IMPROVEMENTS IN THE BUILDING OF WOODEN SHIPS, VESSELS, AND BOATS
Year: 1864

page_text: LETTERS PATENT to Peter Christie, of Greenock, in the County of
Renfrew, North Britain, Carver, for the Invention of "IMPROVEMENTS IN
THE BUILDING OF WOODEN SHIPS, VESSELS, AND BOATS."
Sealed the 14th June 1864, and dated the 26th January 1864.
PROVISIONAL SPECIFICATION left by the said Peter Christie at the
Office of the Commissioners of Patents, with his Petition, on the
26th January 1864.
I, PETER CHRISTIE, of Greenock, in the County of Renfrew, North Britain,
Carver, do hereby declare the nature of the said Invention of "IMPROVEMENTS
IN THE BUILDING OF WOODEN SHIPS, VESSELS, AND BOATS," to be as follows, that
is to say:
This Invention relates to certain improvements in the construction of the
hulls of wooden ships, vessels, and boats, and is for the purpose of imparting
greater strength generally, especially at the parts which are usually the
weakest, namely, the turn of the bilge and junction of the deck beams with
the frames at the top timbers. By this Invention the risk of damage to cargo
from deck and bottom leakage, as well as the liability to dry rot, are dimi-
nished, the last improvement resulting from the increased air space amongst
the timbers.
One improvement, according to this Invention, consists in making the frames,
which are of wood, of a greater depth or thickness athwartships than is at
present done, but of a less thickness in the longitudinal direction of the ship

page_text: or vessel, which arrangement produces greater space for the bilge water, at
the same time lessening the risk of its reaching the cargo; as the limber holes
are larger and more numerous the bilge water more readily reaches the
pumps.
Another improvement, according to this Invention, consists in securing the
deck-beams to the frames by means of a side plate or plates of iron, steel, or
other suitable metal, in lieu of the usual knees; and it is preferred to use iron
or steel plates at the fore end and middle portions of the vessel, but in the
after portion plates of copper, brass, or other suitable material may be used,
for this being the neighbourhood of the compass, local attraction is thus
avoided.
Another improvement, according to this Invention, consists in applying and
securing a plate or plates of iron or other suitable material opposite to the
second futtocks by which the turn of the bilge is strengthened.
Another improvement, according to this Invention, consists in the application
of bolts for fastening the outside planking to the frames, the bolt passing
through the outside planking into the frames; also through a
"coak" or
"cog" which is partially sunk into both plank and frame where they are in
contact.
Another improvement, according to this Invention, consists in securing the
outside planking to the inside or ceiling by bolts passing through the spaces
between the frames, which bolts are made of iron or other suitable metal.
Another improvement, according to this Invention, is that when iron or
steel bolts or plates are used they are secured from rust by an insulating
substance, which prevents the galvanic action on the iron resulting from
coppering the bottoms of wooden ships or vessels.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Peter Christie in the Great Seal Patent Office on the 25th
July 1864.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, PETER
CHRISTIE, of Greenock, in the County of Renfrew, North Britain, Carver,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-sixth day of January, in the year of our
Lord One thousand eight hundred and sixty-four, in the twenty-seventh year
of Her reign, did, for Herself, Her heirs and successors, give and grant

page_text: unto me, the said Peter Christie, Her special license that I, the said Peter
Christie, my executors, administrators, and assigns, or such others as I,
the said Peter Christie, 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 "IMPROVE
MENTS IN THE BUILDING OF WOODEN SHIPS, VESSELS, AND BOATS," upon the
condition (amongst others) that I, the said Peter Christie, my executors or
administrators, by an instrument in writing under my hand and seal, or under
the hand and seal of one of them, 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 Scal Patent Office
within six calendar months next and immediately after the date of the said
Letters Patent.
NOW KNOW YE, that I, the said Peter Christie, 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:-
My said Invention relates to certain improvements in the construction of
the hulls of wooden ships, vessels, and boats, and is for the purpose of
imparting greater strength generally, especially at the parts which are usually
the weakest, namely, the turn of the bilge and junction of the deck beams
with the frames at the top timbers. By this Invention the risk of damage to
cargo from deck and bottom leakage, as well as the liability to dry rot, are
diminished; the latter improvement resulting from the increased air space
amongst the timbers.
One improvement, according to this Invention, consists in making the
frames, which are of wood, of a greater depth or thickness athwartships than
is at present done, but of a less thickness in the longitudinal direction of the
ship or vessel, which arrangement produces greater space for the bilge water,
at the same time lessening the risk of its reaching the cargo; as the limber
holes are larger and more numerous the bilge water more readily reaches
the pumps.
Another improvement, according to this Invention, consists in securing the
deck beams to the frames by means of a side plate or plates of iron, steel, or
other suitable metal in lieu of the usual knees; and it is preferred to use iron
or steel plates at the fore end and middle portions of the vessel, but in the

page_text: after portion plates of copper, brass, or other suitable material may be used,
for this being the neighbourhood of the compass, local attraction is thus
avoided.
Another improvement. according to this Invention, consists in applying and
securing a plate or plates of iron or other suitable material opposite to the
second futtocks, by which the turn of the bilge is strengthened.
Another improvement, according to this Invention, consists in the appli-
cation of bolts for fastening the outside planking to the frames, the bolt
passing through the outside planking into the frames, also through a "coak"
or cog," which is partially sunk into both plank and frame where they are
in contact.
66
Another improvement, according to this Invention, consists in securing the
outside planking to the inside or ceiling by bolts passing through the spaces
between the frames, which bolts are made of iron or other suitable metal.
Another improvement, according to this Invention, is that when iron or
steel bolts or plates are used they are secured from rust by an insulating
substance, which prevents the galvanic action on the iron resulting from
coppering the bottom of wooden ships or vessels.
And in order that my said Invention may be properly understood, I shall
now proceed to describe the methods under which it may be used or prac-
tically carried into effect, reference being had to the several Figures upon the
explanatory Sheet of Drawings, which I have hereunto attached, and in which
similar parts are indicated by corresponding letters of reference.
The title of this Invention is intended to include all ships, vessels, and large
boats measurable by the tonnage laws of 1854, under the general desig-
nation of ships. For the purpose of thoroughly elucidating my present
Invention it is necessary that some preliminary remarks should be made in
reference to the operation of the old and new "tonnage laws" at the same
time the defects of the present system of "wooden ship building" should be
clearly pointed out. Wooden ships constructed according to the ordinary
methods are found possessed of numerous defects, which when investigated are
discovered to be mainly traceable to the system of measuring them on the
outside enjoined by the "old tonnage laws," and by this Invention it is
shewn that a remedy is found by adopting the system of inside measurement,
as the "new tonnage laws" direct. When ships are measured from the
outside (according to the old tonnage laws) the tendency of the builder
is to make them thin, so that they may hold a large cargo for their register
tonnage. This thinness renders them weak, especially at the turn of the bilge,
where the timbers are mostly "grain-cut." At the junction of the deck beams

page_text: and top timbers great weakness also exists, owing to the defective fastening of
these parts, whilst leakiness at the water-ways and covering boards is a common
result. To impart as much strength to the frames as possible under these
circumstances they are made broad in the fore-and-aft or longitudinal
direction of the ship, so that they come very near to one another, thus
leaving too little room between them for the bilge water, whilst the thinness or
narrowness of the frames in the transverse direction prevents "limber holes '
of sufficient size being made, particularly at the bilges, thus occasioning the
water to rise in the hold and spoil the cargo, and which injury "dunnage '
does not always prevent. This narrowness of the spaces between the frames
also prevents due circulation of air, which defect tends to produce dry rot; to
prevent which holes are made in the ceiling, and, in many instances, this is
left uncaulked, whereby particles of cargo and dirt slip down between the
frames and choke the "limber holes," consequently preventing the water
from reaching the pumps, whilst many ships have by these causes got water-
logged.
"
Another source of weakness is of the following nature:-To facilitate
or impart air amongst the frames, the greater number of the "futtocks"
are kept separate, as also the top timbers; the frame bolts, therefore,
do not hold sufficiently, and the different parts of the timbers are apt to
draw at the butts. This defect prevents the oakum from being sufficiently
caulked between the outside planks, the consequence of which is that the
vessel is defective in longitudinal strength.
These faults are not effectually remedied, as the "old tonnage laws" are
still in force under the designation of "builders' measurement," by which
ships are generally built, bought, and sold; therefore the proportions of the
frames are still essentially the same, and are likely to continue so as long as
this system of measurement is in use.
Having now pointed out the chief defects of the existing methods of building
"wooden ships," I shall proceed to describe the alterations and improvements
embodied in this Invention, which are for the purpose of preventing them as
far as possible.
The first improvement comprehended under this Invention is effected from
turning to account the great advantages resulting from the "new tonnage
laws of 1854, especially as regards the inside measurement of ships for.
register tonnage. By these laws I am enabled to make use of a property in
mechanics most important in relation to the proper distribution of material,
so as to obtain the maximum strength for the quantity usod, and which law
has not hitherto been applied to wooden ships on account of the system of

page_text: outside measurement enjoined by the "old tonnage laws." This mechanical
law may be explained in the following manner:-If a piece of wood is placed
on its flat side, between two supports, as a plank would be situated in the
floor of a house, its strength to resist fracture is reduced to the least; but if
it is placed on its edge like the joist which supports a floor, the strength is
greatly increased. This principle applied to the frames of wooden ships gives
the strength of which they are now so deficient.
The mode of accomplishing this improvement is by making the frames
broader the transverse way of the ship, and narrower the longitudinal way
than is now done; but to prevent any evasion of my Invention I do not
specify the degree of relative difference, taking care only to make it sufficient
to increase the strength of the frames athwartships.
Figure 1 of the accompanying Sheet of Drawings represents the midship
section of a ship constructed according to my Invention, that is, with the main
strength of the frames A in the transverse direction, these frames being made
of double the usual depth, but a greater or less depth may also be used.
Between the dotted line a, a, and the outer edge of the frame A is indicated
the ordinary thickness of the frames. As my authority, giving the usual size
of these frames, I take Lloyd's Register of British and Foreign Shipping,
Tables B and C. By employing the same amount of wood as that now used
for the frames of ships, but by making these frames broader in the transverse
direction of the ship, but narrower in the fore-and-aft direction, greater
room is allowed for the bilge-water, which therefore does not so readily rise
into the hold and Spoil the cargo. This construction of the frames also enables
limber holes of the necessary size to be made, and this is one of the most
important features of my improvement, becoming daily of more importance
from the fact of ships being now genorally built with less "rise of the floor"
tban hitherto; consequently when a ship "lists" over from pressure of sail, the
water flows into the "lee "bilge, and the limber holes at the central part are
frequently of no use. Figure 2, which represents à midship frame constructed
according to this Invention, shows that the limber holes C, C, may be made
to any useful extent as to number and size, without too much weakening of
the ship, and by them the water is freely conveyed to the pumps, which is
not the result from the present or existing constructions of wooden ships.
The part shaded in blue lines in Figure 2 represents the bilge water, and
by comparing the size of the limber holes which are made in the frames used
under this Invention with those of the usual size and form, it will be seen
with what facility this water can flow over the bottom of the vessel and is
prevented from accumulating in one part, as is the case in wooden ships con-

page_text: structed in the ordinary manner. At the upper part or at the junction of
the frames with the deck beams are shown the side plates G, Figure 3 ; these
plates are placed on either one or both sides of the frames and deck beams,
and held firmly to them by means of the several bolts marked g. These plates
or strengthening pieces may be made of either iron, steel, or any other metal
that may in practice be found suitable, and they may also be made of timber.
At Figures 1 and 2, these plates or strengthening pieces are also shown, as
well as those for increasing the strength of the bilge futtocks at H. 'These
may also be used on one or both sides of the futtocks, but it is found in most
cases preferable to use them on both sides, for in this way the strength of
the ship is very considerably increased. Figure 3 represents the upper
portion of one of my improved frames with the outside planks, ceiling,
and deck-beam united. The outside planks D are fastened to the frames A
by means of the bolts and "coaks" b and c. In those portions of the
planks D and ceiling E which are situated immediately outside and inside
of the frames A, as well as through the frames A, there are bored holes
to receive the bolts 6 and coaks c, by which all the three parts are united.
On applying and fitting a plank to the frames, holes are in the first place
bored through it and the frames, and when a sufficient number of such holes
are made, the plank is taken off, and those portions of the holes that meet
at the junction of the frames and outside planks are enlarged to a certain depth
sufficient to contain the "coaks" c, so that one half of the "coaks" shall
be in the plank, the other in the frame, these coaks being made to fit the holes
tightly. The bolt holes are continued on through the ceiling. On fixing the
three parts, namely, the frames, planks, and ceiling together, the coaks c are
first placed in the recesses formed to receive them in the frames A, the corre
sponding planks are then put on when the bolts bare passed through the
whole, and tightened up by the nuts on the inner side of the ceiling E. In
this arrangement I prefer that the bolts b should pass through the coaks c.
I do not however adhere to this, as in many cases the coaks might be placed
It is not the use of bolts and coaks
above, at one side, or below the bolts.
which is considered part of this Invention, but what I believe to be novel
is the peculiar application of them for considerably reducing the tendency
of the outside planks to shift upwards by the pressure of the oakum caulked
between the seams, which defect it is most desirable should be. overcome,
especially at the upper portion of a ship side, which is the part where this
At the keel each side
movement usually takes place to the greatest extent.
of the ship resists the caulking of the other, but as the gunwale is approached

page_text: the resistance gradually becomes less, but by adopting the bolts and coaks in
the manner herein-before described, they hold the top planking much more
securely, which arrangement permits the oakum to be driven into the seams
more firmly than at present, so that the outside planking is rendered much
more rigid, whilst that longitudinal weakness usually existing in wooden ships
is very much diminished. Figure 4 shows to a larger scale a portion of
the frame A with the outside planks D and ceiling E attached by bolts and
coaks, the upper portion of the frame A being broken away to show more
distinctly than in Figure 3 the position of the bolt 6 and coaks c. The
position of the other bolts and coaks are also shown in this Figure by the
Figure 5 shows the bolt and coak drawn in perspective
dotted lines d and e.
separately.
In Figure 6, a, a, a, a, is a cross section of the flooring timbers and first
futtocks. At Figure 6 is shown the usual way in which the material is
placed, the main strength being in the longitudinal direction of the ship in
which the spaces B, B, B, B, for giving air, and where the bilge water collects
are too small; this is drawn to the usual proportion. In Figure 7, A, A,
A, A, represent my form of construction and arrangement of material which
gives the strength required, and large spaces as at B, B, B, B, for air and
bilge water; C is the further side of the ship's hold; D is the keelson; E, the
ceiling plank; F, the outsido plank; G, the keel; and II, the false keel.
The two Figures 6 and 7 are given for the sake of comparing sections of
similar parts of a wooden ship; Figure 6 is a portion of a longitudinal
section of a wooden ship as at present constructed, Figure 7 being a similar
view of a portion of a ship constructed according to this Invention. On
comparing the old with the new system it will be observed that the same or
nearly the same quantity of wood is used in the new frames as in the old ones,
but that by the new disposition of such material a greatly increased strength
is obtained in the transverse section of the ship, whilst a much greater space
or room for bilge water and the circulation of air between the frames is also
obtained. On again referring to Figures 3 and 4 it will be seen that the
beads of the bolts bare sunk below the surface of the timbers D in such
manner that the head of the bolt is insulated from the outside copper, a plug
of wood or other suitable substance f being tightly driven in over the bead of
the bolt so as to produce this insulation. On the inside of the ship are nuts
for tightening up the bolts, but instead of this they may be driven tightly
through the planks and into the frames, or they may be screwed into the
wood, or clenched or locking bolts may be used.

page_text: Another part of this Invention consists in the application of bolts with
coaks for joining together the different parts of each frame instead of using
bolts only as has hitherto been done.
Another part of this Invention consists in the employment of bolts passing
through the outside planking in the spaces between the frames and ceiling,
at which place they are each fastened by a screw nut sunk into the wood, the
head being protected on the outside by insulation as herein-before described
in reference to the bolts passing through the frames themselves. In this
second case no coaks are necessary. The advantage gained from this
arrangement is that the planks are held still more firmly without cutting up
the frames by unnecessary holes.
Another improvement, according to this Invention, is the employment of
iron knees or brackets similar to those which are used to support an ordinary
shelf as shown at h, Figures 1, 2, and 3, these knees being attached by bolts
to the under side of the deck and the inner side of the outside planking, their
use being to increase the resistance to the caulking, and thus preventing
leakage at the waterways and covering boards.
Another improvement, according to this Invention, is the application of straps
of wood or metal attached vertically to the inside of the outside planking at
those portions situated between the frames, this arrangement being for the
purpose of still further stiffening the outside planks by increasing their
resistance to be shifted by the caulking, which increases the longitudinal
strength of the ship. Another cause of weakness in the sides of wooden ships
results from the method under which "chain plates" are ordinarily employed.
From the fact of their being carried to only a short distance down the ship's
side they possess a strong tendency to lift the planks above them from the
lowest one, still so long as these "chain plates "are fixed to the outside of
the ship there are practical objections to arrange them lower down, for
when the vessel should list over from the pressure of sail they would drag
through the water and thus impede her. progress.
According to this Invention the additional thickness of the ship's side would
allow of the required "spread of rigging" without putting the "chain plates"
outside, and it is preferred that they should be placed on the inside and taken
far down; and they may in many instances be carried across the ship by a
connecting plate, thus materially strengthening the hull.
Another improvement, according to this Invention, consists in the application
of plates of metal on the interior side of the butt joints of the outside planking
so as to impart greater longitudinal strength to the hulls of wooden ships,
these plates may be affixed by means of bolts or screws.

page_text: Another improvement, according to this Invention, consists in thoroughly
insulating the bolts by which the frames, planks, and ceiling are joined
together. This may be effected in various ways. According to one system of
insulation the holes are syringed with a solution of gutta percha, or it may be
introduced in any other manner that may be found suitable, and after the
holes are become coated with this substance the bolts are introduced. Or
instead of this the bolts are first dipped into some substance, such as a mixture
of shellac and spirits of wine, or other solvent, or any other glutinous or other
mixture or substance that may be found suitable, such as marine glue, pitch,
tar, or a solution of india-rubber, and then introduced into the holes; or
powdered shellac or other material may be first introduced into the holes in a
pulverized state whilst the bolts are put in warm, so as to melt the material,
and which, when liquid, will cover them. The chief use of insulating the bolts
being for the purpose of as far as possible preventing them from rusting.
After the bolts are thus inserted and tightened up, plugs of wood or other
suitable substance are driven in over them in the manner herein-before
described.
Having now described and particularly ascertained the nature of my said
Invention, and the manner in which the same is or may be used or practically
carried into effect, I would observe in conclusion that I do not confine
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 true principles and main features of my said 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 mode of constructing wooden ships, as
berein-before described, or any mere modification thereof.
Second, the arrangement and construction of the frames of wooden ships, as
herein-before described, or any mere modification thereof.
Third, the application of side plates on one or both sides of the deck beams
and frames, as herein-before described, or any mere modification thereof.
Fourth, the application of side plates at the second futtocks and turn of the
bilge, substantially as herein-before described, or any mere modification
thereof.
Fifth, the peculiar application of the "coak" and bolt for fastening on the
outside planks, as herein-before described.
Sixth, the peculiar application and introduction of bolts into the spaces
between the frames, substantially as herein-before described.

page_text: Seventh, the insulation of the bolts, as herein-before described, or any
mere modification thereof.
Eighth, the application of metal brackets for the purpose of strengthening
wooden ships at the "gunwale," as herein-before described, or any mere
modification thereof.
Ninth, the application of straps of metal or timber on the inside of the
wooden ships to better enable them to withstand the caulking, at the same
time imparting longitudinal stiffness to the ship, as herein-before described, or
any mere modification thereof.
Tenth, the method of fixing the chain plates on the interior of the vessel,
as herein-before described.
Eleventh, the extension of the ceiling boards beneath the deck, in the
manner herein-before described, or any mere modification thereof.
Twelfth, the adaptation of plates of metal at the butt joints of the timbers
in the manner herein-before described, or any mere modification thereof.
In witness whereof, I, the said Peter Christie, have hereunto set my
hand and seal, this Twenty-first day of July, One thousand eight
hundred and sixty-four.