Improvements in Sheet-metal Boats.
Year: 1890

page_text: Date of Application, 15th Apr., 1890
Complete Specification Left, 14th Jan., 1891-Accepted, 14th Feb., 1891
PROVISIONAL SPECIFICATION.
Improvements in Sheet-metal Boats.
I, CHARLES HENDERSON, of 9 York Street, Glasgow, Lanarkshire, Engineer,
do hereby declare the nature of my invention to be as follows:-
This invention has reference to and comprises improvements in the construction of
sheet-steel or other sheet-metal boats, specially suited for life-boats, ship and other
boats, all with the purpose and object of making them lighter, stronger, and more
safe and durable than such boats have been as heretofore constructed.
The improvements consist all as follows:-In making the shell of the boat out of
sheet-steel, iron, or other sheet-metal in transverse curved plates rolled or creased
in sections to suit required length of boat, and of a length reaching from the one
gunwale, or stringer under gunwale, to the other over the keel; or it might be two
curved plates half that length, reaching from the keel up to the gunwale or stringer
under gunwale ou each side, with flanges capped or creased up at each end of the
plate while bending them to the curve of the boat, or afterwards, these flanges being
made deep enough to form or assist in forming the transverse frames of the boat as
hereinafter described. When each transverse section of the shell of the boat is
thus made of one plate, the rib or section to form keel may be creased out of the
shell plates, or it might be riveted on to the upper side of the keel, to the two
flanges of a T-iron keel, on each side of the centre line or rib, or this keel and
centre longitudinal rib might be of a V or U channel shape with side flanges for
riveting the plate to, on each side of the centre line; or the keel, stem and stern
posts may be of wood, or wood and metal combined and bolted to shell plates; but
when each section is made of two plates, the plates at the keel would be flanged so
as to rivet to an ordinary edge bar keel; or the two thicknesses of plates may be
inserted into a split tube or other hollow section and securely fastened; in either
case, however, the transverse end flanges of the plates would be capped upwards
and inwards, so as to be riveted to each other as close flanged joints, strengthened
by an edge or inverted U (n) bar on the inner side of each flange, or a single bar
between the flanges, or one on each side of flanges, deep enough to form the
frames or ribs of the boat, and having the rivets close enough to form close
joints. Or otherwise, in place of riveting these flanges, they might be gripped in
the open split joint edge of a split tube of round, oval, astragal, or other shape
by folding over the flanges within the edges of these tubes, which might be of
various sections, and compressing them close at the overlapping parts as a joint,
leaving the hollow or overlapping parts of these tubes strong enough to form the
ribs of the boat of whatever section they are constructed at the ends of each
transverse streak of plates, making outside flush and tight with solder or cement.
Or otherwise the tubular frames may be secured to the flanges of the shell plates
by forming slots on inside edge of hollow frame into which short projections or
tails on the transverse flanges would be inserted and turned over or riveted on the
inside to the frames to shell plates. Each of these transverse streaks of plates
might be strengthened longitudinally by embossing them in ridged corrugations
outwards or inwards in the flat parts between the flanges, with rounded or egg
shaped ends to cause the least possible friction of the water on the outer surface.
Another improvement consists in strengthening the boat longitudinally by a
sheet metal corrugated or hollow tubular keelson of any convenient section to give
lightness and strength, riveted to the said plates between the flanges to the keel
below, or kneed or checked over the said new flanged ribs throughout the whole
length.
1
By a further improvement the gunwales or stringers would be made of sheet

page_text: metal tubes of round, oval, square, or other section, and either be gripped in the
open joints of the said tubes, or be screwed or riveted to the upper edges of the
side plates at the gunwale and upper ends of the frame flanges, or secured to
frames and shell plates by means of brackets or knees. And by a further improve-
ment the thwarts would also be made of sheet steel or other metal, with their side
edges capped down as flanges, and have the flat surface indented or corrugated, all
to give them strength athwartship, and have knees riveted to them and to the said
flanged frames or the sheet sides of the plates; or the ends of the thwart plates
might have checks cut out of them to receive the flanged frames and be bent up
as knees to secure the thwarts and tie the upper edge or gunwale of the boat
athwartship; or the thwarts may be made of a box shape of metal or wood, or
wood and metal combined, made air-tight to form part of buoyancy, and these box
thwarts if made of metal may have thin edges turned in and connected together by
a split tube covering and securing the flanges inside, and compressed to make a
tight joint. For life-boats, air-tight boxes would be ranged longitudinally on each
side under the thwarts and gunwales close up to the side plates of the boat secured
to and between the flanged frames and plates, or air-tight chambers may be
constructed on each side divided into sections by means of transverse and longi-
tudinal bulkheads or divisions, the shell of boat forming the outside of air tight
chambers, all to give safe floatation and buoyancy. In some cases these longitudinal
air-tight chambers might be made narrow enough on the top only to form fore and
aft seats; in which case extra buoyancy would be given to the upper parts of the
boats by a D shaped longitudinal air-tight chamber dished up out of one plate in
the width and running from stem to stern on the outside and under the gunwale,
secured at its lower and upper flanges to the plate walls of the boats, which would
give additional buoyancy and greater strength to the upper walls or gunwale part
of the boat. In some cases this additional buoyancy outside might be given by
creasing the shell plates of the boat outwards at the upper part, and riveting the
two flanged edges of a longitudinal knee plate at the gunwale and down near the
thwarts of the wall plates, which would also give the said buoyancy and great
strength above the thwarts.
A further improvement consists in making the transverse frames and longitudinal
stringers of any form of sheet steel or other sheet metal for boats, whether made of
lap riveted joints or otherwise, of split or welded hollow tubes of round, oval, or
other section, which may be made of unequal thickness of metal where strength is
required, secured by screws or rivets to the shell plates of the boat, or to the keel
and gunwales, and where the stringers cross the frames they might be creased into
each other, and secured in this way by screws, rivets or glands. The top sides of
the thwarts of boats may be made of wood or metal, or wood and metal combined, or
they may be made of metal tubes; and instead of making the platforms or floors of
wood as usual, they may be constructed of sheet metal suitably corrugated and
attached to frames or cross floors. In order to give additional buoyancy without
reducing the internal accommodation for passengers, the bottom may be made
double with an air-tight span between the shell plates and inside platform or floor,
divided into longitudinal and transverse compartments, and made corrugated on
the upper surface for strength. Instead of having separate air-tight chambers at
each end of boats, additional buoyancy may be given by means of air-tight
transverse bulkheads and top cover of metal secured to gunwale or stringer and
bulkhead, preferably under the thwarts. Or otherwise, an equivalent central
longitudinal air-tight compartment might be formed over the keelson and under
the thwarts. And in some cases the boat may be made in two longitudinal equally
divided parts, and secured together at these central longitudinal division plates or
air-tight compartments at the keel and keelson and along the top edge.
"
Dated the 14th April 1890.

page_text: COMPLETE SPECIFICATION.
Improvements in Sheet-metal Boats.
I, CHARLES HENDERSON, of 9, York Street, Glasgow, Lanarkshire, Engineer,
do hereby declare the nature of my invention, and in what manner the same is to
be performed to be particularly described and ascertained in and by the following
statement in writing, reference being had to the accompanying sheet of drawings,
and to the letters and figures marked thereon, that is to say :-
My invention has reference to and comprises improvements in the construction
of sheet steel or other sheet-metal boats, specially suited for life-boats, and ship
and other boats, all with the purpose and object of making them lighter, stronger,
and more safe and durable than such boats have been as heretofore constructed.
And in order that my said invention, and the manner of performing or carrying
the same into effect or practice may be properly understood, I have hereunto
appended an explanatory sheet of drawings in which the same reference letters are
used to indicate corresponding parts in all the figures where shown.
Figures 1 and 2 are a sectional elevation and a plan respectively of the longitudinal
half of a boat as constructed in accordance with my improvements.
Figures 3 and 4 show vertical sections of the one transverse half of the boat as
constructed with two different forms of keels and keelsons.
And the other Figures 5 to 12 show detail views of the improvements which will
be hereinafter referred to.
Referring to these drawings:-The improvements consist all as follows:-In
making the outer shell A of the boat out of sheet-steel, iron or other sheet-metal
in transverse curved plates creased or rolled in sections longitudinally or parts A, A',
each the full width and shape of the boat in transverse section to suit the required
sections and length of boat, and each section of a length reaching from the one
gunwale A, or stringer A" under gunwale, to the other over or past the keel B, as
shown in Figures 3 to 6; or it might be two curved plates half that length, reaching
from the keel B up to the gunwale A' or stringer A" under gunwale on each side,
with flanges a capped or creased up at each end of the plates A, A', while bending
them to the curve of the boat, or afterwards, these Hanges a being made deep
enough to form or assist in forming the transverse frames of the boat as hereinafter
described. When each transverse section A, A', of the shell of the boat is thus
made of one plate, the rib or section to form the keel B may be creased out of the
shell plates, as shown in Figure 4; or the plate might pass right across between
the keel B and the keelson B', as shown in Figure 3, or might be riveted on to the
upper side of the top flange of a T-iron keel, on each side of the centre line or
rib B", as shown in Figure 5; or this keel and centre longitudinal rib might be of
a Vor U channel shape with side flanges B2 for riveting the plate to, on each side
of the centre line, as shown in Figure 6; or the keel, stem and stern posts may be
of wood, as shown in Figure 1, or of wood and metal combined and bolted to shell
plates; but when each section A, A1, is made of two plates, the plates at the keel B
might be flanged so as to rivet to an ordinary edge bar keel B³, as shown in
Figure 7; in either case, however, the transverse end flanges a of the plates A, A',
would be capped upwards and inwards, so as to be riveted to each other, as shown
in Figure 8, as close flanged joints, or they might be welded electrically or other-
wise and if necessary strengthened by an edge bar between the flanges a, as shown
in Figure 9, or it may be an inverted U (n) or channel bar on the inner side of
each flange a, as shown in Figure 10, or a single bar on each side of the flanges a,
in either case being deep enough to form the frames or ribs of the boat, and having
the rivets close enough to form close joints. Or otherwise, in place of riveting
these flanges a, they might be gripped in the open split joint edge of a split tube 2
of round, oval, astragal, or other shape by folding over the flanges a' Figure 11,
within the edges of these tubes 2, which might be of various sections, and com-
pressing them close at the overlapping parts as a joint, leaving the hollow or. inner

page_text: overlapping projecting part of these tubes 62 strong enough to form the ribs of the
boat of whatever section they are constructed at the end flanges a of each transverse
streak of plates, making outside flush and tight with solder or cement, and this
form of joint may also be used as a longitudinal keel B, when the plates A, A', are
jointed at the keel, the tube 2 forming the keel outside. These longitudinal
sections A, A¹, may be made of various lengths between the flanges especially
the intermediate or parallel midship lengths, which lend themselves to making the
boats of various lengths by introducing only different lengths of sections at the
centre. Each of these transverse streaks or sections of plates A, A', might be
strengthened longitudinally by embossing them in ridged corrugations outwards or
inwards in the flat parts between the flanges a with rounded or egg shaped ends to
stiffen the plates and cause the least possible friction of the water on the outer
surface; or additional strength may be given to the plates by fitting independent
wood, sheet metal, or tubular ribs c at intervals between the flanges a on the inside
and secured to plating.
Another improvement consists in strengthening the boat longitudinally by a
wood keelson B', shown in Figures 1 to 4 checked over the flanges a or it might be
a sheet metal corrugated or hollow tubular keelson B¹, indicated in dotted lines
at B Figure 7, similarly fitted down to the shell A or keel B below the frames, of any
convenient section to give lightness and strength, riveted to the said plates A, A',
between the flanges a to the keel B below, or kneed or checked over the said new
flanged ribs throughout the whole length.
As shown in these drawings, seats Ď are shown as formed of wood all round the
walls of the boat, some distance below the gunwale A2 and over the stringers All
with small deck parts D', at the bow and stern as a continuation of the side seats,
and with strong thwarts D2 at intervals to strengthen the sides of the boat and give
seating accommodation for the passengers. And air-tight compartments E of sheet-
steel or other metal are inserted under the seats D, boarded in at E' all round
between the several sections A' a, and one E2 at the bow and stern, also boarded in
at E under the deck part D'. The seats D and thwarts D2 are secured by iron
knees at C; and floor or footboards d would be laid at intervals, with spaces between
them over the joint flanges a and frames c; and a foot platform would be formed
at d'over these in the bow and stern end compartments all being shown as formed
of wood in Figures 1 and 2.
Instead of making the gunwales A2 or stringers below these at A" on the inside,
of wood, as shown in Figures 3 and 4, by a further improvement these may be made
of sheet metal tubes of round, oval, square, or other section, as shown applied to the
gunwale at A³ in Figure 12, and either be gripped in the open joints of the sail
tube A³, or be screwed or riveted to the upper edges of the side plates A, A1, at
the gunwale and upper ends of the frame flanges, or be secured to frames and shell
plates by means of knees or brackets C¹. For life-boats the air-tight boxes E
would be ranged longitudinally on each side under the side seats D and thwarts D²
close up to the side plates of the boat, secured to and between the flanges a a of
each sectional part A A¹ of the shell plates, all to give safe floatation and
buoyancy.
Instead of making the thwarts of wood as shown in these drawings they may be
made of sheet-steel with strengthening edges flanged downwards or they may be
corrugated lengthwise of the thwarts.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what 1
claim is-
First. The construction, or arrangement and combination of the parts of sheet-
metal boats formed of transverse curved plates in sections longitudinally and flanged
and secured together at their longitudinal ends, all substantially as and in the
manner herein described, in reference to and shown in the accompanying
Crawings.

page_text: Second. The constructing of sheet-metal boats in sections longitudinally from
transverse curved plates, substantially as and in the manner herein described in
reference to and by way of application shown in the accompanying drawings.
Third. The constructing of sheet-metal boats in sections longitudinally from
transverse curved plates secured together by flanges and split tubes, or joint pieces
to form the frames of the boat, substantially as and in the manner herein described
in reference to and shown in the accompanying drawings.
Fourth. In sheet-metal boats, the constructing of them in sections longitudinally
from transverse curved plates, in combination with a hollow tubular or corrugated
keel or keelson, substantially as herein described, in reference to and shown in the
accompanying drawings.
Fifth. In sheet-metal boats, the constructing of them in sections longitudinally
from transverse curved plates, and having the gunwales, stringers, or frames formed
of tubular metal, substantially as herein described, in reference to and shown in the
accompanying drawings.
Dated the 10th Lana 1001
W. R. M. THOMSON & Co.,
96, Buchanan Street, Glasgow, Agents.