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United States Patent Office.


Specification forming part of Letters Patent No. 673, dated April 
4, 1838.

To all whom it may concern:

Be it known that I, Henry Higginson, of Boston, in the county of 
Suffolk and State of Massachusetts, have invented certain 
Improvements in the Mode of Building Ships and other Vessels Used 
in Navigation; and I do hereby declare that the following is a 
full and exact description thereof.

The object which I have in view in my improvements in the 
construction of ships and other vessels for naval service is so 
to arrange, combine, and unite the materials of which they are 
built as to give to them a much greater degree of strength and 
stability than they usually possess without any material increase 
in their cost or loss of room for stowage, and to accomplish this 
end I have devised several new modes of procedure, which may be 
used in whole or in part, as may be preferred.

One of my improvements in building ships or other navigable 
vessels with a view to increase their strength consists in 
placing outside of the timbers composing the frame of vessels two 
or more courses of planking running horizontally and parallel to 
each other, or as nearly so as may be.

I am aware that double planking is not new, vessels having been 
constructed entirely of plank, such vessels having been formed 
upon a mold and the layers of plank having been made to cross 
each other at various angles, so as in their combination to 
retain the form given to them without the use of a frame. The 
frames of vessels have also been double-planked, with the grain 
of the two layers crossing each other, so as to constitute a 
brace by such crossing. I am aware, also, that thick plank has 
sometimes been scarfed to a certain extent to enable it to be 
bent the more readily over quick curves, as in passing round the 
bows of a vessel; but my plan is distinguished from each of these 
in object and means. My object is to obtain great longitudinal 
strength by causing the grain of each layer of plank to run 
horizontally, or nearly so, and confining the layers together by 
treenails, spikes, bolts, or other means.

Each layer of plank is to be well calked, and between the layers 
tarred paper, tarred cloth, or paper or cloth covered with paint, 
or a layer of any suitable kind of cement, is to be interposed, 
as has been repeatedly done when cross-planking has been resorted 
to. The double calking, the close fitting of the layers of plank, 
and the intervention of a substance which resists the percolation 
of water, in connection with the stiffness derived from the 
employment of two or more layers of plank running horizontally, 
will tend to prevent the admission of moisture between the 
planking, and consequently insure its durability. For this same 
purpose of durability I omit the inner ceiling now so generally 
used, believing the same to be positively and greatly detrimental 
in promoting decay by confining the wet and moisture between that 
and the planking.

Another improvement consists in strengthening the frame by a new 
mode of applying diagonal braces and vertical and horizontal 
ties, either in combination with said two or more courses of 
horizontal planks or with plank employed in the usual manner in a 
single course. Such braces may be variously modified in size, 
arrangement, and material, as may be determined by the builder. 
They are to be placed between the timbers of the frame, and they 
may be flush with the outside of said timbers, so that the plank 
shall be in contact with them; or they may be so placed as to 
allow a flux of air between them and the plank, as may be 
preferred. In the former case the plank is to be fastened to them 
as it is now fastened to the ordinary ribs or other parts of the 
frame. I intend sometimes to dispense with a considerable portion 
of the ribs as now used in building vessels and to allow the 
diagonal braces and the ties to constitute a large portion of the 
frame and to serve as a substitute for ribs.

Figure 1 in the accompanying drawings will serve to show the 
manner in which diagonal braces may be applied. This figure may 
be taken as representing a section of about six feet square�say 
the usual height between decks�though a larger section would 
generally be preferably. R R R are the ribs, seen from the 
inside. They are supposed to be eight inches square with ten-inch 
spaces between them. B B are braces of plank, say, twelve inches 
wide and three inches thick let into the ribs where they cross 
the same, so as to be flush on the inside; or, instead of plank, 
they may be of timber of suitable size. They are braced against 
the two outer ribs of the section, as seen in the drawings, and 
are driven hard to their bearings by wedges. Bolts or other 
fastenings may be employed to keep the braces in place, and the 
wedges also are to be so secured that they cannot work out by the 
working of the vessel. The timbers of each rib I intend to 
connect endwise by dovetail, which is a new mode of fastening 
them, more secure and efficient than the old-fashioned chock or 
than Seppings dowel, as neither of these has any tendency to 
resist a pull endwise.

In deep vessels whose sides continue down in a direction nearly 
perpendicular below the lower deck, I place diagonal braces there 
also. They may also be continued on the bottom; but I do not deem 
this necessary, there being but little tendency in a vessel to 
twist or strain sidewise.

The sectional drawing above referred to exhibits more timber than 
will be found necessary when diagonal braces are properly used, 
as the ribs may be reduced in number and size, as may also be the 
case with the braces, a thing which must necessarily be governed 
by the size of the vessel, the judgment of the builder, the 
material employed, and other circumstances. In this drawing the 
braces are represented as placed so as to be flush with the 
inside of the ribs; but the better way is to place them flush 
with the outside of the ribs in contact, or nearly so, with the 
planking, and the planking to be fastened thereto as now fastened 
to the ribs, the said braces being first wedged hard to their 
bearings. By this method the braces will take place of the ribs 
and much timber be saved, while at the same time will be attained 
in a great degree that inflexibility which is the main object of 
my improvements, and which is the design of bracing in all kind 
of structure. Inflexibility has generally been thought 
inapplicable to ship-building; but it would seem more needful in 
vessels than anywhere else, as unlike most other structures they 
are subject to strains in all directions, being sometimes 
sustained or upheld by the two ends and sometimes by the center 
only, and under the circumstances of ordinary use they are 
strained more or less in all directions, producing a tendency to 
loosen and open the plank-seams, which nothing but inflexibility 
in the frame-work can continuously resist.

I do not pretend that there is anything absolutely new in the 
application of diagonal braces or of ties, these having been 
applied in nearly all possible ways in ordinary carpentry, as in 
the framing of bridges and other structures of timber. The 
novelty of my improvement in this part consists in employing 
devices well known in carpentry to the perfecting of naval 
architecture in the essential points of strength and tightness, 
and the manner of effecting this object as herein described I 
believe to be new and useful.

Fig. 2 in the accompanying drawings exhibits another method of 
using braces and ties, which I deem preferable to those already 
described. Horizontal bands of stout timber, generally two, as A 
A B B, are carried entirely round the vessel and dovetailed, 
clamped, or otherwise securely fastened to the stem and stern 
posts. The several pieces of timber composing these bands are 
also to be dovetailed, clamped, or otherwise secured together 
endwise, so as to form horizontal or longitudinal ties, which 
will resist the force of any strain lengthwise to which they are 
likely to be subjected. The band A A is to be placed nearly on a 
level with the upper deck, and the other B B ten, fifteen, or any 
other suitable number of feet below it, according to the size of 
the vessel. These two bands are connected and prevented from 
separating by upright timbers C C, placed at such distance apart 
as may be preferred, and dovetailed, clamped, or otherwise 
securely fastened to the horizontal bands, and thus forming 
vertical ties. Brace-timbers D D are then placed diagonally and 
driven hard to their bearings by wedges, as already described, 
thus rendering the frame-work inflexible and unyielding. Although 
the bands of timber have been spoken of as being placed 
horizontally, this term is not used in an absolute sense, as in 
vessels nearly every part of the structure is more or less 
curved, and these bands may be made to curve either upward or 
downward in any required degree without interfering with their 
efficiency or changing their mode of action.

It has been already observed that the principle of applying 
braces and ties may be modified in numerous ways, while the same 
end will be obtained, and differences of this sort have been 
exemplified in Figs. 1 and 2.

Fig. 3 is another variation, in which A A and B B are portions of 
the bands of timber before described, and D D are diagonal 
braces, the vertical ties C C (shown in Fig. 2) being omitted, 
and in place of which bars or bands of iron E E are passed over 
the upper and under the lower band of timber, so as to allow of 
and resist the action of the wedges in straining all up tight.

As some of the methods of using diagonal braces here described 
bear a resemblance to the plan invented by Sir Robert Seppings 
and since adopted in the British naval service, it may be well to 
point out in what respects they differ from mine in order that my 
improvement may be better understood. Seppings braces are simply 
diagonal timbers placed on the inner side of the ribs and 
fastened upon them (not let into them) by bolts, the whole 
breadth of said braces projecting into the hold of the vessel. 
This plan of bracing, though greatly conducive to strength, and 
therefore an important advancement in the art of ship-building, 
is defective in several respects. One defect is the space thus 
occupied in the hold. Another is that the whole strain comes upon 
the bolts, which always yield more or less, and a third is that 
braces thus arranged cannot be forced to their bearings, without 
which diagonal braces on any plan lose half their efficiency.

Another improvement I have invented is applicable to all modes of 
framing, and is for the purpose of strengthening the garboard 
strake, or where the planking joins the keel, stern and stern 
posts, and this is effected by doubling the planking for a few 
feet in width all along that line, and thinning off the edge of 
the outer layer which runs along parallel with that line. For 
this purpose I form a double rabbet along the line of the 
junction of the planking with the stem and stern posts and also 
along the keel in such a manner as that the edges of the inner 
and outer planks shall have a separate bed or resting-place, 
allowing in this way the ends and edges of the outer layer of 
plank to overlap the inner layer, each resting and being fastened 
within the rabbet adapted to it in thickness and extent.

Fig. 4 represents a cross-section of the keel, as also of the 
stem or stern posts, a a being the rebate for the inner and b b 
that for the outer layer of plank.

My next improvement consists in using diagonal braces midship, 
which are to slope upward and outward from the keel or keels on 
to the ends of the deck-beams or against the upper band of timber 
before described or against the side timbers near the level of 
the upper deck, as shown at Fig. 5, where c is the keel, d the 
brace, and e the deck-beam, the object and effect of which device 
being to strengthen the vessel generally, and also to cause the 
weight of the ship and cargo to be upheld in part by the side 
timbers instead of being as at present wholly sustained by the 
floor from the upward pressure of the water. This plan would 
alone prove of especial advantage in the flat-bottomed vessels 
now so generally used, the floors of which have a strong tendency 
to arch inward, and consequently to open the seams near the 
bilge. Instead of or in addition to the manner of placing the 
diagonal braces just described, braces from the keel may slope up 
fore and aft, so that their upper ends may press upon the centers 
of such beams, and in this manner transfer the strain to the 
sides. In like manner, the better to support the stem and stern 
and to counteract the tendency to hogg, I intend sometimes to use 
braces extending from the keel to those parts at an angle of 
about forty-five degrees with the horizon. These braces sloping 
upward form the keel fore and aft, may cross each other, and be 
multiplied at pleasure, and this would greatly increase the 
strength of the vessel in all respects in the same manner and 
perhaps to a greater degree than the diagonal braces on the 
sides, and they would thus form a continuous diagonal frame-work 
running along midship similar to that on the sides.

A further improvement, which is applicable to nearly all vessels, 
is to place between the floor-timbers at each side of the keel 
and at the distance of six or eight feet therefrom (more or less, 
according to circumstances) stout pieces of timber running 
lengthwise of the vessel, said pieces to be in a line with each 
other and to butt up against the floor-timbers, while they are 
also capable of being wedged up at one end. In Fig. 6, � 
represent such timbers, g being the keel and h the floor-timbers. 
These pieces, which chock in between the floor-timbers and are 
wedged fast, assist greatly in strengthening the bottom and in 
preventing hogging or bending downward at the ends, as in so 
doing the deck and upper works must stretch or partially separate 
while the bottom is compressed. Whatever, therefore, has the 
effect of counteracting either of these tendencies must be so far 
useful in preventing their taking place. In combination, 
therefore, with the foregoing device I dovetail to the deck-beams 
the timbers or planks running lengthwise of the vessel from one 
deck-beam to another, and secure them further by clamps or other 
means, so that they shall bear a powerful tension without the 
danger of yielding; or for the same purpose of resisting the 
tendency to stretch in the upper works I use a thicker plank on 
deck�say four inches�on the under side of which I cut grooves of 
one or one and one-half inch depth, in which grooves the 
deck-beams are to rest and be wedged hard, and thus the whole 
deck may be rendered more capable of resisting the longitudinal 
strain before mentioned.

To secure the various timbers together, whenever treenails are 
used, I make such treenails of a larger size than would admit of 
their being driven in the ordinary way, and I then compress and 
condense such treenails, so that they may easily be driven into 
the holes prepared for them and become tight by expansion. This 
compressing may be effected by means of grooved rollers, by 
forcing the treenails through suitable holes in a metallic plate, 
or by any other adequate means; but to the method of effecting 
this I do not mean to make any claim, but only to their use; or, 
they may be made of compressed wood and used with equal effect.

I have spoken of the employment of wedges for tightening the 
diagonal braces of the frame and for other purposes; but I intend 
to carry the system of wedging still farther by using them in all 
cases wherever they can be applied for giving firmness to the 
frame by forcing all parts to their proper bearings. This mode of 
tightening, as formerly observed, has been extensively used in 
carpentry, but has been overlooked in the framing of vessels, to 
which object I believe the application to be essentially new, and 
also of great importance in making the whole frame firm and 
inflexible, and wedges thus used are designed to become a 
stationary and permanent part of the frame.

Having thus fully described the various improvements made by me 
in the manner of building ships or other vessels, and also the 
way in which the same may be carried into effect, I do hereby 
declare that the following are the improvements in this art which 
I claim as having been invented by me and which I desire to 
secure by Letters Patent:

1. The use of two or more courses of planking running 
longitudinally upon the vessel, arranged in the manner and for 
the purpose described.

2. The employment of diagonal braces placed between the ribs of 
the vessel, or so placed that the braces themselves may form part 
of the ribs, and so arranged as to be in contact with the outer 
planking, or nearly so�that is to say, without any timber, plank, 
or other substance of considerable thickness between the said 
braces and planking�the said braces being at the same time so 
adjusted that they may be forced hard to their bearings by means 
of wedges, the whole of which arrangement having for its object 
the producing a greater degree of inflexibility in the frame than 
has been ordinarily attained. In making this claim it is to be 
understood that I confine myself to the strengthening of the hull 
of the vessel by wedged braces between the ribs or by using 
braces as a substitute for ribs, a thing which will be readily 
distinguished from such frame-work as has sometimes been used 
above the deck in certain vessels, (as on steamboats for 
supporting the boilers and other parts of the machinery,) and 
not, therefore, properly connected with ship-building. By 
referring to the description of such braces in this specification 
it will be seen that I do not intend to limit myself to any 
particular form or combination of them, but to vary this and the 
material employed as I may think proper, while the plan and 
object remain entirely the same.

3. The combination of two or more courses of planking outside the 
frame with the use of diagonal braces of any form or material, 
believing such a combination to be new and eminently conducive to 
both strength and tightness.

4. The use of one or more bands of timber surrounding the vessel 
horizontally, or nearly so, and employed in the manner and for 
the purposes set forth.

5. The employment of iron bands passed over and under the upper 
and lower horizontal bands of timber as a substitute for such 
ties of timber as I sometimes use for the purpose of resisting 
and sustaining the force of the wedges employed with the diagonal 
braces, as described.

6. The double rabbet along the keel and the stem and stern posts 
to receive the double planking and to allow the outer layer of 
plank to overlap the inner layer, which said double rabbet and 
double planking may be used with or without my other improvements 
herein described.

7. The use of diagonal braces sloping up from the keel or keels 
on to the ends or center of the deck-beams or to the side timbers 
of the vessel, or to the stem or stern posts, in the manner and 
with the intention herein made known.

8. The manner of using one or more ranges of stout timber between 
the floor-timbers running lengthwise of the vessel and so 
constructed as to be wedged up, whether used alone or in 
combination with dovetailed ties uniting and bracing the 
deck-beams in order to prevent hogging, as described.

9. The use of plank grooved in the manner described for receiving 
the deck-beams, and thus add strength to the upper works 
generally. . The employment of the system of wedging not only as 
applied to my diagonal braces, but to braces of any form or 
material or to any other part of the ship's frame, as being the 
best and most convenient method of forcing all parts to their 
bearings, and thereby producing a great degree of firmness and 
inflexibility, which I hold to be essentially necessary in this 
sort of structure.

I do not claim the use of wedges in the art of ship-building 
generally, but I limit my claim to the use thereof for the 
purpose of stiffening the frame in all its parts, and as 
stationary appendages thereto.

Boston, January 17, 1838.


Witnesses: Robert Rogers, G. M. Higginson.