders, both divided horizontally into
three air-tight compartments with suitable valves, and so constructed
with egg-shaped fore end and a stern post for the rudder as to ride
safely at sea under the control of a man, by whom it is steered while
being towed to its destination by a steamer.

page_text: Prior to the arrival of the cylinders, or before they are brought into
use, divers have descended and placed in every available part of the
submerged ship a number of collapsable air-tight chambers. These can
easily be taken into the hold or between the decks of the ship and the
under side made fast by rings to ring bolts in the deck of the locality in
which they are placed. They are then pumped full of air, causing them
to expand and drive the water out of the ship's cabins and hold, or
from any part they may be put in, thus rendering the sunken ship
lighter and more readily raised by the two cylinders which are now sunk
one on each side of the ship by opening a valve or valves which admits
water into the compartments at pleasure.
Several strong chains having previously been placed under the keel,
and where that is impossible through the port holes of the ship, are
fastened to cyes formed in a strong rib or ridge running along the side
of cach cylinder and now lying in close proximity to the ends of tho
chains.
When the chains are fastened to the ribs of the two cylinders, and
between them the sunken ship having the air-tight collapsable chambers
expanded within, and the several chains under her keel, the cylinders
are then pumped sufficiently full of air as to, with the assistance of the
aforesaid air chambers, bring the vessel to the surface, when they are
towed to a place of safety.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Jeremiah Hemsted in the Great Seal Patent
Office on the 17th March 1876.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JEREMIAH
HEMSTED, of South Shields, in the County of Durham, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Ninth day of October, in the year
of our Lord One thousand eight hundred and seventy-five, in the
thirty-ninth year of Her reign, did, for Herself, Her heirs and suc-
cessors, give and grant unto me, the said Jeremiah Hemsted, Her
Special licence that I, the said Jeremiah Hemsted, my executors,

page_text: administrators, and assigns, or such others as I, the said Jeremiah
Hemsted, my executors, administrators, and assigns, should at any time
agree with, and no others, from time to time and at all times thereafter
during the term therein expressed, should and lawfully might make,
use, exercise, and vend, within the United Kingdom of Great Britain
and Ireland, the Channel Islands, and Isle of Man, an Invention for
"A NEW OR IMPROVED LIFTING APPARATUS FOR RAISING SUNKEN SHIPя,” upon
the condition (amongst others) that I, the said Jeremiah Hemsted,
my executors or administrators, by an instrument in writing under
my, or their, or one of their hands and seals, should particularly
describe and ascertain the nature of the said Invention, and in what
manner the same was to be performed, and cause the same to be
filed in the Great Seal Patent Office within six calendar months next
and immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Jeremiah Hemsted, do hereby
declaro the nature of my said Invention, and in what manner the
same is to be performed, to be particularly described and ascertained
in and by the following statement in writing, that is to say:―
My new or improved apparatus for raising sunken vessels consists
mainly of two cylinders peculiarly constructed, as will be herein-after
fully described. They are sunk one on each side of the submerged
vessel, to the fore and after parts of which they are attached by hawsers
passing from ring bolts on the upper part of the cylinders through
hawser holes in the vessel, and therein made fast. These cables are not
for the purpose of raising the ship, but rather to prevent the cylinders
shifting their position either from the influence of a current or from
the unequal strain brought to bear on them when in the act of raising
the vessel. These cylinders are fastened together by a number of chains
proceeding from a ridge running longitudinally along the under side of
one cylinder and passing under the keel of the ship to a similar ridge on
the other. It is by these chains, in conjunction with a chain surround-
ing the wreck and shackled to the said ridges, that the vessel is raised
when the cylinders are made sufficiently buoyant to bring it to the
surface, as will be herein-after more fully explained.
As an adjunct to these cylinders, and to lighten the vessel as much as
possible, I provide a number of collapsable air-tight chambers or bags
which are placed in every available part of the ship in a collapsed

page_text: condition. Each air-tight chamber is surrounded by a strong netting
having a cable running along the under side, to which is fastened
several rings for the purpose of shackling it down to ring bolts screwed
in the timbers or under deck of the vessel.
I will now proceed to describe my Invention more fully in detail by
aid of the accompanying Drawing, reference being had to the letters
and figures marked thereon.
Figure 1 is a cross section on line A, B, (Figs. 3 and 4), of a cylinder,
shewing the manner in which I divide the interior into compartments
and the means employed to fill or empty them of water to gain the
desired result.
Figure 2 is a stern view, shewing the cocks or valves for drawing out
or admitting water at that end when required. The stern of the
cylinder is similarly fitted with cocks, as may be seen in Figure 3,
which is a part longitudinal elevation of the same cylinder, shewing
the method of attaching the lifting chains thereto and the positions of
the air cocks communicating with the aforesaid compartments. Means
are also shewn in this Figure to adapt the cylinder for navigation either
by sails or towage.
Figure 4 shows a general plan of my arrangement when brought into
operation, the vessel to be raised lying between the two cylinders with
the lifting chains under her keel. This view also shews more clearly
the positions of the air-cocks.
Figure 5 is an end view, shewing one cylinder sunk in position ready
for operation. The other is being sunk and guided to its place by a
rope or ropes attached to a mushroom anchor and carried up to the tug
boat, where the descent of the cylinder is controlled by the flexible
tubes leading from the air-cocks, as shewn.
Figure 6 is a longitudinal section and Figure 7 a cross section of a
sunken ship, loaded in ballast only, to show the position of the air-tight
chambers or bags.
In all these Figures A, C, are the two cylinders, each divided into
five compartments 1, 2, 3, 4, and 5, as shewn in Figure 1. These
compartments are air-tight, and do not communicate with one another
except by a man-hole that may be made air-tight after having been used
during construction or repairs. The upper compartment 1 is of

page_text: sufficient capacity to carry the cylinder with all her stores and gear
when proceeding to its destination; the lower divisions 4 and 5 being
full of water, act as ballast, and render the cylinder seaworthy.
Each compartment is provided with three valves or cocks. Those
belonging to compartment 1 may be more plainly seen in Figure 3, and
are numbered I., II., and III. The first and last (I., III.) are placed at
the lowermost part of the compartment, and are for the passage of
water. The second (II.) is fixed at the highest part for the entrance or
exit of air.
The air-cocks (V., VIII., XI., and XIV., see Figure 4) of the other
compartments are necessarily connected to their several chambers by
air-tubes b, c, d, and e, as shewn in Figure 1.
As before observed the cylinders are rendered navigable and provided
with a stern E and stern post F, with a rudder that can be unshipped
when the apparatus is to be sunk (see Figure 3). The forecastle H is for
the storage of the sails, ropes, and gear when not in use. The cabin I
and the gangway K for the accommodation and protection of the men
when at sea. The life-boat L at the stern conveys the men to and from
the cylinder, or should a storm arise and the apparatus become by any
means unmanageable, recourse can be had to this boat for safety, the
cylinder or cylinders being afterwards sunk and the place marked by a
buoy to enable them to be easily found and recovered at a suitable
time.
On the upper sides of the apparatus are fixed several ring bolts R, R,
to which the stays of the mast when rigged may be secured. They are
also particularly useful to guide the cylinder during its descent, as
shewn in Figure 5, where C is the cylinder, S the cable fastened to a
mushroom anchor placed in a suitable position with regard to the
ship B. The cable ascends from the anchor, and after passing through
one of the ring bolts it is made fast to the tug boat. There may be two
or more such cables used, according to the requirements of circum-
stances. The descent of the cylinder is controlled on board the tug by
the air-cocks having flexible tubes screwed thereon, and terminating on
board the aforesaid tug with valves or cocks, or other suitable means, by
which full control may be had on the exit of or forcing in atmospheric
air in order that the apparatus may not suffer damage by striking
heavily against the bottom when it has arrived at the full depth.

page_text: Along the under side (and on each side of the cylinder in order to
allow it to be sunk on either side of the wreck) runs a strong ridge
M, M, Figures 2 and 3, having holes or eyes at frequent intervals for the
attachment of the chains t, t, that are placed under the keel of the
vessel, as shewn in Figures 4, 5, and 7. Nearcr the bottom, and
parallel with the before-mentioned ridge, is a stay or support N, N, to
the apparatus to prevent the cylinder rolling over when resting on its
bed. At. the extremities of this support are one or two holes for the
purpose of lashing a similar or smaller apparatus to the first when
additional power is required.
The mode of operation is as follows :-Should the weather bo
boisterous the two cylinders are cach tugged to the wreck by a tug
boat, but when the weather permits jury masts are rigged, and the tugs
precede the cylinders in order to make, by means of divers, a survey of
the wreck. The divers also place in the hold of the vessel (when the
ship is light or only loaded in ballast) and indeed in every available
space the before mentioned air-tight chambers or bags which are taken
down in a collapsed condition and shackled to ring bolts in any con-
venient place. This prevents the said chambers or bags shifting their
position when air is forced therein by means of an air-pump (on board
the tug boat) to which they are connected by long flexible tubes
screwed on the union cocks a, a, Figure 6. On becoming inflated they
expel a portion of the water from the interior of the ship, and rising,
take a bearing against the under side of the deck, as shewn in Figures 6
and 7. The union cocks are then shut and the flexible tubes unscrewed
to be used again when required for the cylinders, as hercin-after
explained. The divers then proceed to pass chains, where practicable,
under the keel of the vessel, ready to be attached to the cylinders when
placed in position. Mushroom anchors are now suitably fixed alongside
the wreck, with guide ropes leading therefrom to the tug boat wherein
they are made fast.
The cylinders having now arrived the masts are dismantled, the
rudder unshipped, and everything removable transferred to the tug boat.
Long flexible tubes of sufficient length and strength are then screwed
on the air-cocks II., V., VIII., XI., and XIV. (see Figure 4), and the
guide ropes passed through the ring bolts R, R, when all being ready
for lowering the cylinder the diver opens all the cocks, admitting water
into the compartments; but the extremities of the flexible tubes being

page_text: also fitted with cocks which are closed and under the control of the
workmen will not allow sufficient water to enter until the air is
permitted to escape by opening the said cocks, which being done only
sufficient water is admitted to sink the apparatus.
During the descent of the cylinder it may be desirable to retard its
downward progress. In that case the tube connected to chamber 1 is
placed in union with an air pump, and by means thereof a portion of
the water is driven out of the compartment to lighten it and thus
prevent the cylinder reaching the bottom with undue velocity.
The cylinder having reached the bottom the chains t, t, (see Figures
3, 4, and 5) previously passed under the vessel's keel are now shackled
by the divers to the ridge M, Figures 1, 2, and 3. This is quickly donc,
onc or other of the numerous eyes or holes along the ridge presenting
themselves to every chain. Should the cylinder alight in such a
position as to render difficult or impossible the shackling of the chains
to the said ridge, the air tube leading to the compartment 4 or 5, as the
occasion may require, is applied to the air pump and air forced in,
driving out the water and turning the cylinder sufficiently to bring the
ridge into a suitable position.
The cylinder having been shackled to the several chains, hawsers are
brought from the hawser holes fore and aft of the ship and made fast to
any of the ring bolts R, R, sec Figure 4, in order to prevent shifting,
as before mentioned.
While the divers have been thus engaged the second cylinder, which
is a duplicate of the above, has been lowered in like manner to the first,
and after being similarly shackled to the chains t, t, and made fast to
the vessel by hawsers, as before explained, the bridle chains u, u*, are
then brought round the ship fore and aft and secured to any convenient
part of the ridge of each cylinder. The wreck is now supported in a
kind of cradle, and the apparatus may be set into working order by
connecting to all the water cocks (see Figure 4), similar flexible tubes
to those before described for the air-cocks.
On board each tug boat is the necessary machinery for forcing air
into, or drawing water out of, the two cylinders to render them
sufficiently buoyant to lift their burden, and as the orifices of the tubes
belonging to each cylinder are under the control of those on board, the

page_text: water can either be forced by air pumps out of, or withdrawn from, cach
compartment separately or conjointly. The ascent of the apparatus,
and with it the ship, being regulated if required in a manner reverse of
that described for regulating the descent of the cylinder.
On regaining the surface all the valves or cocks are shut and the
flexible tubes disconnected. The rudders are re-shipped, a tow line is
made fast to any suitable place, and the apparatus, with the wreck
supported, towed by the tug boats to a place of safety. Should the
weather be favorable the masts may be rigged to assist the tug boats in
transporting the burden.
In the event of a vessel foundering on a rocky bed, or where the
apparatus could not be placed in position as above stated, the cylinders
should then be sunk to a convenient depth and made fast to the cables
used as guide ropes until the lifting chains are secured from cylinder to
cylinder. That being done the whole might then be raised in a manner
and by the means before mentioned.
Having now described the nature of my said Invention, and in what
manner the same is to be or may be carried into effect, I claim without
limiting myself to these precise details, the method and means of
raising sunken vessels, substantially in manner as hercin more fully
set forth and specified and illustrated on the accompanying Drawing.
In witness whereof, I, the said Jeremiah Hemsted, have hereunto
set my hand and scal, this Fourteenth day of March, in the
year of our Lord One thousand cight hundred and seventy-
six.