IMPROVEMENTS IN CONSTRUCTING IRON SHIPS OR VESSELS
Year: 1875

page_text: LETTERS PATENT to Alexander Melville Clark, of 53, Chancery Lane,
in the County of Middlesex, Patent Agent, for the Invention of
"IMPROVEMENTS IN CONSTRUCTING IRON SHIPS OR VESSELS."-A commu-
nication from abroad by Richard Powell, of Washington, in the
District of Columbia United States of America..
Sealed the 16th October 1875, and dated the 26th August 1875..
COMPLETE SPECIFICATION filed by the said Alexander Melville Clark
at the Office of the Commissioners of Patents, with his Petition
and Declaration, on the 26th August 1875, pursuant to the 9th
Section of the Patent Law Amendment Act, 1852.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ALEXANDER
MELVILLE CLARK, of 53, Chancery Lane, in the County of Middlesex
(Patent Agent), send greeting.
WHEREAS I am in possession of an Invention for "IMPROVEMENTS
IN CONSTRUCTING IRON SHIPS OR VESSELS," and have petitioned Her Majesty
to grant unto me, my executors, administrators, and assigns, Her Royal
Letters Patent for the same, and have made solemn Declaration that
it has been communicated to me from abroad by Richard Powell, of
Washington, in the District of Columbia, United States of America.

page_text: NOW KNOW YE, that I, the said Alexander Melville Clark, do hereby
declare that the following Complete Specification, under my hand and
seal, fully describes and ascertains the nature of the said Invention, and
in what manner the same is to be performed, in and by the following
statement, reference being had to the accompanying Sheet of Drawings,
and to the letters and figures marked thereon (that is to say) :-
The objects of this Invention are,-
:-
First. An improved plan of constructing the hulls of iron vessels so
as to have a fair and smooth outside surface.
Second. To secure wood backing or filling for the reception of wood
planking to be covered with copper sheathing, so that none of the
fastenings will pass through or penetrate the outer iron plating or skin
of the. vessel, particularly in the portion to be immersed.
Third. To lessen the rolling motion of iron vessels with advantage to
their speed and steering.
The accompanying Drawing shows sections of the side of a ship and
details of the mode of building herein described with designs for tools.
The letters of reference in the Specification will fully explain the
Drawing.
To secure the first object (a fair outer surface) I attach to the timbers
seam straps, running fore and aft, for the reception of the outside
plating. These seam straps are rolled with a tongue in the centre for
the plating to seam against. The thickness of the tongue should be
about the same as that of the plating, and its depth, in and out, about
one-tenth of an inch more. Where the plating is heavy the edge of the
tongue is to be rolled hollow, that is, the edges should project an eighth
or a tenth of a inch beyond the surface of the plating, and the hollow or
centre of the tongue be on a line with the surface of the plating (see
Figure 6 A). These projecting edges are dressed down into the seams.
with a round faced hammer, thus filling and caulking both seams, at the
same time leaving little if any trimming. The outside plating is
rivetted to the seam straps in the usual manner. Where light plating
is used the tongue of the seam strap may be square on its outer edge,
projecting, say, a tenth of an inch, as it can be dressed down with a
hammer, caulking the seams without bruising the plating, making
smooth work in little or no trimming. The seams can also be caulked
by setting a sharp cold chisel into the centre of the tongue, opening at

page_text: sufficient to fill the seams, after which the score, Figure 6 B, will be
filled with putty when painting. If caulked in this way the tongue of
the seam strap must be rolled full the depth of the outside plating; this
will require no trimming. When the plating and tongue are heavy two.
scores, Figure 6 B¹, will be necessary in caulking, in which case the
tongue should be about one and one-third the thickness of the plating
(see Figure 6) B, B¹).
To obtain the second object, that of securing the wood backing or
'filling, I use seam straps running fore and aft, rolled with a projecting
tongue in a T shape, forming a seam strap and stringer. The corners
in this seam strap must be rolled sharp and square, saving the slight
taper to be given to the tongue, so that the plating will lie close when
properly rivetted, and be caulked in the usual manner. After caulking
angle irons are rivetted to both sides of this projecting tongue (see
Figures 1, 3, and 6C), which must project sufficiently to receive half
the thickness of the wood filling within the angle irons. The wood
filling or backing between the tongue stringers is to lie close against the
outside plating of the hull, the ends being grooved to fit over and within
the angle irons on the tongued seam strap (see Figures 1, 2, and 3. D).
The pieces of this filling reverse their angle, bracing each course, as
shown in the Drawing, Figure 1 D, the angle to be not less than the
width of the widest timber used in the filling, set off on a square on the
opening to be filled. An angle of not less than this is necessary to
ensure good work in fitting and getting the timber into place, but it
should not exceed forty-five degrees. Every third piece of filling should
have a short bolt d. driven through the angle irons into each end, the
upper ends of the upper course finishing under the double angle iron,
shown at E, Figures 1, 2, and 3, the bolts to be driven through its outer
face; the purpose of these fastenings is to resist the caulking. To
facilitate the driving of these bolts all the courses must be filled at the
same time. The upper edge of the double angle iron must be rivetted
to the outside plating of the vessel. The caulking of the filling should
commence at both ends of the courses at the same time, and all of the
seams in the courses be caulked before the butt seams running fore and
aft over the seam straps. After being caulked and planed off fair, if
desired, the sheathing copper can be put on the filling, but for first class
work the filling should be covered with sheathing boards or planks, and
this also. caulked and planed off before putting on the sheathing copper

page_text: (see Figures 1 F). This system of sheathing can be applied to vessels
already built. For such vessels a double angle iron (see Figure 2G)
must. first be rivetted to the plating and frame of the hull. A single
angle iron is then rivetted to this double angle iron; or a single angle
iron and iron may be used, and the wood filling or backing is. fitted
and worked as before described. The mode of casing the keels with the
wood and securing and filling or backing thereto is illustrated at J, K,
and L of Figures 2, 3, and 7 of the Drawing.
-
To secure the third object of this Invention, to lessen the rolling
motion of iron vessels, I use a seam strap with tongue stringer, às already
described (see Figure 5 H). The stringer here shown projects outside
the plating, forming keels on each seam from the main keel to near the
water line. These side keels may be formed on the alternate seams only,
as may be advisable, according to the form and width of the plating of
the vessel. These stringers by their depth and number will keep the
vessel steady, and prevent the rolling motion. Their projection clear of
the outside plating must vary according to the size and form of the
vessel, say, from six to twelve inches. They form bilge keels, and there
is no danger of their carrying away or straining the plating, the number
of them giving little or no opportunity to roll, and consequently there is
but little strain on the stringers. Oscillation being prevented the pro-
pelling power can be used to its full extent. These outside stringers
or keels are to run along the main body of the vessel for, say, three-
fifths of the length of the vessel on the water line, and be rounded off at
the ends. They will thus make but little if any resistance to the free
passage of the vessel through the water, while by keeping her steady
there will be a marked effect on the steering and speed, the strong
transverse friction of rapid rolling being avoided. The number and
position of these stringers also serve to strengthen the main body of the
vessel where strength is most needed, and protect the outside skin should
she touch the ground. The edges of the plating having their bearing
against the stringer are more substantially secured than when they seam
against each other. The stringer giving a fair firm base for either side
acts also as a stiffener between the frames for caulking. On this account
the stringers usually placed on the inside of the hull can be reduced in
size, so that the outside stringers need not be wholly an additional
weight to the hull. This T iron stringer can be applied to vessels]
already built. In this case it must be laid on the outside and rivetted
through every frame it passes over, in the manner shown at I, Figure 4'

page_text: In building with the seam strap tongue stringer the frames can be
spaced further asunder than is usual, reducing the weight almost as much
as the seam strap will increase it, and make a much stronger vessel in
very nearly the same weight of material.
.
In using the seam straps and tongues the plating is increased in width
by about the laps and tongues, and the number of streaks of plating is
thereby reduced.
Having described the nature of the Invention, and the manner of
performing the same, I declare that what I claim as new and desire to
secure by Letters Patent is,-
First. A tongued seam strap, the tongue being rolled hollow on its
outer edge, and adapted to be combined in the manner herein described
with the plating of iron vessels, so as when dressed down with a round
faced tool to caulk the seams and give a smooth surface, substantially as
set forth.
Secondly. The method described of caulking the seams in iron vessels
by scoring the tongue of the seam strap, substantially as shown and
specified.
30
Thirdly. The combination of angle irons and seam straps, for the
purpose of securing wood backing in the manner set forth and shown.
Fourthly. The wood backing applied in a diagonal position, for the
purpose of strengthening and bracing vessels, in combination with the
angle irons, substantially as shown and described.
Fifthly. In iron vessels, the T iron constituting stringers and seam
straps, applied in the manner described, for the purposes set forth.
In witness whereof, I, the said Alexander Melville Clark, have
hereunto set my hand and seal, this Twenty-fifth day of August,
in the year of our Lord One thousand eight hundred and seventy-
five.