IMPROVEMENTS IN TWIN-BOATS
Year: 1884

page_text: We, JAMES LINKLETER, of 60 Hotspur Street, Tynemouth, in the County of
Northumberland, Detaching-Gear Manufacturer and WILLIAM POPE MEARS, of
Prudhoe Terrace, Tynemouth in the County of Northumberland, Doctor in
Medicine do hereby declare the nature of our invention for IMPROVEMENTS IN
TWIN-BOATS, and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement:-
:-
Our Invention relates to certain improvements in Twin-Boats, Rafts or Buoys
used for the saving of life or other purposes, rendering them easily navigable
in any required direction and adaptable for certain special uses to be hereinafter
described.
These Improvements consist in the (a) form, (b) construction (c) connection and
(d) relative position of the two tubes and render the complete structure available
according to size as (1) a Life-Raft (2) a portable Life-Boat or (3) Surf-boat for
ship or shore use, (4) an Exploring-Boat for shallow rivers or (5) a Sledge for arctic
work, (6) a life-saving Seat-raft or Sledge for lakes used for swimming or skating
and lastly in the smallest form as a (7) Life-buoy.
The special points of the Invention and its adaptations as mentioned above
may be better understood from the following description & the accompanying
drawings.
(a) FORM. Each Tube is throughout square or quadrangular on section and
floats on the angle (See Figure I. which represents a cross section of the Raft
showing also the mast in position.)-Thus a double keel (Fig. 1. a. a.) is provided
giving much lateral with little longitudinal resistance & preventing leeway whilst
allowing great headway when under sail-Again the shape gives greater stability
than any other form with rapidly increasing displacement & buoyancy, Thus whilst
the Boat or Raft carrying the ordinary crew and gear has a draught of water equal
to about half the distance from the gunwale (a¹) to the keel (a) it will carry three
times as much more weight as that of itself, the crew & gear combined before it
sinks to the level of the gunwale,-When taking the water from a ship's deck or
davits or on clearing a sea the Boat or Raft in consequence of its wedge-like form
falls easily into the water without jerk or strain or risk of staving-As the upper
and lower parts are similar it follows that the Boat or Raft floats equally well &
has an equal carrying power even if it takes the water in an inverted position.
•

page_text: By bringing in the gunwales of each tube to a stem and sternpost (Fig. II. sm.
and pn.) a good lift forward is provided with a clear run aft.-Again the force of a
sea or squall striking the Boat or Raft abeam falls upon an angle or upon sloping
and oblique surfaces & exerts but a fraction of its effect on the boat itself. In a
similar way in meeting a bowing sea end on the upper edges of the tubes cut
themselves clear of the water at once. The upper edges and upper and inner
surfaces of the tubes form an efficient bulwark.-Sledge-runners are easily fitted
onto the keels when the Raft is to be used on ice. In the case of the Life-Buoy
the form enables it to be easily propelled by a swimmer in any required direction.
(b) CONSTRUCTION. The plan of construction of the tubes is shown in Figs. I
& II, Fig. I representing a cross section of the complete tube, and Fig. II. the
longitudinal framework of the tube and the bulkheads.-The framework of each
tube consists of a certain number of square or quadrangular water-tight bulkheads
(b. b. b. b. Fig. II) supporting on their angles longitudinal rods or bands (a, a¹,
a, a, Figs. I & II) of which the lowermost (a) forms the keelson, the lateral
(a, a) the gunwales of the tube and the uppermost (a") the gunwale of the
Boat or Raft. These rods or bands in turn steady the bulkheads, aid in supporting
the thwarts & connecting parts and are secured together at their extremities to
form the bows and stern. In the larger Boats or Rafts extra support is afforded to
the skin of the tube by intermediate lighter rods or bands running fore & aft more
or less parallel to the main rods. (See Figs. I & II c. c. c. c) The tube is covered
in by some flexible or resilient.material (such as single canvas or double canvas
with a layer of cork or other material interposed or steel) and is divided into
water-tight compartments by the close apposition of this skin to the edges of the
bulkheads. By making the framework and skin of flexible or resilient substance
as cane & canvas the Raft or Boat-tubes are rendered practically unstaveable, even
if one or more of the compartments are pierced the boat will still support its
crew. The exact nature of the material will necessarily depend on the purpose to
which the Boat, Raft or Buoy is to be put.-The bulkheads not only form solid &
firm supports for the framework but largely aid also in sustaining the battens and
connecting parts. Hence as shown by arrows in Fig. I. the force of a concussion
(which in the great majority of cases would fall on one of the projecting angles, as
in the case of a blow from the side of a lurching ship during the lowering of the
Boat or Raft,) is dispersed in all directions instead of exerting itself solely at the
point of impact.—In all these respects they act equally well when made to revolve
in the manner to be presently pointed out. The mode of construction of the tubes
offers great advantages in regard to the connecting and binding together of the
tubes. Provisions, water etc. can be stored in cases fitted into the angles between
the upper thwarts and upper and inner surfaces of the tubes without the air-space
of the tubes being encroached upon. (see Fig. I. c. e.)
C CONNECTION. The tubes are connected together by two sets of thwarts or
battens upper (Figs. I & III f) & lower (Figs. I & III. g), These thwarts or
battens are fixed to the tubes immoveably or by hinged and moveable joints
according to the purpose for which the Boat or Raft is intended. The upper series
form seats the lower footboards or stretchers, The intervals between the lower
thwarts or battens are closed by netting or grating, (see Fig. III) which forms the
floor. In the case of the Life-buoys only the lower battens are fitted & the
intervals between them are not closed by netting or otherwise. The connection of
the battens etc. with the framework and bulkheads of the tubes gives great rigidity,
strength & power of resistance to any oblique strain. A great advantage of this
mode of connection is the security which is afforded by it for the stepping of the
mast or masts midway between the tubes (see Figs. I & III. m.) The mast is
stepped in a socket in the lower thwart and in passing up through the upper
thwart is steadied in a tabernacle. (n.)-The connecting thwarts or battens leave
between them a series of compartments in which the crew are secure under
ordinary circumstances from risk of being washed overboard, the more so as the
netting or grating prevents any accumulation of water in the boat itself.-In the

page_text: case of the Life-buoys the man supported can come up between or support himself
on the batten's far more effectively than he could with the ordinary form of buoy,
and two persons in the water at the same time can keep clear of one another,
a very important matter in regard to which this form of buoy offers great
advantages. The buoy without any alteration can be used as a Stretcher.
d RELATIVE POSITION.-When the joints of the thwarts with the tubes are fixed
the tubes are straight and parallel and lie in a horizontal plane angle to angle (see
Fig. I & III), but when the joints are moveable or hinged the tubes may be folded
over for convenience of storage or may be collapsed and laid flat one on the other as
shown later on in this description and the accompanying diagrams.-When the Boat
or Raft is ready for use the relative position of the tubes is such, that if the Boat
or Raft broach to when running before a sea or be caught abeam by a breaking sea
it follows that as the weather tube is elevated the lee tube presents more and more
a flat bearing surface to the water & will thus allow of the Boat or Raft sliding
away before the sea instead of being tripped. The Boat can be capsized only by a
bowing sea striking it abeam of sufficient size to throw it over bodily. The chief
advantage of the relative position of the tubes comes out in connection with the
use of the Boat or Raft as a Seat whether on board ship or elsewhere.
When thus used the Boat or Raft may be placed as shown in Figs. IV at an
angle of 45° resting against the bulwarks of the ship, the sides of a deck-house or
other supporting structure. In this position the lower tube (o) forms the seat, the
net or connecting parts a back-rest & the upper tube (p) a head rest. The Boat
or Raft if placed in this position under davits will not occupy so much space as a
boat of the same length or carrying capacity & is all ready for swinging out.
oars, spars etc. are stowed between the two sets of thwarts. (z. z Fig. IV).
The
The smaller sized Boats or Rafts are rendered capable of stowage in a small
space by the further arrangements shown in Figs. IX-XV.-Figs. IX represents
a view from above of the fore end of the fully opened Boat or Raft with the
foremost bulkheads (1. 1.) exposed. Fig. XI shows a cross section of the same
parts. These like all the other bulkheads in each tube are connected at their inner
angles each by a metal bar (2) with the corresponding lower thwarts (3).—The
bar or rod passing through a tightly fitting tube or ring on the innermost rod of
the framework. At their outermost angles (21) the bulkheads each turn upon a
pivot fixed to the outermost rod of the framework, near either end of each of the
lower thwarts is fixed a short lever (4) directed upwards parallel to the vertical
plane of the bulkheads. At the bows & stern the rods of the framework are
brought into stem and stern-post of rope (Fig. XIV. 5.) which in the opened-out
position of the Boat are straight & vertical (see Fig. XIV dotted lines) The upper
thwarts are removeable. They are retained in position in the opened-out Raft or
Boat by pins (6. 6. Figs. IX.-XV.) passing up through slots near their extremities
(7. 7. Figs. XIII & XV) from the uppermost rods of the framework & intermediately
by the ends of the, levers (4. 4.) connected with the lower thwarts which levers
they in turn steady & support. Each lower thwart is jointed at its centre (8),
When the boat is to be closed up the heads of the pins and levers passing through
the upper thwarts are turned over the slots (Fig. XIII dotted lines,), the upper
thwarts are lifted off and the levers are turned forward so as to rotate the lower
thwarts through an angle of 90°. thus bringing the surfaces of the bulkheads into
a horizontal plane. As the bulkheads rotate the uppermost & lowermost rods of
the framework fall together separated only by the thickness of the bulkheads,
(see Fig. XII & Fig. XIV, the former indicating the appearance of the tube on
transverse section, the latter on longitudinal side view. The canvas skin
(Figs. X & XII (9) & rope stem and sternpost are slackened & doubled in so that
each tube becomes nearly flat. The upper thwarts are then placed on one of the
tubes & retained by passing the pins on the uppermost rod through them, Lastly
the other tube is folded over onto the first named by bending the joints (8) in the
centre of the lower thwarts. Thus folded the boat would occupy under a quarter
of the cubical space taken up by it when opened out.

page_text: The form suitable-for-a-Life-buoy-is-shown in Fig-VII-In order to give as
much supporting power as possible the stem and stern-posts are made straight and
The breadth is
vertical & the gunwales are brought in sharply to them.
under 2 ft. and the length about 4 or 5 feet, & the sides of the tubes 4 or 5
inches broad. The weight of the buoy (constructed of light wood & canvas on
the same general principles as in the case of the larger tubes) is not so much as
that of an ordinary buoy. & its supporting power is greater. It can be thrown
with equal facility & in the water gives a very convenient hold to the swimmer.
It can also be readily steered.
Having now particularly described and ascertained the nature of our said
Invention and in what manner the same is to be performed we declare that what
we claim is :-
(1) The combination for the purpose of making a Boat, Raft or Buoy of
two parallel tubes, square or quadrangular on section floating on the angle,
substantially as described & shown in this Specification (Figs. I. II & III.)
(2) The construction of each tube by four chief longitudinal rods or bands, one
forming the keel, two the gunwales of the tube & the fourth the gunwale of the
Boat, Raft or Buoy, substantially as described and shown in this Specification
(Figs. I & II).
(3) The mode of revolving the bulkheads so as to allow the tube to collapse,
substantially as described & shown in this Specification. (Figs. IX to XII & XIV).
(4) The mode of connecting the two tubes by upper & lower th warts or battens,
forming seats and footboards respectively, substantially as shown and described in
this Specification. (Figs. I & III).
(5) The relative position of the two tubes so that when the Boat or Raft is
placed at an angle as in Fig. IV. one tube forms the seat and the other with the
connecting parts a back or head-rest, substantially as shown & described in this
Specification.
(6) The mode of collapsing & folding the tubes for convenience of storage
substantially as shown & described in this Specification (Figs. IX-XV).
JAMES LINKLETER.
W. P. MEARS.