IMPROVEMENTS IN THE CONSTRUCTION OF SHIPS AND RAFTS
Year: 1859

page_text: LETTERS PATENT to Thomas Symes Prideaux, of Willow House, Hamp-
stead, and 32, Charing Cross, Civil Engineer, for the Invention of
"IMPROVEMENTS IN THE CONSTRUCTION OF SHIPS AND RAFTS."
PROVISIONAL SPECIFICATION left by the said Thomas Symes Prideaux
at the Office of the Commissioners of Patents, with his l'etition, on
the 21st October 1859.
I, THOMAS SYMFS PRIDEAUX, of Willow House, Hampstead, and 32,
Charing Cross, Civil Engineer, do hereby declare the nature of the Invention
for IMPROVEMENTS IN THE CONSTRUCTION SHIPS AND RAFTS," to be as
follows:-
This Invention has for its object to accelerate the speed and increase the
strength and stability of ships by improving the form of the hull, making
it shot proof, lightening the weight of the masts and spars, and employing
the ejection of water or a submerged paddle wheel at the middle or fore
part in combination with a propeller at the stern as a means of propulsion;
also to provide them with portable rafts, easily put together and capable of
being advantageously substituted (for many services) for a portion of the
boats at present carried, the space for which will be curtailed by the
shortening of the upper deck.
It appears to me that in the construction of ships hitherto the great
[Price 8d.1

page_text: importance of enabling then to hold a steady course in a right line has not
been sufficiently considered. By this I do not mean that the disadvantage of
a crooked course has been overlooked, what I mean is that the evil of
small perturbations in the axis of a ship's course, each one of which must
change the line of direction of the momentum, and exercise an injurious
influence on the speed, has not been sufficiently recognised, more especially
since the extensive adoption of steam and disuse of sails has, by diminishing
steadiness, so greatly increased the amount of the evil.
To promote the motion of a ship through the water in a right line, it is
desirable that the shape of the bow be such as so to divide the force of resist-
ance of the water opposing its passage as to cause it to deflect the bow from
the axis of motion equally in all directions, that thus the pressure on every
side being balanced there may be no influence exerted on the bow tending to
divert the ship from her true course. This object is to be obtained by making
the bow conical, with the point of the cone about 6 or from 7 to 5 of her
depth of immersion (not including the keel) from the surface. This conical
form of bow has also another advantage, vizt., that the angle which divides
the water is more acute. Thus, if at any given distance behind the bow the
draught of water is equal to this distance, it is clear that the chord of the arc
of the stem post ise hypothenuse of a right angled triangle, the height and
base of which are equal, and consequently presents to the water an angle
of 45°, whereas supposing such a bow to be conical, the mean of the two
angles would be 22°.
In the present form of bow the resistance of the water when the vessel is
in motion lifts her fore part above the line of floatation it would occupy when
at rest, causing more or less oscillation or pitching as her motion is accelerated
or retarded, the injurious influence of which on speed I have repeatedly seen
strikingly exemplified in the detrimental effect of even a very slight swell on
the performance of a steam vessel with full bows; and on each side, behind
the conical bow, I construct chambers, to which the water is admitted
from the exterior, and forcibly ejected at the bottom or sides backwards in
a line with the keel, thus acting, in combination with the stern propeller, to
accelerate the speed of the ship. This most important point, particularly
for purposes of war, the steadiness of ships, may be still further increased
by the addition of plane surfaces attached to their sides at about the level
of the point of the (cone) bow, forming lateral fins, and also by diminishing
the weight aloft, to do which, without lessening the strength of the masts
and spars, I substitute corrugated iron or steel tubes in place of the wooden
or common sheet iron masts and spars in use at present.

page_text: To secure the sides of vessels from shot, by means of plating them with
iron, three principles must be attended to:-First, to prevent the destruction of
the plate by molecular vibration, which must be checked by the plates being
muffled in the same way as we muffle a bell; secondly, the force of the blow
should be received and spread over as large an area as practicable; thirdly, it
should be prolonged throughout as great a space of time as possible. To
effect these objects, I surround the plates of iron or steel with a hempeu
sacking or some substance equivalent in its effect in destroying sonorous
vibrations, with an additional cushion stuffed with wool, horsehair, steel wire,
or any other suitable elastic material on the front side, which cushions may be
encased in thin copper sheathing, to prevent their imbibing water. Lastly,
the plate is affixed to the vessel's side by bars of steel, forming powerful
springs; or, I use compound plates, formed of a number of small plates or
bars arranged edgeways or side by side, with a layer of hemp, wool, hair,
cork, or any equivalent elastic material between each, pinned together and
fastened into a frame, so as to form one block.
In constructing portable rafts, I keep three objects in view as equally
important. First, portability with regard to smallness of space into which
they may be packed; secondly, portability as regards lightness of weight;
third, facility of being put together in a short time. To obtain these three
objects to the greatest possible extent, I employ in the construction of these
rafts a light framework of wrought iron or steel, capable of being quickly
screwed and braced together, and forming, so to speak, the skeleton of the
raft. Within this framework, and surrounded and protected by it, I place
a double tier of caissons or vessels, to give the requisite power of floatation.
These caissons may be made of thin sheet metal, with diaphragms soldered
in the interior, dividing each into 2, 3, 4, or more, if thought desirable, air-
tight chambers, or, where it is required to stow away the portions of the
raft in still smaller space, the caissons may be constructed of water-proof
cloth, and fitted with stop-cocks, so as to admit of being emptied, and refilled
with air at pleasure, and will thus be capable, when not inflated, of being
rolled up and stowed away in a very small compass. For the framework of
the raft, I prefer to employ corrugated iron or steel tubes, as combining the
greatest lightness with the greatest strength, but angle iron, or any other light
form of iron girder may be substituted.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Thomas Symes Prideaux in the Great Seal Patent Office
on the 21st April 1860.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, THOMAS
SYMES PRIDEAUX, of Willow House, Hampstead, and 32, Charing Cross, Civil
Enginer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-first day of October, in the year of our
Lord One thousand eight hundred and fifty-nine, in the twenty-third year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said Thomas Symes Prideaux, Her special licence that I, the said
Thomas Syines Prideaux, my executors, administrators, and assigns, or such
others as I, the said Thomas Symes Prideaux, 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 Inven-
tion for "IMPROVEMENTS IN THE CONSTRUCTION OF SHIPS AND RAFTS," upon the
condition (amongst others) that I, the said Thomas Symes Prideaux, 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 Thomas Symes Prideaux, do hereby
declare the nature of the said Invention, and in what manner the same is to
be performed, to be particularly described and ascertained in and by the
following statement thereof, that is to say:-
This Invention has for its object to accelerate the speed, and increase the
strength and stability of ships, by improving the form of the hull, making it
shot proof, lightening the weight of the masts and spars, and employing the
ejection of water or a submerged paddle wheel at the middle or fore part. in
combination with a propeller at the steam as a means of propulsion, also to
provide them with portable rafts easily put together and capable of being
advantageously substituted (for many services) for a portion of the boats at
present carried, the space for which will be curtailed by the shortening of the
upper deck.

page_text: It appears to me that in the construction of ships hitherto, the great
importance of enabling them to hold a steady course in a right line has not
been sufficiently considered. By this I do not mean that the disadvantage of
a crooked course has been overlooked; what I mean is that the evil of small
perterbations in the axis of a ship's course, each one of which must change the
line of direction of the momentum and exercise an injurious influence on the
speed, has not been sufficiently recognised, 'more especially since the extensive
adoption of steam and disuse of sails has, by diminishing steadiness,so greatly
increased the amount of the evil.
To promote the motion of a ship through the water in a right line, it is
desirable that the shape of the bow be such as so to divide the force of
resistance of the water opposing its passage as to cause it to deflect the bow
from the axis of motion equally in all directions that thus the pressure on every
side being balanced, there may be no influence exerted on the bow tending to
divert the ship from her true course. This object is to be obtained by making
the bow conical, with the point of the cone about 6, or from 7 to 5 of her
depth of immersion (not including the keel) from the surface. This conical
form of bow has also another advantage; vizt., that the angle which divides
the water is more acute. Thus, if at any given distance behind the bow the
draught of water is equal to this distance, it is clear that the chord of the arc
of the stem post is the hypothenuse of a right angled triangle, the height and
base of which are equal, and consequently presents to the water an angle
of 45°, whereas, supposing such a bow to be conical, the mean of the two
angles would be 221°.
In the present form of bow the resistance of the water, when the vessel is in
motion,lifts her fore part above the line offloatation it would occupy whenatrest,
causing moreorlessoscillationorpitchingashermotionisacceleratedorretarded,
the injurious influence of which on speed I have repeatedly seen strikingly ex-
emplified, in the detrimental effect of even averyslightswellon theperformance
ofasteamvessel with fullbows. And on each side, behind the conical bow, I con-
struct chambers, to which the water is admitted from the exterior, and forcibly
ejected at the bottom or sides backwards in a line with the keel, thus acting in
combination with the stern propeller to accelerate the speed of the ship. This
most important point, particularly for purposes of war, the steadiness of ships,
may be still further increased by the addition of plane surfaces attached to
their sides at about the level of the point of the (cone) bow, forming lateral
fins, and also by diminishing the weight aloft; to do which without lessening
the strength of the masts and spars, I substitute corrugated iron or steel

page_text: tubes in place of the wooden or common sheet iron inasts and spars in use at
present.
Figure 1 is a side view, Figure 2 a plan, and Figure 3 an end view of a
ship constructed in the manner above described; it is built, by preference, of
iron, and, as will be seen, made of a conical form both fore and aft. The keel
which is of considerable depth at midships, increases in depth as it approaches
the bow and stern. The ship is also furnished with plain surfaces, one
running horizontal along each side, and from end to end thereof, and with
others of greater depth attached to the conical ends of the ship, from which
they stand vertically, as is shown. The keel and the plane surfaces above
mentioned are formed of stiff frames, strongly secured to the framing of the
vessel, and plated exteriorly in the same manner as this framing. The plane
surfaces above mentioned check both the rolling and pitching of the ship, and
also any deviation of the same from a straight line when propelled either by
steam, sails, or other motive power. The centré portion of the vessel between
the two conical ends is decked over, and may be raised, if desired, to a
sufficient height to carry two decks, one over the other, if desired, and if the
ship is for war purposes, one or both the decks may have guns mounted
thereon.
The ship is propelled by means of submerged paddle wheels; these wheels
work in cases open only at the bottom, and the rotation of the wheels draws
the water into these cases, and ejects it again in a direction opposite to that in
which the vessel is propelled, and these wheels are tobefixedonseparateaxles,
so as to be able to revolve in opposite directions. In addition to these paddle
wheels a screw of ordinary construction may be employed at the stern of the
ship. The Drawing is intended to represent a ship of war of the largest class,
about 50 feet wide and 400 feet long, carrying 52 heavy guns. The peculiar
advant aes of this mode of construction are the power of firing the whole of
the one-fourth towards each of the four opposite points of the compass
guns
simultaneously; greatly increased speed, attained by the shape of the hull,
assisted by the steadiness and direct motion produced by the lateral fins, and
the absence of pitching and scending from the absence of heavy weights from
the extremities; greatly increased stability of gun platform arising from the
same causes, a point of immeasurably greater importance now with the
improved system of gunnery than formerly when vessels could engage for an
hour yard arm to yard arm; greatly increased facility of turning and
manoeuvring from the combinationofthe submergedpaddlewheelswithascrew,
and in particular from the submerged paddle wheels having each its separate

page_text: axle, so as to be capable of being driven in opposite directions; thus, supposing
it be required to turn quickly towards the port side in addition to putting the
helm hard a starboard, the port paddle wheel would be reversed bringing the
vessel round in a minute, and in about twice her own length instead of
describing a circle half a mile in diameter, and occupying ten minutes in the
operation. So inadequate will such a style of manoeuvring be found to meet
the exigencies of modern warfare, that our present steam navy will be as
entirely superseded by ships of the class here described as our old sailing line
of battle ships have been by the introduction of the existing screw steamers.
The masts and spars of the vessel, as before mentioned, are made of corrugated
iron or steel tubes. In making such masts and spars, I first corrugate the
plates to be employed, and then bend them and rivet them up into a tub lar
form, or the tubes may be made first and the corrugations stamped up by
subjecting the tubes to external pressure on a mandril of the requisite form;
the corrugations run from end to end of the mast or spar, and taper to
correspond with the taper of the mast or spar, that is to say, the corrugations
are both higher and wider at the lower part of the mast, where it is largest in
diameter, than they are at its upper end, where the mast is of its smallest
diameter. The form which I prefer to give to the corrugations is clearly
shown by the end view, Figure 4. To obviate an objection to the use
of iron masts, as at present fitted, videlicet, that they cannot readily be
cut away in case of need, I secure such masts in the manner shewn at
Figure 5, where is a wrought-iron frame, forming the foot of the mast,
firmly fixed to the deck of the ship, and having formed on it at a one portion
of a binge joint; the other portion of this joint is attached to the mast at b,
and a pin c holds the two together. Round the lower part of the mast á
flange d is formed, and there is also a flange a² on the casting a.
When the
mast is in its place, its flauge d stands on the flange a² of the frame forming
the foot, and the two are secured the one to the other by the clip e, one end of
which is jointed to the deck, and the other (when the clip is in its place) is
secured to the deck by a pin f. By removing the pin fand turning back the
clip, the masts may be lowered on to the deck, turning about the hinge joint,
ór by also removing the pin c of the joint, the mast may be cast entirely free.
On making the sides of ships shoot proof. When a cannon ball penětratės
any resisting surface it does so by virtue of its force or mechanical effect over-
powering the attraction of coliesion in the particles of the opposing body.
Since the momentum of a ball of a given weight at a given velocity is à
constant quantity, and a ball can only be arrested by its force or mechanical
effect being expended, i.e.; transferred to the resisting medium, it follows that

page_text: the power of any given substance to resist any given ball must be in inverse
ratio to the concentration of the transfer of the mechanical effect of such ball,
or directly as the extent of surface receiving and the length of time occupied
in expending the force. Thus, if the momentum of a cannon ball be only just
sufficient to penetrate an iron plate when the surface of impact is 50 square
inches and the time occupied in expending the force is the 50 of a second, it
is evident that either increasing the surface of impact to 100 inches, or
increasing the time in which the effect is absorbed to the of a second
would effectually preserve the plate from disintregration, whilst the employ-
ment of both expedients conjointly would arrest the passage of a shot of double
the momentum. The greater the amount of matter amongst which a shock is
distributed the less falls to the share of the individual atoms, and the less the
likelihood of the attraction of cohesion between any being ruptured; whilst
the longer the time occupied in transferring a given mechanical effect, the
smaller will be the proportion which the force acting at any given instant will
bear to the whole force arrested. It is then upon the judicious application of
these two principles, viz., the increase of the particles of matter which receive
the shock and the prolongation of the time during which the shock is being
transferred that the success of all efforts to make materials of moderate
thickness shot proof must depend. To secure the sides of vessels from shot by
means of plating them with iron I surround the plates of iron or steel with a
hempen sacking, or some substance equivalent in its effect in preventing
molecular vibrations, with an additional cushion stuffed with wool, horsehair
steel wire, or any other suitable elastic material on the front side, which
cushions may be encased in their copper sheathing to prevent their imbibing
water. Lastly, the plate is affixed to the vessel's side by bars of steel, forming
powerful springs.
Figure 6 is a side view, and Figure 7 is a horizontal section of a portion of
a ship's side protected in the manner above described. u, a, are steel springs
attached to the side of the ship by studs ; from each stud four springs
radiate, and at their outer ends they pass through loops or eyes formed at the
four corners of the iron blocks c, c; d d, are packings of fibrous or other
suitable material secured to the blocks c; these packings d, d, in order to prevent
the sea breaking over them and saturating them with water are coated with
a thin and flexible skin of copper e, reaching down to the water line.
It will be obvious that when a shot strikes one of the protecting blocks it
will either entirely or in great part expend its force on the packing d and
these springs a the suddenness of the blow will be increased, and the blow
will be spread over a larger area of the side of the ship.

page_text: In place of the arrangement above described, I sometimes use compound
plates formed of a number of small plates or bars arranged edgeways or side
by side, with a layer of hemp, wool, hair, cork, or any equivalent elastic
material between each, pinned together and fastened into a frame so as to
form one block.
Figure 8 is a vertical section of a portion of the side of a ship, to which such.
protecting blocks are attached. Figure 9 is a front view of one of the blocks
with its springs; a, a, are springs attached, each at one end to the ship's side,
and at their other ends passing through loops or eyes formed on the blocks,as is
shewu. b, b, are wrought iron cases forming the framings of the blocks, and
c,c,are bars of wrought-iron or steel packed in such cases, and having a pad-
ding of fibrous or other suitable material d all around them. e, e, are pins
which keep the bars c, c, in their places; fis a thin skin of metal to prevent
the packing d becoming saturated with water. The action of the apparatus
will be similar to that in which solid iron or steel blocks are employed.
In constructing portable rafts, I keep three objects in view as equally
important. First, portability with regard to smallness of space, into which
they may be packed; secondly, portability as regards lightness of weight;
third, facility of being put together in a short time. To obtain these three
objects to the greatest possible extent, I employ in the construction of these
rafts a light framework of wrought iron or steel, capable of being quickly
screwed and braced together, and forming, so to speak, the skeleton of the
raft. Within this framework, and surrounded and protected by it, I place a
double tier of caissons or vessels to give the requisite power of flotation. These
caissons may be made of thin sheet metal, with diaphragms soldered in the
interior, dividing each into 2, 3, 4, or more, if thought desirable, air-tight
chambers; or where it is required to stow away the portions of the raft in
still smaller space, the caissons may be constructed of waterproof cloth, and
fitted with stop-cocks so as to admit of being emptied and refilled with air at
pleasure, and will thus be capable when not inflated of being rolled up and
stowed away in a very small compass. For the framework of the raft I prefer
to employ corrugated iron or steel tubes, as combining the greatest lightness
with the greatest strength, but angle iron, or any other like form of iron
girder may be substituted. Figure 10 is a side view, and Figure 11 is a plan
of a raft thus constructed; it consists of metal frames a, a, a, a, which are
each made in parts capable of being fitted together when required, and secured
with suitable fastenings. These frames when thus put together are by other
fastenings provided for the purpose fixed the one to the other in the position
shewn in the Drawing, so as to enclose a rectangular space; and a bottom

page_text: frame is introduced and fixed to the four side frames, which it serves to brace
securely. The caissons or vessels to give the requisite power of flotation are
then laid on the bottom frame, either in single or double tier, according to
the power of flotation required; if flexible caissons or vessels are employed,
they are inflated before placing them on the bottom frame. When all the
caissons or vessels are in their places, another frame similar to the bottom
frame is placed over them, and secured to the side frames to prevent the
caissons or vessels floating up. The top frame is then decked over, and the
raft is complete.
In witness whereof, I, the said Thomas Symes Prideaux, have hereunto
set my hand and seal, this Twenty-first day of April, in the year
of our Lord One thousand eight hundred and sixty.
THOMAS SYMES PRIDEAUX. (L.S.)