IMPROVEMENTS IN THE CONSTRUCTION OF IRON SHIPS AND VESSELS
Year: 1868

page_text: LETTERS PATENT to Thomas Barnabas Daft, of Cleves Lodge, Church
St., Chelsea, Civil Engineer and Naval Architect, for the Invention
of IMPROVEMENTS IN THE CONSTRUCTION OF IRON SHIPS AND VESSELS."
PROVISIONAL SPECIFICATION left by the said Thomas Barnabas Daft
at the Office of the Commissioners of Patents, with his Petition, on
the 1st January 1868.
I, THOMAS BARNABAS DAFT, of Cleves Lodge, Church St., Chelsea,
Civil Engineer and Naval Architect, do hereby. declare the nature of
the said Invention for "IMPROVEMENTS IN THE CONSTRUCTION OF IRON SHIPS AND
VESSELS," to be as follows:-
The object of this Invention is to facilitate the construction of iron
ships and vessels, economize time, and to produce a stronger, more
seaworthy, and safer vessel in every respect than has heretofore been
built.
The Invention relates to iron clad ships of war as well as to every
other description of sea-going vessel for transport, merchant service,
or the naval war department. The "lines" determined upon are
straight ones in place of curved lines always hitherto used more or

page_text: less for all sea-going vessels, curves at the bows, curves at the sterus,
curves for the bilge, scarcely a straight line to be found about a vessel;
now in these new vessels all the lines are to be straight, as a rule
rectangular on plan and in section throughout the whole length, in
short a true girder with ends tapering upwards from the bottom to the
deck at both ends, both ends being alike, as a rule the angle I prefer
is one in four, thus if the depth of the vessel be 10 feet I begin
the angle at 40 feet from each end, and make a straight line from the
bottom to the deck forming a sharp wedge for going over the water, and
not so much through it as is the case with the present vessels. The
bottom of these vessels on my rectangular principle is quite flat, and
the sides at exactly right angles to the bottom; the deck as a rule quite
flat, always of iron of about the same strength as the bottom and sides,
and all hatches and openings securely made by gussets and angle iron
from danger of rupture at or about them, thus a true, exceedingly strong,
and stiff vessel is formed in a very simple and cheap manner, having
the true form for sailing or steaming at an improved pace. As she will
draw less water for her tonnage than common vessels she will have a
tendency to pass over the water instead of plunging into and through
it, and she will have "lines" both fore and aft at the angles I have
mentioned, and which are calculated to meet and leave the water with
the least possible resistance. This arrangement of rectangular section
throughout the whole hull gives great facilities for receiving and dis-
posing of powerful machinery on board; there is no longer any necessity
of distorting the simple and useful proportions of steam engines in
order to fit them for the arbitrary "lines" of curved hulls. These new
vessels may have the very best known propo:tions of land engines
applied to them, and excepting in very small craft, say 60 feet long and
under, they may and should have engines at both ends, and as a rule
four distinct and separate paddle wheels with eight cylinders and a full
complement of boilers and the usual accessories.
being independent of each other rudders may be dispensed with. The
steering may be performed by controlling the speed of a paddle or
reversing it, and this may be done by the helmsman with the aid of a
lever on deck, as will be readily understood by an engineer. If these
new vessels are to sail as well as steam there are great facilities afforded in
them for such an arrangement, and in such a case all the wheels may
be raised and the vessel, being of the type for sailing and rigged
accordingly, put under canvas in a very few minutes; such a vessel, a
The paddle wheels

page_text: "sailing steamer," will not differ one iota in her lines from a vessel for
steaming alone the rectangular principle with wedge shaped ends will
be truly carried out, but she may have a keel, say simply of solid plate
iron, running along her taper ends even with her flat bottom and fair
with the ends of the ship, and at one end or if desirable at both ends a
rudder or rudders may be fixed. If a yacht be an object on this
rectangular principle keels and a rudder would probably be required
under certain circumstances to prevent her getting away to leeward; but
it must always be remembered that the vertical side of this type of
naval architecture offers all along the length of the immersed portion of
the hull an immense impediment to leeway; probably without keels to
this new form a vessel of the yacht class would hold on a straight course
when the common round bottom with all the keel they can give it
would go away to lecward. The foregoing has reference to sailing
yachts only. For a steam yacht of small dimensions, say under 35
tons, the machinery would most likely have to be placed in the middle
of the hull, and as usual in the ordinary construction the very best part
of the vessel occupied by the boiler and engines, but above that tonnage
for whatever purpose, yachting, trading, or for warfare, the boilers and
engines may be most conveniently and profitably placed towards the
ends, and the middle of the vessels kept for cabins, saloons, or guns
respectively. In all cases where steam and paddles are employed the
paddles will be encased in recesses made partly into the wedges and partly
into the hulls of the vessels, they will be entirely out of sight and com-
paratively safe. Great convenience will arise from the entire absence of
the common cumbrous projections attendant upon the present plan of
outside paddles, and inside a large amount of expense and danger will
be avoided by the paddle shafts being geared at both ends to the
connecting rods by simple and very safe discs instead of complicated
cranks. In fact not only is the enormous expense of bending the
framing and plates throughout a vessel by this system avoided, but
the work is so much the stronger, the iron is not disturbed in its
the compression
fibre, its original strength is preserved intact,
of the material on the inner curves and the extension of it on
the outer curves always more or less injuring its strength is entirely
avoided; moreover, throughout the whole work from the laying of
the bottom to the launch, and ever afterwards, the work of construction
and management is rendered extremely simple, safe, and easy.
In

page_text: vessels of war the line should be angular above and partly under water
on the sides as well as the ends, and bulwarks receding from a given line
of the rectangular outside dimensions must be provided to a convenient
height and to a similar angle 1 in 4. At a certain distance under water
the hull must have vertical sides in order to obtain displacement and
accommodation for stores and machinery. A formidable and very ser-
viceable vessel of war could be constructed for a very little money
comparatively and in a very short space of time, and if her principal
dimensions were 600 feet long, by 100 wide and 30 feet deep she would
carry the very heaviest armaments yet nade or in course of construction,
and yet draw but about 18 feet of water.
In the construction of these rectangular vessels I employ by preference
Tiron for the ribs, and I give the edges of the face of it an angle thus
in order to admit of straps of teak wood or any other convenient
T
material being put in diagonally between the ribs and hammered
or forced to right angles with them, and so with or without the addition
of screws, as will be hereafter explained, make a sound water-tight
joint. With T iron of the section shewn and suitable in size to the
vessel to be built, I proceed to cut it to lengths, mark, and punch
it, but I employ certain tools for marking and punching as follows:-
Having fairly marked the places for punching the rivet holes in the
usual way I take a centre punch having a collar fitted to it, the outside
diameter of which collar is exactly the diameter of the mark of the
hole to be pierced; by applying this punch and collar evenly with the
mark and striking the punch a blow a centre indentation will be
produced in the mark, if not deep enough then a blow or two more with
the punch with or without the collar will make it so.
Now I employ
for the piercing punch a punch with a small projecting centre
on its
face which may be felt to enter the centre punched marks and so the
iron may be accurately punched. This mode of marking the rivet holes
by a centre punch, and having a piercing punch with a projecting
centre on its face, is to be applied to the process of piercing all
the plates as well as the framing. The plating on this new principle
should all be arranged so as to come directly on to the ribs or frames;
no lapping of one plate over the other or the "in-and-out fashion
of plating should be allowed, because it necessitates liners, and longer
and therefore weaker rivets where the liners occur. The liners them-
selves add weight but no strength to the vessel, while the absolute
"

page_text: necessity of using long rivets instead of short stiff ones creates a great
evil in the shape of a weakness in a great many parts of the ship.
Now the arrangement of plating right against the ribs or framing
throughout the whole vessel gives great additional, aud what is very
important, uniform strength to and throughout the whole hull. It
becomes with concentric punching, good rivetting, and compact and
uniform plating one homogeneous mass. The edges of all the plates
are to be left about their own thickness apart. All joints meeting on the
frames which are of T iron as before described are to be separated by a
space equal to their own thickuess and the edges left from the shears
at right angles. All the edges crossing the ribs are to be sheared or
planed to an angle of 2 or 3 degrees, and form when rivetted up a slot
or opening about the width of the thickness of the plates and with the
widest side on the outside of the skin, into these slots or openings teak
strips are to be tightly hammered and of a length to pass over several
of the ribs, they are to be pared flush with the inside and outside of
tho hull; in this way a very perfect and durable caulking is made of
all the joints. It is iron with teak caulking in comparison with wood
and oakum caulking.
In order to add to the strength and durability of this caulking I
introduce straps of teak, say covering strips, inside the skin running
between each rib, and of a width equal to about 3 times that of the
groove, and about 1 times its depth in thickness; the ends of all these
strips must be bevilled to agree with the bevil on the edges of the T iron,
and being introduced diagonally must be driven parallel to the grooves
and be very tightly fixed; in addition to which screws may be driven
from the inside through the strip and into the teak caulking, bringing
the strip tight up against the inside iron skin of the vessel, and holding
against the escape of the teak caulking under any circumstances. If
desirable the teak caulking may be driven in with hot pitch, narino
glue, or any suitable cement, and a similar substance may be applied
to the inside of the skin between it and the strip. In this or a similar
manner this teak caulking can be made perfectly water-tight and durable,
and will remain so under circumstances of a vessel's straining, labouring,
or "yawing" in a seaway, which would open the butts of common vessels
and send them to the bottom.
As regards the corrosion aud fouling of iron vessels it will be found
that the teak caulking forms a good foundation for nailing or screwing

page_text: on zinc sheathing; copper or yellow metal is not recommended because
however well they may be insulated by wood or other non-conducting
material there is always a great risk run of accidental contact being
made, when the iron commences at once a course of degradation and
the copper or yellow metal begins forthwith to foul, and under these
circumstances it is impossible to discover where the iron is most
affected, and it may be eaten through the very bottom in six weeks
after contact, and yet it is impossible to discover the full extent of
damage without entirely stripping the whole hull of the vessel of this
copper and wood and exposing the entire surface of iron. These are
the casualties that iron ships cased in wood and also composite ships
are liable to when or wherever they are sheathed with copper or
yellow metal or any metal electro-negative to iron. It was this electro-
galvanic action which compelled wooden shipbuilders to adopt copper
or yellow metal bolts soon after copper sheathing was in vogue. The
wooden vessels with iron fastenings and copper sheathing soon destroyed
the iron fastenings and bolts, and although copper fastenings were 4
or 5 times as expensive and not so strong weight for weight, yet it
was impossible safely to avoid the use of them; now zinc alters all these
conditions. With wooden vessels iron bolts and fastenings may be
used, and if their heads and faces come flush with the outside timber
of the vessel, so that actual metallic contact be made between them
and the zinc sheathing, the effect will be when moistened by sea
water that the iron bolts will be completely protected from corrosion
by electro-galvanic action, which action being positive as regards the
zinc will keep the surface exfoliating or peeling away at a rate as near
as possible to that of copper and yellow metal, and consequently and
certainly will the zinc be as clean as those metals and last as long.
Without contact with iron zinc is liable to become foul, but this is
the worst than can ever happen even on a wooden iron fastened vessel,
for it, the zinc, could not possibly injure the iron fastenings. Zinc
therefore is the proper metal to sheath an iron vessel, and irrespective
of the enormous extra expense of copper or yellow metal, and the great
inconvenience and extra expense of applying those metals, the danger
of using them under all the best known means of insulation ought to
deter scientific men from running the risk of foundering some of our
finest vessels by applying a sheathing liable to destroy the hull of
the ship upon which it is put.
'
In order to render every facility for sheathing an iron vessel I intro-

page_text: duce in the course of their construction plugs for nailing into the
middle or edges of the plates. When the plates are punched for
rivetting on the framing of the vessel I mark a number of places
clear of the rivot holes and in convenient situations for fastenings
such as nails, rivets, or screws for holding on the sheathing; in
these situations, which I centre punch, I drill holes about th
through the plates, and about inch diameter. Now if I have deter-
mined to rivet on my sheathing I drop into these holes a previously
prepared zinc or iron stud or rivet, having a small shoulder on it going
just below the edge of the hole, and by one single sharp blow with a
properly prepared punch, struck with a hammer, the rivet or stud is
firmly closed in. When the plates are rivetted in position on the
frames, or before if desirable, a template is applied to the rivets, and
their situations transferred to a sheet of zinc prepared to suit the place,
and holes are pierced in it accordingly; it is then easily applied, the
holes threaded over the rivets, and a head formed on each. by a suitable
punch so shaped as to make the heads partly sink into a hollow formed
to receive them and partly stand up above the level of the zinc, but only
forming a flat smooth head, the remainder of the sheet is to be nailed
against the teak caulking and well secured. When iron or zinc rivets ure
to be used as above described the holes may be drilled ouly through the
plates and be found sufficient; but I prefer teak wood plugs and iron
or zinc nails to be driven into them through the zinc sheathing to hold it
In this case I prefer the holes about ths through the thickness of
the plates of iron; these are to be drilled as before described previously
to the plates being rivetted on to the framing of the vessel, the wooden
plugs are also to be driven tightly in and the heads cut off to stand up
of an inch or thereabouts above the face of the plates. The plates should
be properly numbered, and a sheet of zinc corresponding to each number
applied in order, and by means of a semi-elastic faced haniner blows
are to be struck about over the slightly projecting teak heads of the
plugs, and their precise position ascertained by an embossed mark on
the zinc sheet corresponding with every plug; the sheathing being
all numbered and marked can be pierced and applied at convenience.
If iron nails be used, say cominon "clouts," the piercing of the zinc
may be dispensed with, for the points of the "clouts" will pierce
their way through the zine and enter and hold in the plugs with
extraordinary tenacity, whilst their heads will go well home into and
upon the bed formed by the slightly projecting head of the teak plug,
on.

page_text: making all as flat, snug, and fast as possible. The edges or those parts
of the sheets of zinc coming over the teak caulking can always be well
secured thereto by screws or nails. As iron is absolutely protected by
zine from fouling and corrosion the common clouts may be safely used,
or the "wood screws" of iron may be introduced wherever it may seem
desirable.
SPECIFICATION in pursuance of the conditions of the Letters Patents,
filed by the said Thomas Barnabas Daft in the Great Seal Patent
Office on the 1st July 1868.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, THOMAS
BARNABAS DAFT, of Cleves Lodge, Church St., Chelsea, Civil Engineer
and Naval Architect, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the First day of January, in the year of our
Lord One thousand eight hundred and sixty-eight, in the thirty-first
year of Her reign, did, for Herself, Her heirs, and successors, give and
grant unto me, the said Thomas Barnabas Daft, Her special licence that
I, the said Thomas Barnabas Daft, my executors, administrators, and
assigns, or such others as I, the said Thomas Barnabas Daft, 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 "IMPROVEMENTS
IN THE CONSTRUCTION OF IRON SHIPS AND VESSELS," upon the condition
(amongst others) that I, the said Thomas Barnabas Daft, 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
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 Barnabas Daft, do hereby
declare the nature of the said Invention, and in what manner the same

page_text: is to be performed, to be particularly described and ascertained in and by
the following statement thereof, that is to say:-
The object of this Invention is to facilitate the construction of iron ships
and vessels, economize time, and to produce a stronger, more seaworthy,
and safer vessel in every respect than has heretofore been built.
The Invention relates to iron-clad ships of war as well as to every
other description of sea-going vessel for transport, merchant service, or
the naval war department. The "lines" determined upon are straight
ones in place of curved lines always hitherto used more or less for all
sea-going vessels, curves at the bows, curves at the sterns, curves for
the bilge, scarcely a straight line to be found about a vessel; now in
these new vessels all the lines are to be straight, as a rule rectangular
on plan and in section throughout the whole length, in short, a true
girder with ends tapering upwards from the bottom to the deck, at both
ends, both ends being alike as a rule, the angle I prefer is one in four;
thus if the depth of the vessel be 10 feet I begin the angle at 40 feet
from each end, and make a straight line from the bottom to the deck,
forming a sharp wedge for going over the water, and not so much
through it as is the case with the present vessels. The bottom of
these vessels on my rectangular principle is quite flat, and the sides
at exactly right angles to the bottom; the deck as a rule quite flat,
always of iron of about the same strength as the bottom and sides, and
all hatches and openings securely made by gussets and angle iron from
danger of rupture at or about them; thus a true, exceedingly strong, and
stiff vessel is formed in a very simple and cheap manner, having the
true form for sailing or steaming at an improved pace. As she will draw
less water for her tonnage than common vessels she will have a tendency
to pass over the water instead of plunging into and through it, and
she will have "lines" both fore and aft at the angles I have men-
tioned, and which are calculated to meet and leave the water with
the least possible resistance. This arrangement of rectangular section
throughout the whole hull gives great facilities for receiving and dis-
posing of powerful machinery on board. There is no longer any necessity
of distorting the simple and useful proportions of steam engines in order
to fit them for the arbitrary "lines" of curved hulls.
vessels may have the very best known proportions of land engines
applied to them, and excepting in very small craft, say 60 feet long
and under, they may and should have engines at both ends, and as a
rule 4 distinct and separate paddle wheels with 8 cylinders and a full
These new

page_text: complement of boilers and the usual accessories. The paddle wheels
being independent of each other rudders may be dispensed with. The
steering may be performed by controlling the speed of a paddle or
reversing it, and this may be done by the helmsman with the aid of a
lever on deck, as will be readily understood by an engineer. If these
new vessels are to sail as well as "steam" there are great facilities
afforded in them for such an arrangement, and in such a case all the
wheels may be raised and the vessel, being of the type for sailing and
rigged accordingly, put under canvas in a very few minutes; such a
vessel, a "sailing steamer," will not differ one iota in her lines from
a vessel for steaming alone. The rectangular principle with wedge-
shaped ends will be truly carried out; but she may have a keel, say,
simply of solid plate iron, running along her taper ends, even with her
flat bottom and fair with the ends of the ship, and at one end or if
desirable at both ends a rudder or rudders may be fixed. If a yacht
be an object on this rectangular principle, keels and a rudder would
probably be required under certain circumstances to prevent her getting
away to leeward; but it must always be remembered that the vertical
sides of naval architecture offers all along the length of the immersed
portion of the hull an immense impediment to leeway; probably with-
out keels to this new form a vessel of the yacht class would hold on a
straight course when the common round bottom with all the keel they
can give it would go away to leeward. The foregoing has reference to
sailing yachts only. For a steam yacht of small dimensions, say under
35 tons, the machinery would most likely have to be placed in the
middle of the hull, and as usual in the ordinary construction the very
best part of the vessel occupied by the boiler and engines, but above
that tonnage, for whatever purpose, yachting, trading, or for warfare, the
boilers and engines may be most conveniently and profitably placed
towards the ends, and the middle of the vessels kept for cabins, saloons,
or guns respectively. In all cases where steam and paddles are
employed the paddles will be encased in recesses made partly into
the wedges and partly into the hulls of the vessels; they will be entirely
out of sight and comparatively safe. Great convenience will arise from
the entire absence of the common cumbrous projections attendant upon
the present plan of outside paddles, and inside a large amount of
expense and danger will be avoided by the paddle shafts being geared
at both ends to the connecting rods by simple and very safe discs instead
of complicated cranks. In fact not only is the enormous expense of

page_text: bending the framing and plates throughout a vessel by this system avoided,
but the work is so much the stronger, the iron is not disturbed in its
fibre, its original strength is preserved intact, the compression of the
material on the inner curves and the extension of it on the outer curves'
always more or less injuring its strength is entirely avoided; more-
over throughout the whole work, from the laying of the bottom to
the launch, and even afterwards the work of construction and manage.
ment is rendered extremely simple, safe, and easy. In vessels of war the
lines should be angular above and partly under water on the sides as well
as the ends, and bulwarks receding from a given line of the rectangular
outside dimensious must be provided to a convenient height and to a
similar angle 1 in 4. At a certain distance under water the hull must
have vertical sides in order to obtain displacement and accommodation for
stores and machinery. A formidable and very serviceable vessel of war
could be constructed for a very little money comparatively and in a very
short space of time, and if her principal dimensions were 600 feet long
by 100 wide and 30 feet deep she would carry the very heaviest arma-
ments yet made or in course of construction, and yet draw but about 18 feet
of water.
Figure 1 is a plan, and Figure 2 is a side view, partly in section, of an
iron-built ocean steam vessel constructed according to my Invention. The
main deck a and the bottom 6 of the vessel are both perfectly flat and
rectangular, and the ends c, c, which are similar, and which also are flat,
are inclined at about 1 in 4, that is to say, at a very easy slope such as to
admit of the vessel being driven over the water at a high speed. The
sides d, d, are vertical, but the bulwarks e, e, incline rapidly inwards so as
to reduce the resistance of the wind to the vessel, and give to the deck an
efficient protection from the waves; thus every part of the exterior of the
vessel is flat; this greatly facilitates the construction and renders the
structure very strong, regard being had to the weight of materials employed
in it. Either paddle wheels, or screws, or both may be employed, and it
is preferred to have propelling apparatus at both ends. The paddle wheels
work in trunks or cases formed in the vessel for their reception, as is
shown, and the bottom of the trunk or case of each wheel is open with
the exception of a strong curved plate passing across it immediately
under the wheel; this plate serves both to guide the water advantageously
as it passes the wheel and also to strengthen the structure. Each paddle
wheel is driven independently by two steam cylinders operating on
opposite sides of the wheel; then the vessel has four double engines,

page_text: and the steering may be effected by the regulation and due control of
these engines. Screws may be used in conjunction with or in place of
paddle wheels, as the Drawings show, and cach screw shaft is driven
independently by a pair of engines.
Figure 3 is a perspective view of a cutter yacht constructed according
to my Invention. As will be seen the peculiarities of the yacht are the
same as those of the larger vessel already described, that is to say, it has
a flat bottom and a flat deck, parallel the one to the other and connected
by flat sides at right angles thereto and by flat ends at an easy incline of
one in four or thereabout.
Figure 4 is a transverse section of a war ship of similar construction
but with armour-plate inclines g, g, passing around it. In these inclines
the gun ports are formed as is shown in the half section Figure 5.
Figure 6 shows a section of the angle of the armour plating, the plates
being welded at the line where the two inclines meet. The paddle wheels
in this arrangement are placed only just within the vessel's side, so that
they may be used with the maximum effect to steer the vessel. The outer
steam cylinders to drive the wheels are partly contained in the recess
between the armour plated inclines.
In the construction of these rectangular vessels I employ by preference
Tiron for the ribs, and I give the edges of the face of it an angle, thus
in order to admit of straps of teak, wood, or any other con-
T
venient material being put in diagonally between the ribs and
hammered or forced to right angles with them, and so with or
without the addition of screws, as will be hereafter explained, make a
sound water-tight joint.
In Figure 7 the T iron is shown in section at a, a, the skin plates of
the ship rivetted upon it at b, b; c is a teak caulking, herein-after
further referred to; and d are teak strips on the inside of the vessel, and
which may be employed either only to cover the joints in the places, as is
shown in section at Figure 8, throughout, so as to make a flush surface
with the flanges of the T iron, beyond which surface however the web of
the iron and the rivet heads project. With T iron of the section shewn
and suitable in size to the vessel to be built I proceed to cut it to lengths,
mark, and punch it, but I employ certain tools for marking and punching
as follows-Having fairly marked the places for punching the rivet holes
in the usual way I take a centre punch having a collar fitted to it, the
outside diameter of which collar is exactly the diameter of the mark of

page_text: the hole to be pierced; by applying this punch and collar evenly with
the mark and striking the punch a blow a central indentation will be
produced in the mark; if not deep enough then a blow or two more with
the punch with or without the collar will make it so. Now I employ
for the piercing punch a punch with a small projecting centro on
its face, which may be felt to enter the centre punched marks, and
so the iron may be accurately punched. This method of marking
and punching is illustrated by the Figures 9. a is a piece of metal
accurately marked with a stencil plate or otherwise at the places where
it is required to be punched; b is a collar of the same diameter as the
marks formed on the metal a, and it is placed accurately upon them;
c is a centre fitting truly in the collar 6, and which when struck forms a
mark which is accurately in the centre of the required hole, and which
may be deepened if necessary; d is the punch of the punching machine
with a small cone on its face; this cone enters the centre punch
hole, and by its incline and the incline of this hole it corrects the
position of the plate, provided that it has been presented with sufficient
accuracy for the point of the cone to descend anywhere within the iudent
formed by the punch, and care must be taken that this condition is
fulfilled. This mode of marking the rivet holes by a centre punch and
having a piercing punch with a projecting centre on its face is to be
applied to the process of piercing all the plates as well as the framing.
The plating
on this new principle should all be arranged so as to come
directly on to the ribs or frames, no lapping of one plate over the other,
or the "in-and-out' fashion of plating should be allowed, because it
necessitates liners, and longer and therefore weaker rivets where the
liners occur; the liners themselves add weight but no strength to the
vessel, while the absolute necessity of using long rivets instead of short
stiff ones creates a great evil in the shape of weakness in a great many
parts of the ship. Now the arrangement of plating right against the ribs
or framing throughout the whole vessel gives great additional, and what
is very important, uniform strength to and throughout the whole hull.
It becomes with concentric punching, good rivetting, and compact and
uniform plating, one homogeneous mass. The edges of all the plates are
to be left about their own thickness apart. All joints meeting on the
frames, which are of T irou as above described, are to be separated by a
space equal to their own thickness, and the edges left from their shears at
right angles. All the edges crossing the ribs are to be sheared or planed
to an angle of 2 or 3 degrees, and form when rivetted up a slot or

page_text: opening about the width of the thickness of the plates, and with the
widest side on the outside of the skin. Into these slots or openings teak
strips are to be tightly hammered, and of a length to pass over several of
the ribs they are to be pared flush with the inside and outside of the
hull. In this way a very perfect and durable caulking is made of all the
joints. It is iron with teak caulking in comparison with wood and oakum
caulking. In order to add to the strength and durability of this caulking
I introduce strips of teak, say covering strips, inside the skin running
between each rib, and of a width equal to about 3 times that of the groove,
and about 1 times its depth in thickness; the ends of all these strips
must be bevilled to agree with the bevil on the edges of the T iron, and
being introduced diagonally must be driven parallel to the grooves and be
very tightly fixed, in addition to which screws may be driven from the
inside through the strip and into the teak caulking, bringing the strip
tight up against the inside iron skin of the vessel, and holding against the
escape of the teak caulking under any circumstances. If desirable the
teak caulking may be driven in with hot pitch, marine glue, or any suitable
cenient, and a similar substance may be applied to the inside of the skin
between it and the strip. In this or a similar manner this teak caulking
can be made perfectly water-tight and durable, and will remain so under
circumstances of a vessel's straining, labouring, or yawing, in a seaway, which
would open the butts of common vessels and send them to the
bottom.
A portion of the side of a ship thus constructed and caulked is shown.
at Figure 10, and a horizontal section of the same at Figure 11, and also
to a larger scale at Figure 12; here rib frames a built up of angle irons
with a web plate between them are represented, but in place thereof T iron
ribs may be used as is shown at Figure 7. The skin plates bare of such
a length as to extend over the usual number of ribs, and the vertical joints
between the plates are made in every case on the ribs as is shewn, the
plates not coming into contact with each other, but having a space left
between them equal to their thickness, into which the filling strip e of teak
is tightly driven. The horizontal joints between the plates are also left
open and teak strips are driven into them, as is shown at Figure 8. The
edges of the plates should be somewhat inclined so as to form a taper
recess the better to hold the filling strip, which is further secured by
attaching it by screws to the covering strip on the inside.
As regards the corrosion and fouling of iron vessels it will be found
"L

page_text: that the teak caulking forms a good foundation for nailing or screwing
on zinc sheathing. Copper or yellow metal is not recommended, because
however well they may be insulated by wood or other non-conducting
material there is always a great risk run of accidental contact being
made, when the iron commences at once a course of degradation, and the
copper or yellow metal bogins forthwith to foul, and under these circum-
stances it is impossible to discover where the iron is mest affected, and
it may be eaten through the very bottom in six weeks after contart, and
yet it is impossible to discover the full extent of damage without entirely
stripping the whole hull of the vessel of the copper and wood and
exposing the entire surface of iron. These are casualties that iron ships
cased in wood, and also composite ships, are liable to when or wherever
they are sheathed with copper or yellow motal, or any metal electro-
negative to iron. It was electro-galvanic action which compelled
wooden shipbuilders to adopt copper or yellow metal bolts soon after
copper sheathing was in vogue. The wooden vessels with iron fastenings
and copper sheathings soon destroyed the iron fastenings and bolts, and
although copper fastenings were 4 or 5 times as expensive and not so
strong, weight for weight, yet it was impossible safely to avoid the use
of them; now zinc alters all these conditions. With wooden vessels iron
bolts and fastenings may be used, and if their heads and faces come flush
with the outside timber of the vessel so that actual metallic contact be
made between them and the zinc sheathing, the effect will be, when
moistened by sea water, that the iron bolts will be completely protected
from corrosion by electro-galvanic action, which action being positive as
regards the zinc will keep the surface exfoliating or peeling away at a rate
as near as possible to that of copper and yellow metal, and consequently
and certainly will the zinc be as clean as those metals and last as long.
Without contact with iron zinc is liable to become foul, but this is the
worst that ever can happen, even on a wooden iron fastened vessel, for it,
the zinc, could not possibly injure the iron fastenings. Zinc therefore is
the proper metal with which to sheathe an iron vessel, and irrespective of
the enormous extra expense of copper or yellow metal, and the great
inconvenience and extra expense of applying those metals, the danger of
using them under all the best known means of insulation ought to deter
scientific men from running the risk of foundering some of our finest vessels
by applying a sheathing liable to destroy the hull of the ship upon which
it is put.

page_text: In order to render every facility for sheathing an iron vessel 1 introduce
in the course of their construction plugs for nailing into the middle or
edges of the plates. When the plates are punched for rivetting, on the
framing of the vessel I mark a number of places clear of the rivet holes,
and in convenient situations, for fastenings such as nails, rivets, or screws
for holding on the sheathing in the situations which I centre punch, I drill
holes about through the plates, and about inch diameter. Now if I
have determined to rivet on my sheathing I drop into these holes a
previously prepared zinc or iron stud or rivet having a small shoulder on
it going just below the edge of the hole, and by a blow with a properly
prepared punch, struck with a hammer, the rivet or stud is firmly closed
in. When the plates are rivetted in position on the frames, or before if
desirable, a template is applied to the rivets, and their situations trans-
ferred to a sheet of zinc prepared to suit the place, and holes are pierced
in it accordingly; it is then easily applied, the holes threaded over the
rivets, and a head formed on each by a suitable punch so shaped as
to make the heads partly sink into a hollow formed to receive them,
und partly stand above the level of the zinc, but only forming a flat
smooth head. When iron or zinc rivets are to be used, as above
described, the holes may be drilled only rd through the plates and be
found sufficient.
Figure 13 shows a section of a plate into which a stud for retaining
sheathing is to be fixed, and also of the punch or tool which is used in
the operation, as will be seen; after the shallow hole has been bored the
stud is placed in it, and the ring formed edge of the punch when the
punch is struck closes in the sides of the hole on to the stud. Figure 14
is a plan of the plate with the rivet holes and the stud holes formed in it.
But I prefer teak wood plugs and iron or zinc nails to be driven into
them through the zinc sheathing to hold it on. In this case I prefer
the holes about ths through the thickness of the plates of iron. These
are to be drilled, as before described, previously to the plates being
rivetted on to the framing of the vessel. The wooden plugs are also to
be driven tightly in, and the heads cut off to stand up rath of an inch or
thereabouts above the face of the plates. The plates should be properly
numbered, and a sheet of zinc corresponding to each number applied in
order, and by means of a semi-elastic faced hammer blows are to be
struck about over the slightly projecting teak heads of the plugs, and
their precise position ascertained by an embossed mark on the zine sheet

page_text: corresponding with every plug. The sheathing being all numbered and
marked can be pierced and applied at convenience. If iron nails be used,
say common "clouts," the piercing of the zinc may be dispensed with, for
the points of the clouts will pierce their way through the zinc and enter
and hold in the plugs with extraordinary tenacity, whilst their heads will
go well home into and upon the bed formed by the slightly projecting head
of the teak plug, making all as flat, snug, and fast as possible. The edges or
those parts of the sheets of zinc coming over the teak caulking can always
be well secured thereto by screws or nails. As iron is absolutely protected
by zinc from fouling and corrosion the common clouts may be safely used,
or the "wood screws" of iron may be introduced wherever it may seem
desirable. The method of securing the sheathing where wooden plugs are
used is clearly shewn in Figure 15, which is a transverse section through
the plate and through the plugs.
In witness whereof, I, the said Thomas Barnabas Daft, have hereunto
set my hand and seal, this Twenty-sixth day of June, in the year
of our Lord One thousand eight hundred and sixty-eight.
THOMAS B. DAFT. (L.B.)