Note: Descriptions are shown in the official language in which they were submitted.
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MARINE ESCAPE SYSTEMS.
The present invention relates to marine escape systems
for use in the evacuation of passengers and crew from a
ship in an emergency.
In an inflatable escape slide system hitherto proposed,
an inflatable slide and platform assembly is stowed
uninflated at a stowage position on the deck of a ship
and is deployable from the stowage position to a deployed
disposition in which the inflated platform floats on the
water with the inflated slide extending from the stowage
position downwardly to the platform to provide an
inclined descent path for evacuees from the ship.
Uninflated liferafts housed in containers are discharged
from the deck of the ship into the water and members of
the ship's crew slide down the slide to the boarding
platform and pull the liferafts, still in their
containers, by marshalling lines to the boarding
platform. The crew members then actuate inflation
apparatus within the containers by pulling hard on the
marshalling lines, whereupon the liferafts inflate out of
their containers.
The marine escape slide system hereinbefore described has
been found suitable for use on large vessels in place of
or in addition to davit launched lifeboats. For such
vessels, weight of the system is no serious penalty and
the vessels usually have adequate deck space for location
of several escape systems at spaced escape positions
long each side of the vessel. The slide and platform
assembly is stowed uninflated in a permanent housing at
each escape position, with banks of liferaft containers
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mounted on inclined racks on each side of the escape
position for discharge into the water during or following
deployment of the escape slide and platform. Evacuees
assemble at the escape positions at which the escape
slide and platform are stowed and from which they are
deployed.
For vessels having moderate freeboard, for example
between 3 and 6 metres, especially such vessels carrying
passengers, it is not convenient to fit davit launched
liferafts due to the weight penalty and space
requirements. Furthermore, on such vessels, the marine
escape slide systems hitherto proposed are difficult to
fit in the same location as the emergency exits due to
lack of space. For such vessels, engaged for example in
ferrying passengers over short distances, provision is
usually made simply for the deployment of inflatable
liferafts in an emergency, leaving the evacuees to don
lifejackets and either to climb down scrambling nets
dropped from the side of the vessel or to jump into the
water and then climb aboard a liferaft brought alongside.
In emergencies requiring action of this kind, the more
fearful passengers are reluctant either to use scrambling
nets or to jump into the water and make their way to the
liferaft, which may be some distance from the point at
which they enter the water. It has indeed been found
that passengers evacuating a vessel having freeboard of 3
to 6 metres find themselves too high to jump from the
deck either into the water or into a waiting liferaft.
It has furthermore been found that in the marine escape
slide system hereinbefore referred to, where the upper
end of the slide is secured to the permanent housing in a
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disposition in which it extends outwardly in a vertical
plane at right angles to the side of the ship, buckliny
or twisting of the slide can occur when the floating
platform ls subjected to adverse strong currents or
wlnds. rrhe use of restralning guy wires is found to be
inconvenient and it has therefore been considered
desirable to dispense with them and to arrange for the
platform and slide to be attached to the side of the ship
in such a manner as to permit pivoting of the floating
platform and inflated slide assembly so that it can take
up a position in which the slide extends outwardly at an
acute angle to the side of the ship. Mechanisms for
achieving this end would, however, in escape systems
hitherto proposed, encumber the permanent housing at the
escape position and be of generally complex and rugged
construction.
It is an object of the present invention to provide an
inflatable marine escape unit which can be used on
vessels of moderate freeboard, say from 3 to 6 metres
without the drawbacks of the marine escape slide system
hitherto proposed for use with large vessels, while
avoiding the disadvantages experienced by evacuees in the
methods of evacuation hitherto employed on vessels of
moderate freeboard.
According to a first aspect of the present invention
there is provided an inflatable marine escape unit for
use by evacuees disembarking from a vessel, wherein an
inflatable liferaft and an inflatable slide are arranged
to be discharged together in collapsed conditions from
the vessel for deployment on the water with the inflated
liferaft floating on the water and the inflated slide
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connected at one end thereto and extending therefrom~
wherein the slide comprises a main body portion and a
head portion located at a boarding end of the slide
remote from the liferaft, wherein the head portion
includes a first inflatable element for attachment to the
vessel and a second inflatable element attached to the
main body portion of the slide and arranged for pivotal
movement relative to the first inflatable element about a
vertical or generally vertical pivotal axis, whereby the
liferaft and the main body portion of the slide can turn
about the pivotal axis and take up any one of a plurality
of floating dispositions relative to the vessel.
In a preferred embodiment of the invention, the first
lS inflatable element is arranged to be supportable in a
depending position from the side of the vessel at deck
level and to bear against the side of the vessel and the
second inflatable element is mounted on the first
inflatable element for turning movement thereon about the
pivotal axis. The second inflatable element is held
against the first inflatable element by a flexible tie
which extends between the two elements along the pivotal
axis and which holds them together while allowing
relative pivotal movement of them about the pivotal axis
by the twisting of the tie. The first inflatable element
is provided with releasable attachment means for
attaching it to the side of the vessel at an exit
position and for supporting it in its depending position.
In a first of the embodiments of the invention
hereinafter to be described, the first inflatable element
takes the form of an inflatable cushion folded back upon
itself to form upper and lower limbs, the upper limb is
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attached at its end to the vessel at deck level and
carries the second inflatable element and the lower limb
takes up a position in which its end bea-s against the
side of the vessel.
In an alternative embodiment of the invention hereinafter
to be described, the first inflatable element is in the
form of an inflatable ball and the second inflatable
element is mounted on the ball in such disposition that
the pivotal axis about which it turns coincides with the
central vertical axis of the ball.
The second inflatable element preferably comprises an
inflatable annular tube which rests upon an upper surface
of the first inflatable element.
In yet another embodiment of the invention the first
inflatable element is in the form of an inflatable
cylindrical body so suspended in use as to rest against
the side of the vessel at deck level with its axis
vertically arranged. The upper end of the cylindrical
body is closed by a frusto-conical end piece which is
arranged with its axis coincident with the axis of the
cylinder and its small end uppermost and the inflatable
annular tube so fits over the end piece as to rest on the
frusto-conical surface and is secured to the upper
smaller end of the end piece by the tie which permits
pivoting movement of the ring about the vertical axis of
the cylinder.
In the preferred embodiment of the invention the slide is
provided at the boarding end of the slide with a
marshalling line which extends from the boarding end of
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the slide for connection to the vessel and which can be
used to bring the boarding end of the slide to an exit
position on the vessel.
The liferaft and slide are, in the preferred embodiment
of the invention, housed in their collapsed conditions in
a container and are arranged to be discharged from the
vessel in the container and to be released from the
container after discharge for deployment on the water.
According to a second aspect of the present invention,
there is provided a method of deploying at an exit
position on a vessel an inflatable marine escape unit
according to the first aspect of the invention,
comprising the steps of stowing the liferaft and slide in
collapsed conditions on the vessel at a stowage position
spaced from the exit position with one end of the slide
connected to the liferaft and with a marshalling line
connected at one end to the vessel and at the other end
to the boarding end of the slide, discharging from the
vessel the liferaft and slide together in their collapsed
condition whereby they take up a disposition in which the
liferaft is inflated and floating on the water with the
slide connected thereto and with the marshalling line
extending from the boarding end of the slide to the
vessel thereby to hold the liferaft and slide captive to
the vessel, and bringing by means of the marshalliny line
the boarding end of the slide to the exit position on the
vessel during or after inflation of the slide or before
inflation of the slide and subsequently inflating the
slide.
Preferably, the method according to the second aspect of
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the invention includes the s-tep of inflating the liferaft
after its descent in a collapsed condition on to the
water. The uninflated slide is then withdrawn from its
collapsed condition and extended from the inflated
liferaft by pulling on the marshalling line and is then
inflated. Inflation of the slide is preferably commenced
during the step of bringing the boarding end of the slide
to the exit position.
Some embodiments of the invention will now be described
by way of example with reference to the accompanying
drawings in which:-
Fig. l is a schematic plan view of part of a ship of
moderate freeboard fitted with two inflatable marineescape units according to the first aspect of the
invention;
Figs. 2 to 6 are schematic plan views corresponding to
the view shown in Fig. l and illustrating successive
steps in the method of deployment of the inflatable
marine escape units in accordance with the second aspect
of the invention;
Fig. 7 is a schematic plan view of one of the marine
escape units shown in Figs. l to 6 deployed and
positioned at the side of the ship and corresponding to a
deployed unit at the left-hand side of Fig. 6;
Fig. 8 is a schematic sectional side elevation of the
marine escape unit shown in Fig. 7 taken on the line
VIII-VIII in Fig. 7;
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Fig, 9 is a schematic sectional side elevation of the
upper end of the slide shown in Fig. 7, illustrating the
pivotal head of the slide by which the slide is secured
to the ship; and
Fig. lO is a schematic side elevation of the upper end of
a slide of a marine escape unit according to another
embodiment of the invention, illustrating an alternative
form of pivotal head.
Referring to Fig. l, a ship ll having a freeboard of 3
metres includes a deck 12 provided with deck rails 13,
parts of which are withdrawn to provide exit positions 1
and 15 for use by passengers and crew during normal
embarkation and disembarkation and when evacuating the
ship in an emergency. At a stowage position 16
intermediate the exit positions 14 and 15 there is
arranged an inclined rack lO supporting inflatable marine
escape units 17 and 18, which are held in place on the
rack lO by straps (not shown) prov-ided with quick release
buckles.
Each of the escape units 17 and 18 comprises a container
formed as a cylindrical shell closed by hemispherical
ends and housing in a deflated and packed condition an
inflatable liferaft and an inflatable slide for discharge
into the water together in the container. The container
is subdivided into two generally equal longitudinally
extending separable half-shells which are held together
in known manner against separation by bands which are so
weakened locally as to break on inflation of the liferaft
within the container and allow separation of the two
half shells under the action of the inflating liferaft.
g
One end of the slide is releasably connected to the
liferaft while the other end (the boarding end) is
provided with a flexible marshalling line 19 which
extends from the boarding end of the slide through an
opening in the end of the container to a detachable slide
ring 20 carried on a guide rail 21. The two guide rails
21 illustrated in Fig. 1 extend along the deck from the
stowage position 16 to the exit positions 14 and 15.
In an emergency, the escape units 17 and 18 are released
from the inclined rack 16 and roll under their own weight
over the side of the ship 11 and discharge into the wa-ter
as illustrated in Fig. 2 of the drawings, the marshalling
lines 19 being of sufficient length or being paid out
from the containers 17 and 18 by an amount sufficient to
allow the containers 17 and 18 to take up floating
dispositions on the water, while being held captive by
the marshalling lines 19.
Each of the containers 17 and 18 houses high pressure air
or gas inflation cylinders for inflating the liferaft,
and inflation of the liferaft is carried out either
automatically upon the container coming in to contact
with water or manually by a hard pull on the marshalling
line 19 or a supplementary line (not shown). Inflation
of the liferaft within the container is thus commenced
and as the liferaft inflates it tends to force the two
half-shells of the container apart. When the force is
sufficiently great the retaining bands break at the
points of weakness, the two half-shells then separating
to allow the liferaft to complete its inflation and
deployment in a floating disposition on the water as
illustrated in Fig. 4 of the drawings.
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The liferaft employed in the present embodiment of the
invention is shown schematically in Fig. 4 and indicated
by the reference numeral 22. It is of circular planform
and is provided with a canopy 23 having four openings 24
for use by survivors in gaining access to or exit from
the liferaft. The liferaft 22 in the present embodiment
of the invention has a capacity to take up to a maximum
of 42 persons, has a diameter of the order of 18 ft.
(5.48 m), has a height of the order of 6 ft. (1.82 m) and
is constructed from two superposed peripheral buoyancy
tubes, each having a diameter of the order of 16 in.
(40.6 cm).
At the entrance to one of the openings 24 of each of the
liferafts 22 there is stowed within the liferaft an
uninflated and folded slide 25 provided with its own high
pressure gas or air inflation cylinder. One end of the
slide is detachably secured to the liferaft 22 at the
opening 24, while the other end has connected to it the
marshalling line 19. In addition, the marshalling line
19, or a supplementary line, is connected to the
inflation cylinder for the slide and serves to open the
cylinder for inflation of the slide when given a hard
pull .
In a preferred method of deployment, when the liferaft 22
has become fully inflated, the marshalling line 19 is
pulled to withdraw the boarding end of the slide 25 from
its location at the opening 24 of the liferaft 22 and
extend the slide 25 in its uninflated condition. With
the uninflated slide 25 extended as illustrated at the
left-hand side of Fig. 5, the marshalling line 19 is
employed to bring the boarding end of the slide 25 to the
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exit posi~ion 14. During positioning of the boarding end
of the slide 25 at the exit position 14~ inflation of the
slide 25 is commenced so that the slide is fully inflated
when its boarding end is secured at the exit position 14,
as hereinafter to be described with reference to Figs. 7,
8 and 9 and as illustrated at the left-hand side of Fig.
6.
In an alternative method of deployment the marshalling
line 19 or a supplementary line is given a hard pull
while the liferaft 22 with the uninflated slide 25 is
still in the region of the stowage position 16, causing
the slide to inflate away from the liferaft 22 as
illustrated at the right-hand side of Fig. 5, and become
fully inflated while the liferaft 22 and slide 25 are
still in the location of the stowage position 16. The
liferaft 22 and the inflated slide 25 are then moved by
means of the marshalling line 19 to the exit position 15
as illustrated at the right-hand side of Fig. 6, when the
boarding end of the slide 25 is drawn to the side of the
ship and the liferaft and slide brough-t to a disposition
corresponding to that illustrated at the left-hand side
of Fig. 6.
The inflated liferaft and slide are attached to the side
of the ship in such a manner as to permit pivoting of
them into positions in which the slide, when viewed from
above, extends outwardly at an acute angle to the side of
the ship. ~o this end, the slide 25 shown in Fig. 6 is
provided with a pivotal head 34 hereinafter to be
described with reference to Figs. 7 to 9.
Referring now to Figs. 7 to 9, the liferaft 22 and slide
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25 are shown fully inflated with the boarding end of the
slide secured a-t the exit position 14 of the ship ll. As
illustrated, the slide 25, which may be of a length of 12
to 14 ft. (3.65 to 4.26 m) comprises two inflatable
5 support tubes 26 and 27 held in spaced parallel
relationship by inflatable struts (not shown) and a slide
sheet 28 secured along its longitudinal edges to the
upper sides of the tubes 26 and 27 in such a manner as to
form a slide path down which evacuees may slide under
some side restraint from the tubes 26 and 27. The lower
end of the slide 25 terminates at the entrance 24 to the
liferaft 22 and is releasably secured to the liferaft at
that position by Dutch lacing. Guide tubes 29 and 30
extend from the upper end of the slide 25 and provide
hand support rails for evacuees when taking up a sitting
position at the upper end of the slide. A slide path
extension is provided in the liferaft by a stressed sheet
31~ which extends between an upper peripheral buoyancy
tube 32 and a floor 33 of the liferaft.
The upper end of the slide 25 is provided with a pivotal
head 34 by means of which it is secured to the side of
the ship 11 at the exit opening 14. The head 34
comprises an inflatable cushion 35 which is releasably
attached to the vessel by hooks 36 which engage over a
horizontal support bar 37 and the arrangment is such that
the inflated cushion 35 hangs from the hooks 36 and bears
against the side 38 of the ship ll. The cushion 35 is of
elongate form and folded back upon itself to form upper
and lower limbs 39 and 40 which are held together by a
tie sheet 41. The upper limb 39 is attached at its end
to the ship by the hooks 36 while the lower limb 40 takes
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up a position in which its end bears against the side 38
of the ship 11. The cushion 35 supports a horizontally
disposed platform 42 to which is connected the upper end
of the support tubes 26 and 27 of the slide 25 and is
arranged for pivoting on the cushion 35 about a vertical
axis.
As best seen in Figs. 7 and 9, the platform 42 comprises
a D-shaped inflatable annular tube 44, the straight
portion of which has connected to it the upper ends of
the support tubes 26 and 27 by flexible web 45. The
D-shaped tube 44 is provided with a stressed top sheet 46
which serves as a floor of the platform for use by
evacuees when gaining access -to the slideway. The
D-shaped tube 44, which may have a diameter of the order
of 10 in (25.4 cm) rests on the upper surface of ~he
upper limb 39 of the cushion 35 and is held at that
position for pivoting movement about a vertical axis
through the cushion by a universal coupling tie cord 47
secured by a patch 48 to the underside of an intermediate
stressed sheet 49 and at the other end by a patch 50 to
the uppermost point on the cushion surface.
Referring in particular to Fig. 8, a compressed air
cylinder pack 51 which is housed in the container (17,18)
housing the packed liferaft 22 and slide 25 is utilised
for inflation of the liferaft 22 when the container
enters the water, and a further compressed air cylinder
52 is utilised for inflating the slide 25 in response to
a hard pull on the marshalling line 19 or a supplementary
line employed specifically for this purpose.
The pivotal head 34 of the slide 25, which inflates with
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the slide and forms part of it, provides for pivoting
movement of the slide 25 and liferaft 22 relatively to
the side of the ship through an angle approaching 180
degrees so that the liferaft 22 and slide 25 can take up
the most favourable disposition in adverse conditions
without buckling or distortion of the components forming
the slide 25 when it is subjected to strong water
currents and winds. In addition, the connecting web 45
between the upper end of the tubes 26 and 27 and the tube
44 of the platform 42 is such that the liferaft 22 can
rise and fall relatively to the exit opening 14 without
buckling of the slide components.
In operation, when the pivotal head 34 of the inflated
slide 25 is secured at the exit opening 14 by the hooks
36, evacuees, in turn, walk on to the platform 42, take
up a seated position on the upper end of the slide sheet
23 using the guide tubes 29 and 30 for support, slide
down the slide sheet 28 and descend direct into the
liferaft through the opening 24 where they are guided by
extension 31. When the liferaft 22 is full, an occupant
frees it from the slide 25 by actuating a release handle
(not shown) operable from within the liferaft and
effecting release of the Dutch lacing securing the lower
end of the slide 25 to the liferaft 22.
The pivotal head 34 of the slide 25 of the marine escape
unit described with reference to Figs. 7 to 9 of the
drawings may if desired be replaced by pivotal heads of
other forms. An alternative form of pivotal head is
illustrated in Fig. 10 of the accompanying drawings and
comprises an inflatable spherical ball 53 which is
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releasably attached to the ship 11 by an apron 54 in such
a manner that the inflated ball 53 hangs from the apron
54 and bears against the side 38 of the ship. The ball
53 supports a horizontally disposed platform 55 to which
is connected the upper end of the slide support tubes 26
and 27 by web 45 and is arranged for pivoting on the ball
53 about a vertical axis through the centre of the ball.
The platform 55 takes the same form as that of the
platform 42 of the head illustrated in Figs. 7 to 9 and
is connected to the ball 53 in the same manner as the
platform 42 by a universal coupling tie cord 47 extending
between an intermediate sheet 48 and the upper surface of
the ball 53.
It will be appreciated that by providing an inflatable
marine escape unit as hereinbefore described with
reference to the drawings, normal embarkation and
disembarkation positions on the ship may be utilised as
exit posi-tions without the need for stowing the escape
units in these regions. Clearly, the containers 17,18
housing the inflatable liferaft and slide assemblies may
be stowed at stowage positions remote from locations used
for normal embarkation and disembarkation of passengers.
It will, furthermore, be appreciated that the inflated
liferaft and slide may be pulled by the marshalling line
19 along the side of the ship to any other position from
which evacuees may leave the ship and indeed the pivotal
head 31 at the boarding end of the slide may simply be
attached to deck rails where no other exit position is
available or when all normal disembarkation positions are
already being used for evacuation into liferafts.
The slide forming part of the marine escape unit
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according to the first aspect of the invention is adapted
for use in a disposition in which it provides a descent
path sufficiently inclined for evacuees to be able to
slide down it under their own weight. It may
nevertheless be used in circumstances where evacuees may
run or walk down it, depending upon the agility of the
evacuee and the angle of the slide.
