IMPROVE- MENTS IN THE CONSTRUCTION OF FLOATING BREAKWATERS ADAPTED FOR THE FACILE AND ECONOMIC FORMATION OF HARBORS OF REFUGE, AND OTHER SUCH PURPOSES
Year: 1860

page_text: LETTERS PATENT to Bamfyeld Henri Francis Macnamara, of Great
Yarmouth, in the County of Norfolk, for the Invention of "IMPROVE-
MENTS IN THE CONSTRUCTION OF FLOATING BREAKWATERS ADAPTED FOR THE
FACILE AND ECONOMIC FORMATION OF HARBORS OF REFUGE, AND OTHER SUCH
PURPOSES."
Sealed the 27th March 1861, and dated the 2nd October 1860.
PROVISIONAL SPECIFICATION left by the said Bamfyeld Henri Francis
Macnamara at the Office of the Commissioners of Patents, with his
Petition, on the 2nd October 1860.
I, BAMFYELD HENRI FRANCIS MACNAMARA, of Great Yarmouth, in the
County of Norfolk, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN THE CONSTRUCTION OF FLOATING BREAKWATERS ADOPTED FOR THE
FACILE AND ECONOMIC FORMATION OF HARBORS OF REFUGE, AND OTHER
PURPOSES," to be as follows:-
Large enclosed hollow cylinders or pontoons constructed of wood or metal,
in suitable lengths, are floated and moored end to end, and linked together in a
line with their axes, large iron blocks being fixed between each of the said
cylinders or pontoons, to which a mooring shackle is attached provided with
friction rollers to lessen the wear of the same and facilitate rotary motion in
the said cylinders, and thereby reduce to the minimum the effect of the waves
on the same. The said cylinders or pontoons carry a diagonally-braced framing,
furnished with friction rollers at its points of support, so as to enable the said
framing to oscillate freely. One or more tiers of piles are suspended from the
said framing; the piles being solid, or consisting of strong cast-iron pipes, as
may be necessary. These are braced and tied together, and are connected
with the upper tier or framing by means of link joints; the object being to

page_text: obtain both strength and flexibility. The weight of the lower tier of piles is
intended to preserve the framing in a vertical position to enable it to meet the
direct force of the waves without giving way to them, but to break them on
an inclined surface. The inclination of the framing being formed by and in
proportion to the weight of the suspending piles, and the force exerted on the
breakwater by the waves.
These floating breakwaters are intended to be placed in two lines, which
may be arranged in a circular, oval, triangular, oblong, polygonal, or a straight
line, as may be required. The framing of the inner line of breakwaters is to
be closer than the framing of the outer line, and may be close sheeted, if
advisable. The inner line of breakwaters should be placed at such a distance
from the outer line as to prevent the waves which have passed over it
recovering their velocity or power, which will become entirely expended on the
inner line of breakwaters, thereby securing smooth water in the basin beyond,
into which vessels will be admitted by appertures sufficiently wide to afford
every access to it for the largest ships; and such entrances will be indicated
at night by lights fixed in cradles secured to the cylinders or pontoons at each
end of the outer line of breakwaters.
Floating breakwaters, constructed as herein described, may be built with
great facility in sections on land, and may be moored in position at any time
of the tide, or in any weather. They will be economical in construction, and
may readily be repaired.
SPECIFICATION in pursuance of the conditions of the Letters Patent
filed by the said Bamfyeld Henri Francis Macnamara in the Great
Seal Patent Office on the 2nd April 1861.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, BAMFYELD
HENRI FRANCIS MACNAMARA, of Great Yarmouth, in the County of Norfolk,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Second day of October, in the year of our Lord
One thousand eight hundred and sixty, in the twenty-fourth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said Bamfyeld Henri Francis Macnamara, Her special licence that I, the
said Bamfyeld Henri Francis Macnamara, my executors, administrators, and
assigns, or such others as I, the said Bamfyeld Henri Francis Macnamara,
my executors, administrators, and assigns; should at any time agree with, and
no others, from time to time and all times thereafter during the term therein

page_text: 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
FLOATING BREAKWATERS ADAPTED FOR THE FACILE AND ECONOMIC FORMATION OF
HARBORS OF REFUGE, AND OTHER SUCH PURPOSES," upon the condition (amongst
others) that I, the said Bamfyeld Henri Francis Macnamara, my executors
or administrators, by an instrument in writing under my, or their, or one of
their hands and seals, should particularly describe and ascertain the nature
of the said Invention, and in what manner the same was to be performed,
and cause the same to be filed in the Great Seal Patent Office within
six calendar months next and immediately after the date of the said Letters
Patent.
NOW KNOW YE, that I, the said Bamfyeld Henri Francis Macnamara,
do hereby declare the nature of my said Invention, and in what manner the
same is to be performed, to be particularly described and ascertained in and
by the following statement thereof, reference being had to the accompanying
Drawings, and to the figures and letters marked thereon (that is to say) :-
According to my said Invention large enclosed hollow cylinders or pontoons
of suitable lengths, constructed of wood or metal, or of wood coppered or
covered with zinc, are floated and moored end to end, and linked together in
a line with their axes with a strong coupling, fitted with a large iron drum
keyed on a strong axis provided with friction rollers let into the outer edge, so
as to reduce to the minimum the wear of the mooring shackles, and to
facilitate rotary motion in the said pontoons. The pontoons are divided into
water-tight compartments by such divisions as may be deemed requisite or
necessary for securely guarding against accident. The ends are constructed
solid and rounded, so as to allow of the greatest play and flexibility when acted
upon by the shortest wave. The axis of the said drum coupling is connected
with the axis of the pontoon by means of a strong double link or shackle.
The axes of the pontoon works in a chamber fixed in the end of the pontoon
provided with a solid head, fixed solid to prevent extension. The said
chamber is provided with vulcanized india-rubber packing at each end to act
as a double buffer, and counteract any injurious action between the pontoons.
In some cases it may be necessary to fix a water-tight pipe right through the
centre of the pontoon, through which to connect the interior ends of each con-
necting rod by a strong iron cable, thereby to form a continuous chain through
the whole line of pontoons from end to end. The said cylinders or pontoons
carry a diagonal cradling, consisting of two lines of piles strongly framed
together, and suspended from the cylinders on each side, properly braced and

page_text: provided at the points of contact and suspension with large iron friction
rollers fitted to and working on bands of case-hardened iron fixed round the
said cylinders, so as to lessen the wear of the same, and allow the framework
to oscillate freely. The said piles may be of wood or iron, and are strongly
connected together with weal ties, screw bolts, and nuts. The length of the
piles to be in ordinary cases from ten to fifteen feet above, and from fifteen to
twenty feet below the line of flotation. The lower end of the said piles are
weighted, so as to keep the breakwater in a vertical position; and when the
depth of water will admit of it, one, two, or more tiers of piles, either of solid
case-hardened iron or of wood may be added and weighted as required. Such
piles are suspended from the upper tier by wrought-iron link joints connected
with the ground by chains and kedges, or other similar anchors or moorings.
The length of the said chains to be just sufficient to reach the ground and
take hold of the anchors without slackness, and yet without strain; the object
being to attain both strength and flexibility, and allow the breakwater to
accommodate itself to the angle given to it by the varying force of the waves,
yet being sufficiently strong and rigid to meet the direct force of the waves,
and without giving way to them to break them on their self-formed incline.
The incline being formed by and in proportion to the vertical weight of the
piles and the force exerted by the passing wave.
The mooring chains of the breakwater may be of ordinary link cable, or flat
or round wire rope, and are being continuous passed round the pontoons and
thence down to and round rollers, each fixed by a lewis to a large block of
granite, concrete, the solid rock, or otherwise, as may be most suitable for the
locality. The said mooring chains on the sea face would be best laid out at
such a distance as to form an angle of not more than 25°, and those on the
inside an angle of not less than 45° with the line of flotation. Such mooring
chains to be coated with a preparation of india-rubber or gutta percha.
In some cases it may be desirable to connect inclined planes of wood or
iron close sheeted and fitted on the outer mooring cables, so as to form an
artificial slope for the purpose of breaking the force of the waves before they
reach the upright and suspended breakwater. For this purpose the upper
and lower line of the continuous band forming the mooring cable will be con-
nected together by struts and braces of wood or iron attached to a moveable
hollow girder of half-inch rolled plate iron, provided with friction rollers, and
laid on and along the lines of the cable from about five feet from the face of
the upright breakwater to a point about twenty feet under line of flotation;
strong timbers being securely bolted on the upper plate of the hollow girder,
and diagonally laid sheeting to be securely fixed to the timbers.

page_text: The upper portion of the two lines of piles forming the breakwater and over
the pontoons may be so framed as to allow of a water-tight sloping deck and a
communication underneath to afford facility for periodical examination. The
said deck to be sloped outwards, so as to give the greatest possible deflection
to the wind from the surface of the inner water; and a chamber may be con-
structed as a cabin for one or two men as a crew for the protection and care
of the works and to attend to the light, which may be placed in oscillating
cradles provided at the ends of the breakwater, so constructed as to present
the minimum of resistance to the wind and waves.
These floating breakwaters are intended to be placed in one or two lines,
which may be arranged in a circular, oval, triangular, oblong, half-moon, poly-
gonal, or a straight line, as may be required. The framing of the inner line of
breakwaters is to be closer than the framing of the outer line, and may be
close sheeted, if advisable. The inner line of breakwaters should be placed
at such distance from the outer line as to prevent the waves which have
passed over it recovering their velocity or power, which will become entirely
expended on the inner line of breakwaters; thereby securing smooth water in
the basin beyond, into which vessels will be admitted by apertures sufficiently
wide to afford easy access to it for the largest ships. The outer line of break-
water only is to be provided with the said inclines, and should it be deemed
requisite the two lines may be placed sufficiently near to allow of a platform
being placed between them; and such platform may be used as a promenade,
wharf, staging, or parapet, on which ordnance may be mounted for coast
defence. The said pontoons (without the suspended piling) may be provided
with framing, so as to carry an iron-plated guard, moored and connected by a
continuous chain, so as to form a boom for the defence of commercial or
other harbours.
Floating breakwaters constructed as herein-before described, may be built
with great facility in sections on land, and may be moored in position at any
time of the tide, or in any weather. They will be economical in construction,
and may readily be repaired.
In order that my said Invention may be fully understood, I will now
proceed to describe the same in connection with the Sheet of Drawings here-
unto annexed.
DESCRIPTION OF THE DRAWINGS.
Figure 1 is an external elevation and part section of a breakwater con-
structed according to my Invention; Figure 2 is a transverse section of the
same, and Figure 3 is a transverse section of a double breakwater, shewing

page_text: ;
pontoons and moorings, with a deck platform between them. Letter A shows
the elevation of a pontoon and framing, with incline plane in front; B is an
elevation without incline, showing pendant piles; C is a pontoon in section,
shewing buffers, connecting chain, and drums between pontoons; D is the end
of pontoon in elevation, shewing the friction bands for framing and mooring
chains (a) are the mooring chains or bands passing round the pontoons and
the rollers on the mooring blocks; (b) are blocks of granite; (c) are
pendant iron piles; (d) are elastic links to permit the rise and fall of the tide
without slack. Figure 4 is a section of an elastic link used to prevent slack
in the mooring cables, so as to compensate the rise and fall of the tide. It
consists of a wrought-iron caseing enclosing a packing of vulcanized india-
rubber at each end, passing through which is a piston link with a solid head,
working against the said india-rubber packing. Letter (a¹) is the india-rubber
packing, and (b) are piston links with solid heads.
Having now described and particularly ascertained the nature of the said
Invention, and the manner in which the same is or may be 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 variations may be made therefrom without deviating from the main
features of the 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, the use of floating breakwaters adapted for the
facile and economic formation of harbors of refuge and other such purposes
as herein-before described and illustrated.
In witness whereof, I, the said Bamfyeld Henri Francis Macnamara,
have hereunto set my hand and seal, this Thirty-first day of March, in
the year of our Lord One thousand eight hundred and sixty-one.
BAMFYELD HENRI FRANCIS MACNAMARA, C. E. (L.S.)
R. E. D.,
Great Yarmouth.
Witness,
GEORGE WOODWARD,
Southtown Barrks,
Great Yarmouth.
31. 3. 61.