IMPROVEMENTS IN DRAWING, SHIPS OUT OF WATER
Year: 1854

page_text: LETTERS PATENT to. John Lawson, of Glasgow, in the County of Lanark,
North Britain, Engineer, for the Invention of "IMPROVEMENTS IN DRAWING,
SHIPS OUT OF WATER."-A communication.
PROVISIONAL SPECIFICATION left by the said John Lawson at the Office
of the Commissioners of Patents, with his Petition, on the 10th May
1854.
I,, JOHN. LAWSON, of Glasgow, in the County of Lanark, North Britain,
Engineer, do. hereby declare the nature of the said Invention for "IMPROVE-
MENTS IN DRAWING SHIPS OUT OF WATER" to be as follows:-
This Invention relates to an arrangement of lydrostatic pressure apparatus
to be used as a purchase or mechanical power for facilitating the withdrawal
of ships from the water on an inclined plane. The power for obtaining the
necessary movement is conveniently obtainable from a steam engine, laid
down alongside the ship or purchase way, or by a shaft from any other prime
mover, or the hydrostatic press pumps may be worked by hand. The con-
trivance is specially applicable to the general purchase arrangement, for which
Mr William Melville has obtained a grant of British Letters Patent, dated
the Twentieth day of October, One thousand eight hundred and fifty-three,
instead of the duplex screw arrangement, detailed in the Specification filed.
under that Patent. But it is. also generally applicable to other systems of
ships and purchase gear. As adapted to M Melville's plan, two hydrostatic

page_text: presses are laid down in the same longitudinal line and in the line of the
hauling chains of the slip carriage, the stroke of each of the presses being
exactly equal to the length of each. link in the chain, or the distance in the
chain comprehended between the contiguous working catches. Either the
pressure plungers or their cylinders may be made the moving working portion,
the plungers or their cylinders being attached to the hauling side rods, as the
case may be. A convenient arrangement is effected by making the pressure
cylinders fixtures, one before the other in the line of traction with the plungers
or rams attached to the hauling rods; these rods being passed right through
the cylinders longitudinally; then, by working the usual pressure pumps,
the large rams or plungers are made to traverse alternately and. draw up the
slip carriage. One pressure cylinder empties the waste water whilst the
other fills with the actual pressing fluid, and in this way each pressing
traverse takes up the carriage a distance equal to the length of a chain link,
the traverse of the slip carriage being. thus made continuous or nearly so by
a continuous series of engaging and disengaging actions. Instead of this
arrangement of the pressure cylinders and connections, the rams or plungers
may be attached to the hauling chains by cross heads and external side rods.
By another plan, the pressure cylinders may be disposed parallel to each other,
side by side, with external-cross heads and catch apparatus, so as to work the
slip carriage with a continuous movement; or further, the presses may be laid
down in two pairs, one pair before the other; and-the-hauling links running
between them down the centre. At the centre of the slip a four-way rail is
laid down, with two lines of ratchet or inclined stop teeth. As the hauling
chains are drawn up, they are wound upon a laterally traversing drum or
rotatory carrier, as described under the Patent granted to Mr Melville.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said John Lawson in the Great Seal Patent Office on the
9th November 1854.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
LAWSON, of Glasgow, in the County of Lanark, North Britain, Engineer,-send-
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Tenth day of May, in the year of our Lord One
thousand eight hundred and fifty-four, in the seventeenth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the

page_text: said John Lawson, Her special license that I, the said John Lawson,
my executors, administrators, and assigns, or such others as I, the said
John Lawson, my executors, administrators, or 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 "IMPROVEMENTS IN
DRAWING SHIPS OUT OF WATER," (being a communication from abroad), upon
the condition (amongst others) that I, the said John Lawson, by an instru-
ment in writing under my hand and seal, 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 John Lawson, do hereby declare
the nature of my said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement, reference being had to the accompanying Drawings, and to the
letters and figures marked thereon, that is to say:
The said Invention relates to an arrangement of hydrostatic pressure
apparatus, to be used as a purchase or mechanical power for facilitating the
withdrawal of ships from the water on an inclined plane. The power for
obtaining the necessary movement is conveniently obtainable from a steam
engine laid down alongside the slip or purchase way, or by a shaft from any
other prime mover, or the hydrostatic press pumps may be worked by hand.
The contrivance is specially applicable to the general purchase arrangement,
for which Mr William Melville has obtained a grant of British Letters
Patent, dated the Twentieth day of October, One thousand eight hundred
and fifty-three, instead of the duplex screw arrangement detailed in the
Specification filed under that Patent. But it is also generally applicable to
other systems of slips and purchase gear. As adopted to Mr Melville's plan, two
hydrostatic presses are laid down in the same longitudinal line and in the line
of the hauling chains of the slip carriage, the stroke of each of the presses
being exactly equal to the length of a link or of half a link of the chain, or
to the distance or half the distance comprehended between the contiguous
working catches of the chain. Either the pressure plungers or their cylinders
may be made the moving working portion, the plungers or their cylinders
being attached to the hauling side rods, as the case may be. A convenient
arrangement is effected by making the pressure cylinders fixtures, one before

page_text: the other in the line of traction, with the plungers or rams attached to the
hauling rods, these rods being passed right through the cylinders longitu-
dinally; then, by working the usual pressure pumps, the large rams or
plungers are made to traverse alternately and draw up the slip carriage. One
pressure cylinder empties the waste water whilst the other fills with the actual
pressing fluid, and in this way each pressing traverse or couple of traverses
takes up the carriage a distance equal to the length of a chain link, the
traverse of the slip carriage being thus made continuous or nearly so by
à continuous series of engaging and disengaging actions. Instead of this
arrangement of the pressure cylinders and connections, the rams or plungers
may be attached to the hauling chains by cross heads and external side rods.
By another plan, the pressure cylinders may be disposed parallel to each other,
side by side, with external cross levers and catch apparatus, so as to work the
slip carriage with a continuous movement; or further, the presses may be laid
down in two pairs, one pair before the other, and the hauling links running
between them down the centre. At the centre of the slip a four-way rail-is
laid down with two lines of ratchet or inclined stop teeth. As the hauling
chains are drawn up, they are wound upon a laterally traversing drum or
rotatory carrier, as described under the Patent granted to Mr Melville.
And in order that the said Invention may be properly understood, I shall
now proceed to describe the several explanatory Figures on the two Sheets of
Drawings hereunto attached.
Figure 1, on Sheet 1 of the Drawings, is a side elevation; and Figure 2,
on the same Sheet, is a plan, of one modification of the improved slip purchase,
wherein two hydrostatic cylinders are employed; these cylinders being placed.
in a line, one behind the other.
Figure 1, on Sheet 2 of the Drawings, is a side elevation; and Figure 2,
on the same Sheet, is a plan, of another modification of slip purchase,
wherein the hydrostatic cylinders are placed side by side, three being used,
whereof the central one is equal in capacity to the two side ones combined.
Figures 3 and 4, also on Sheet 2 of the Drawings, are end elevations of the
hydrostatic cylinders, looking on opposite ends; and Figures 5, 6, and 7, on-
the same Sheet, are transverse vertical sections, taken at different points, to
shew the construction of the hauling link details.
In the arrangement represented on Sheet 1 of the Drawings, the two
hydrostatic cylinders A, B, are cast with broad flanges C, by which they are
bolted down in a line, one behind the other, to a massive foundation D,
imbedded in the ground at the head of the slip. The plungers or rams E, F,
of the two cylinders work out at the upper ends of these cylinders. The ram

page_text: E of the lower cylinder A has bolted to.it a cross head G, extending trans-
versely, considerably beyond the sides of the cylinder, and supported by a pair
of wheels at the extremities; these wheels are flanged, and run upon short
rails I, laid down on each side of the cylinder. Just within the supporting
wheels H the cross head G is turned, to receive the eyes of the long connecting
side links J, which pass down to the lower link mechanism, for taking hold of
the main hauling chain. The ram F of the upper cylinder B has also bolted
to it a cross head K, which is likewise supported by wheels L running on
rails M. This cross head K does not extend so far on each side as the cross
head G,-since the connecting side links N, which are fixed to it by joint eyes,
pass down inside the corresponding links J.of the cross head G, the links N in
-fact passing through apertures in the cross head G. The two pairs of links or
traction rods J.and N are each connected to a pair of curved or horse-shoe
holding links O by means of link discs P. The hauling chain Q is formed of
5.flat iron links, in alternate sets of three and four pieces, jointed by transverse
pins R. The lower end of this chain is connected in the usual way to the
slip carriage on the slip incline, the upward line of the chain being in the line
of the hydrostatic cylinders A, B, over which it passes to the screw coiling
drum S. This coiling drum is constructed in a similar manner to the one
described under the Patent granted to Mr Melville, already herein-before
referred to. The connection of the horse-shoe links O with the hauling chain
Q is by means of square shoulders T, formed on the upper ends of each link,
and contrived so that the upper links O may fall over and catch upon the
shoulders at each change, whilst the corresponding lower links O are borne up
5 by springs suitably applied. The link discs P are supported upon small
wheels U, which run upon rails V laid down on each side.
In the modification represented on Sheet 2 of the Drawings, three hydro-
static cylinders A, B, C, are used, these cylinders being cast in a single piece,
and with flanges D, by which the combined mass is bolted down upon a bed
plate E, and upon a solid stone foundation F, imbedded in the ground at the
head of the slip. The piston rod G of the central cylinder A issues at a
suffing box in the lower end of this cylinder, and carries a strong cross head
II upon its outer extremity, the weight of this cross head being borne up by
a pair of wheels I, carried in a suitable framing, and running on rails J
beneath. To the cross head I are fixed two short link rods K, passing to
link piece L, which is supported upon a pair of wheels M, a pair of horse-shoc
links.N being jointed to the link piece L, for holding the main hauling chain
O, the links of which have shoulders formed upon their upper ends for the
purpose. The piston rods P of the outside cylinders B, C, which cylinders

page_text: are each of half the capacity of the central cylinder A, also pass out through
stuffing boxes at the lower ends of the cylinders, and extend on each side to a
pair of link pieces Q, supported upon a species of carriage R, passing under
the link details of the central cylinder A, and running upon a pair of wheels
S. To each of the link pieces Q is jointed a long connecting link T; passing
down to the lower horse-shoe holding links U, which are similar to the links
'N above, and are connected to the links T by a link piece V, supported upon
wheels W. The action of the two modifications of hauling apparatus, repre-
sented in the Drawings, is precisely similar; the hydrostatic cylinders being so
worked, that whilst one pair of hauling links is hauling the chain up the
incline the other pair is descending, to take hold of the next lower link of the
hauling chain for the succeeding lift. In the modification represented on
Sheet 2 of the Drawings, the cylinders A, B, C, all communicate with each
other by a passage X at the upper end, so that the water which is behind the
rising piston or pistons for the time being passes to the back of the descending
piston or pistons, and forces it or them down for a fresh stroke. The passage
X communicates by a pipe Y with a reservoir, not shewn in the Drawings,
into which the water can pass, or from which water can be supplied; if it
is at any time necessary to cause all three pistons to traverse in the same
direction. This reservoir may either be fitted up at a sufficient height, to give
the necessary pressure for carrying the pistons to the other end of the cylin-
ders, or it may consist of a closed vessel, provided with a loaded plunger or
valve, for giving the requisite pressure. It is obvious that similar arrange-
ments may be carried out in the modification of apparatus represented on
Sheet I. of the Drawings. In both modifications it is proposed to adopt self-
acting valves to the hydrostatic cylinders, so as by a self-acting reversing
action to cause the pressure flow to act on the different pistons or rams
alternately, thereby producing a continuous or almost continuous hauling
action upon the main chain, without any necessity for reversing the valve
gearing by an attendant.
In the two modifications represented in the
Drawings, the stroke of the hydrostatic cylinders is made equal to half the
length of a link of the hauling chain, since, during the descent of each pair of
hauling hooks through the distance of half a link of the hauling chain, this
chain is at the same time being hauled up an equal distance by the other
pair of hauling hooks, thus bringing up the succeeding link to meet the
descending hauling hook half way. The links of the chain may be made
of a length equal to the stroke of the bydrostatic cylinders, but in that case
the hauling hooks will only lay hold of each alternate link passing over the
intermediate ones.

page_text: Having now described and particularly ascertained the nature of the said
Invention, and the manner in which the same is or may be used or carried
into effect, I may observe, in conclusion, that I do not confine or restrict myself
to the precise details or arrangements which I have had occasion to describe or
refer to, as many variations may be made therefrom without deviating from
the principles or main features of the Invention; but what I consider to be
novel and original, and therefore.claim as the Invention secured to me by the
herein-before in part recited Letters Patent, is,-
First, the general arrangement and construction of hauling apparatus for
drawing ships out of water, as herein-before described.
Second, the application and use of two or more hydrostatic pressure cylin-
ders for drawing ships out of water, such cylinders or their pistons or rams
being connected to two sets of hauling details or connections, and made to
act on the main hauling chain by means of each set of hauling details or
connections alternately, as herein-before described.
In witness whereof, I, the said John Lawson, have hereunto set my
hand and seal, this Seventh day of November, in the year of our
Lord One thousand eight hundred and fifty-four.
JOHN LAWSON. (L.S.)