GB2131369A

GB2131369A - Marine escape system

Info

Publication number: GB2131369A
Application number: GB08332419A
Authority: GB
Inventors: David Vernon Edwards
Original assignee: RFD Ltd
Current assignee: RFD Ltd
Priority date: 1982-12-06
Filing date: 1983-12-05
Publication date: 1984-06-20
Also published as: GB2131369B; GB8332419D0

Abstract

A marine escape system for use by evacuees disembarking from a vessel comprises an inflatable liferaft (15) and an inflatable slide (14) arranged for deployment with the inflated liferaft floating on the water and the inflated slide connected at a boarding end thereof to an exit position (13) on the vessel and at the other end to the liferaft. The slide (4) comprises a slideway portion (10) and a pivotal head (27) located at the boarding end of the slide. The head (27) includes an inflatable lower head portion (28) attached to the vessel and an inflatable upper head portion (30) integral with or attached to the slideway portion (10) and mounted on the lower head portion (28) for pivotal movement about a vertical pivotal axis. Two rigid support arms (38) are secured at their upper ends by flexible couplings to the vessel and at their lower ends to the upper head portion (30) at spaced positions thereon remote from the vessel to hold the upper head portion (30) against vertical displacement relative to the vessel, whilst permitting turning movement thereof about the pivotal axis. <IMAGE>

Description

SPECIFICATION Marine escape system The present invention relates to marine escape systems for use in the evacuation of passengers and crew from a marine vessel in an emergency.

In our copending Patent Application No.

8214124 an inflatable marine escape system has been proposed for use in an emergency by evacuees disembarking from a vessel of moderate freeboard, that is to say, having a freeboard of say between 3 to 6 m. The system comprises an inflatable liferaft and an inflatable slide which 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 connected at one end thereto and extending therefrom. The slide includes an inflatable slideway portion and a pivotal head located at the boarding end of the slide remote from the liferaft.The pivotal head includes a lower inflatable element for attachment to the vessel and an upper inflatable element attached to the slideway portion of the slide and arranged for pivotal movement relative to the lower inflatable element about a vertical or generally vertical pivotal axis, whereby the liferaft and the slideway portion of the slide can turn about the pivotal axis and take any one of a plurality of floating dispositions relative to the vessel.

The system described and claimed in our copending application has the advantage that it is compact when stowed, takes up little space at an exit position and yet provides for rapid disembarkation of evacuees direct into a liferaft.

The inflatable elements of the pivotal head of the slide furthermore provide for pivoting of the slide and liferaft under adverse weather conditions.

While the marine escape system described and claimed in our copending patent application is particularly suitable for use on vessels of moderate freeboard, it has been found that the inflatable elements forming the pivotal head of the slide can ride up at the exit position on the vessel in conditions when the slide is in a vertical plane perpendicular to the side of the vessel and the liferaft and slide are being forced by wind or currents in a direction toward the vessel.

It is an object of the present invention to provide in a marine escape system as described and claimed in our copending patent application means whereby riding up of the inflatable elements of the pivotal head of the slide can be avoided.

A marine escape slide system has also been proposed for use on large vessels in place of or in addition to davit launched lifeboats. The system comprises an inflatable slide and platform assembly which is stowed uninflated at a stowage position on the deck of the vessel 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 vessel. Uninflated liferafts housed in containers are discharged from the deck of the vessel into the water and members of the 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.

It has been found that, in the marine escape slide system proposed for large vessels, buckling or twisting of the slide can occur when the floating platform is subjected to adverse strong currents or winds. The use of restraining 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 vessel in such a manner as to permit pivoting of the floating platform and inflated slide so that they can take up a position in which the slide extends outwardly and downwardly in a vertical plane inclined at an acute angle to the side of the vessel. Mechanism hitherto proposed for achieving pivoting of the slide and platform in such escape systems encumber the deck at the escape position and are of generally complex and heavy construction.For example, a pivotal steel floor has been provided which can pivot from a retracted position on the deck of the vessel to a cantilevered position outstanding from the side of the vessel. In another arrangement a pivotal gantry has been proposed which can be pivoted to a cantilevered disposition for use by evacuees gaining access to the slide.

The mechanism hitherto proposed for pivoting the slide and platform in the escape systems hereinbefore referred to have been found suitable for use on large vessels since the weight of the system is no serious penalty and the vessels usually have adequate deck space. It may, however, be considered desirable in some circumstances to replace the mechanisms by a pivotal head as proposed in copending Patent Application No. 8214124. Such an arrangement would however be subject to the disadvantage that the inflatable elements of the pivotal head of the slide tend to ride up in adverse circumstances.

It is a further object of the present invention to provide a marine escape system as proposed in copending Patent Application No. 8214124 which can also be used on large vessels and which utilises an inflatable slide and an inflatable platform assembly.

It is yet a further object of the present invention to provide a marine escape system as proposed in our copending Application No. 8214124 which is more stable in use and offers to evacuees a greater sense of security.

According to the present invention, there is provided a marine escape system for use by evacuees disembarking from a vessel wherein an infalatable liferaft or platform and an inflatable slide are arranged to be discharged together in collapsed conditions from an exit position on the vessel for deployment on the water with the inflated liferaft or platform floating on the water and the inflated slide connected at a boarding end thereof to the exit position and at the other end to the liferaft or platform, wherein the slide comprises a slideway portion and a pivotal head located at the boarding end of the slide, wherein the pivotal head includes an inflatable lower head portion attached to the vessel at the exit position and an inflatable upper head portion integral with or attached to the slideway portion of the slide and mounted on the lower head portion for pivotal movement relative thereto about a vertical or generally vertical pivotal axis, whereby the liferaft or platform, the upper head portion and the slideway portion of the slide can turn about the pivotal axis between an undeflected deployed disposition of the slide in which the slideway portion extends outwardly and downwardly from the vessel with the longitudinally extending medial plane of the slideway portion vertical and perpendicular to the side of the vessel and any one of a plurality of deflected deployed dispositions in each of which the slideway portion extends downwardly and outwardly along a line lying in a vertical plane inclined to the side of the vessel and wherein rigid support means is secured at an upper end thereof by flexible coupling means to the vessel and at a lower end thereof to the upper head portion at a first position thereon remote from the vessel and on one side of the vertical medial plane of the slideway portion in the undeflected deployed disposition of the slide and at a second position thereon remote from the vessel, spaced from the first position and on the other side of the vertical medial plane of the slideway portion in the undeflected deployed disposition of the slide, whereby the support means holds the upper head portion in the regions of the first and second positions against vertical displacement relative to the vessel.

Preferably the rigid support means comprises first and second rigid arms, the first of which is connected at its lower end to the upper head portion of the slide at the first position thereon and the second of which is connected at its lower end to the upper head portion at the second position thereon. The flexible coupling means preferably takes the form of a first flexible coupling for securing the upper end of the first arm to the vessel at a first position on one side of the vertical medial plane of the slideway portion in the undeflected deployed disposition of the slide and a second flexible coupling securing the upper end of the second arm to the vessel at a second position on the other side of the vertical medial plane of the slideway portion in the undeflected deployed disposition of the slide.

Preferably, the arms are arranged to be of constant equal length in use and are symmetrically arranged with respect to the medial plane of the slideway portion in the undeflected deployed disposition of the slide, whereby when the slide turns from the undeflected deployed disposition to one of the deflected deployed dispositions the arms cause a lowering of the upper head portion in a region thereof adjacent the vessel and a raising of the upper head portion in a region thereof remote from the vessel.

In a preferred embodiment of the invention the lower head portion is provided with attachment means for attaching it to the vessel at the exit position for deployment to an operative position in which it projects from the side of the vessel and the upper head portion supports the lower head portion in its operative position. The lower head portion preferably serves in its operative position to hold the upper head portion away from the side of the vessel.

Preferably, the lower head portion holds the upper head portion away from the side of the vessel by means of a pivotal connection which holds the two head portions together while allowing relative pivotal movement of them about the pivotal axis. In the preferred embodiment of the invention the pivotal connection comprises a flexible tie which is connected at one end to the upper head portion, extends along the pivotal axis of the upper head portion and is connected at its other end to the lower head portion, whereby pivotal movement of the upper head portion about the pivotal axis is achieved with twisting of the tie.

The inflatable upper head portion of the slide is preferably made from a flexible fabric and the lower ends of the two arms are secured to the fabric in a manner which permits movement of the upper head portion relative to the lower ends of the arms by flexing of the fabric in the regions of the lower ends of the arms. The flexing of the fabric is preferably made such as to reduce the lowering of the region of the upper head portion adjacent the vessel.

The embodiments of the invention will now be described by way of example with reference to the accompanying drawings in which: Fig. 1 is a schematic side elevation of part of a marine vessel of moderate freeboard fitted with a marine escape system according to a first embodiment of the invention; Fig. 2 is a schematic plan view of the vessel and marine escape system shown in Fig. 1; Fig. 3 is a schematic sectional end view of part of the vessel and marine escape system illustrated in Figs. 1 and 2; Fig. 4 is an enlarged perspective view of the vessel and marine escape system illustrated in Figs. 1 and 2, showing the slide and liferaft in an undeflected deployed disposition; Fig. 5 is a schematic perspective view corresponding to that shown in Fig. 4 and showing the slide and liferaft in a deflected deployed disposition; and Fig. 6 is a schematic sectional end view corresponding to that shown in Fig. 3 and illustrating a marine escape system according to a second embodiment of the invention.

Referring first to Figs. 1 and 2, a marine vessel 11 operating as a passenger and vehicle ferry and having a freeboard of the order of 3 m is provided with exit doors 1 2 normally used for the embarkation and disembarkation of passengers.

One of the doors 1 2 has been removed to present a door frame 1 3 for housing a marine escape system shown deployed in Figs. 1 and 2 and which comprises a slide 14 and two 42-person liferafts 1 5 and 16 which as shown in Fig. 2 are releasably secured together at their peripheries to form an 84-person survival unit.

Each of the liferafts 1 5 and 16 is of circular planform and is provided with a canopy 1 8 having four openings 1 9 for use by survivors in gaining access to or exit from the liferaft. Each of the liferafts 1 5 and 1 6 has a capacity to take up to a maximum of 42 persons, has a diameter of the order of 18 feet (5.48 m), has a height of the order of 6 feet (1.82 M) and is constructed from two superposed peripheral buoyancy tubes 20 and 21, each having a diameter of the order of 1 6 inches (40.6 cm).The slide 14 which may be of a length of 12 to 14 feet (3.65 to 4.26 m) comprises a slideway portion 10 formed by two inflatable support tubes 22 and 23 held in spaced parallel relationship by inflatable struts (not shown) and a slide sheet 24 secured along its longitudinal edges to the sides of the tubes 22 and 23 in such a manner as to form a slideway down which evacuees may slide under side restraint from the tubes 22 and 23. The lower end of the slide 14 termines in one of the entrances 1 9 of the liferaft 1 5 and is releasably secured to the liferaft 1 5 at that position by rope loops (not shown). Guide tubes 25 and 26 extend from the upper end of the slide 1 4 and provide hand support rails for evacuees when taking up a sitting position at the upper end of the slide.

Referring now to Fig. 3, the upper end of the slide 14 is provided with a pivotal head 27 by means of which it is secured to the door frame 1 3.

The head 27 comprises an inflatable lower head portion in the form of an inflatable cushion 28 which is attached to the base of the door frame 1 3 by straps 29. The cushion 28 is, as shown in Fig.

3, of elliptical cross-section and is of circular planform. The pivotal head 27 furthermore includes an inflatable upper head portion 30 formed by the upper ends of the support tubes 22 and 23 joined together by a bridging tube section 31. The slide sheet 24 is extended so as to serve as a floor for use by evacuees when gaining access to the slide 14. The upper head portion 30 of the slide 1 4 is connected to the cushion 28 by a pivotal coupling in the form of a tie cord 33 secured by a patch 34 to the underside of slideway sheet 24 and at the other end by a patch 36 to the uppermost point on the surface of the cushion 28.

A pivotal arm 28 is connected at its lower end by a rope loop and pin (not shown) to a reinforcing patch on the upper surface of the tube 23, extends upwardly and inwardly toward the vessel 11 and is secured at its upper end to the door frame 1 3 by a universal coupling 39. A further pivotal arm 37 which is not shown in Fig. 3 but which can be seen in the other figures is likewise connected at its lower end to the tube 22 and at its upper end to the door frame 1 3. The arms 37 and 38 are rigid inextensible arms and are during deployment of the slide 14 and the liferafts 15 and 16 pivotable from the position shown in broken line in Fig. 3 to the position shown in full line in Fig. 3. As best seen in Fig. 4, the arms 37 and 38 are secured at their upper ends to opposite sides of the door frame 13 and are symmetrically arranged with respect to the slide 14.The slide 14 is shown in Fig. 4 in its undeflected deployed disposition in which the slideway portion 10 extends outwardly and downwardly from the vessel with its longitudinally extended medial plane vertical and perpendicular to the side of the vessel 11. As can be seen from Fig. 4, the arm 37 is secured to points on the tube 22 and the door frame 13 on one side of the vertical medial plane of the slide while the arm 38 is secured to points on the tube 23 and the door frame 1 3 on the other side of the vertical medial plane of the slide.

Referring again to Fig. 3, the door frame 13 has fitted within it a stowage cover 41 which is held in place by a lockable pivotal arm 42. The door frame 1 3 is furthermore fitted with a lockable removable door 43 which serves to close the door frame opening and the open outermost end of the stowage cover 41. The slide 14 and the liferafts 15 and 16 are housed in the cover 41 in a collapsed and folded condition as shown in broken line, with the collapsed slide 14 rolled round the collapsed liferafts 1 5 and 16, and are arranged to be inflated out of the cover 41 by air or gas under pressure delivered to the slide 14 from inflation cylinders 44 and 45 also housed within the cover 41.

In an emergency, the door 43 is unlocked and the inflation cylinders 44 and 45 activated to commence inflation of the slide 14 within the cover 41. Inflation of the slide produces an outward thrust on the removable door 43 which is pushed clear of the door frame 13 and discharged into the water. The slide 14 continues to inflate pushing out the packed and folded liferafts 1 5 and 1 6 which then commence to inflate upon discharge into the water, the weight of the slide 14 and the liferafts 1 5 and 1 6 being sufficient to pull the whole of the slide 14 including the pivotal head 27 clear of the door frame 13 and into the position shown in in full line Fig. 3 where the inflatable cushion 28 is held by straps 29 and the upper head portion 30 of the slide 1 4 by the arms 37 and 38 which during deployment of the slide 14 and Iiferafts 1 5 and 1 6 have pivoted from the position shown in broken line in Fig. 3 to the position shown in full line.

Following deployment of the slide 1 4 and the liferafts 1 5 and 16, the locking arms 42 is raised as shown in outline and the cover 41 detached and withdrawn inwardly from the door frame 13 to provide access to the slide 14 by evacuees.

In good weather conditions when the slide 1 4 and the liferafts 1 5 and 1 6 are not subjected to side loads from high winds or from water currents, the slide takes up the disposition shown in Fig. 4 in which its longitudinal medial plane is vertical and perpendicular to the side of the vessel 11 The two arms 37 and 38 serve to support the pivotal head 27 of the slide 14 in a disposition outstanding from the side of the vessel, while the cushion 28 serves to hold the upper head portion 30 of the pivotal head away from the side of the vessel 11.In this disposition, if an adverse wind or water current develops which imposes an end load on the slide directed to the vessel the upper head portion 30 and the cushion 28 forming the pivotal head 27 are held in the position shown by the pivotal arms 37 and 38 which resist both compressive and tensile loads imposed upon them. In this way, riding up of the upper head portion 30 and the cushion 28 in such adverse conditions is prevented.

It is however more usual to experience conditions in which the slide 14 and the Iiferafts 1 5 and 1 6 are subjected to side loads from wind or currents, which would in the absence of the pivotal head 27 of the slide 14 give rise to buckling of the slide 14. By so arranging for the upper head portion 30 of the slide 14 to be pivotal about a vertical axis on the cushion 28, the slide 14 and the liferafts 1 5 and 16 can under such adverse side loads slew to the side of the vessel and take up a disposition for example as illustrated in Fig. 5 in which the slideway portion 10 extends downwardly and outwardly from the door frame 13 along a line lying in a vertical plane inclined to the side of the vessel 11.It will however be seen that in addition to slewing of the slide 14 in this way the slide 14 becomes tilted under the action of the inextensible pivotal arms 37 and 38, the former of which causes a lowering of the upper head portion 30 in the region thereof adjacent the side of the vessel 11 while the latter causes a raising of the upper head portion 30 in a region thereof remote from the vessel 11.

While tilting of the upper head portion 30 and the slideway portion 10 of the slide 14 as shown in Fig. 5 might at first be thought to be a disadvantage, experience has shown that the disposition of the arms 37 and 38 as well as the disposition of the upper head portion 30 and the slideway portion 10 of the slide give an added sense of security to evacuees leaving the vessel by means of the slide. Firstly, the slight tilting of the upper head portion 30 alone has been found to provide evacuees with a sense of security which is greater than that if the upper head portion 30 were maintained in a horizontal disposition.

Secondly the arms 37 and 38 take up a skew disposition as shown in Fig. 5 with the arm 38 offering a hand support which is advantageously raised on the outboard side of the slide 14. Thirdly, the slight tilting of the slideway portion 10 offers a measure of protection to evacuees against strong winds which would give rise to the slewing of the slide toward the side of the vessel 11.

The degree to which the upper head portion 30 of the pivotal head 27 becomes tilted as shown in Fig. 5 is of course determined by the length and dispositions of the arms 37 and 38 and the dimensions of the upper head portion 30. A reduction in the degree of tilting of the upper head portion 30 can however be achieved by taking advantage of the fact that the arms 37 and 38 are connected at their lower ends to the flexible fabric of the tubes 22 and 23 forming the upper head portion 30, which for example would in the disposition of the slide shown in Fig. 5 become locally depressed at the lower end of the arm 37 and locally raised at the lower end of the arm 38.

In an alternative embodiment of the invention illustrated in Fig. 6, the pivotal head 27 comprises the inflatable cushion 28 and an upper head portion 30' formed by an annular tube 31' of D-shaped configuration, the straight portion of which has connected to it a bridging portion 23' joining the upper ends of the support tubes 22 and 23.

The D-shaped tube 31' is provided with a stressed top sheet 32 which serves as a floor for use by evacuees when gaining access to the slide 14. The D-shaped tube 31' is connected to the cushion 28 by a pivotal coupling in the form of a tie cord 33' secured by a patch 34' to the underside of an intermediate stress sheet 35 and at the other end by a patch 36' to the uppermost point on the surface of the cushion 28.

The upper head portion 30' in the embodiment of the invention illustrated in Fig. 6 is constrained in the same manner as the upper head portion 30 of the embodiment of the invention described with reference to Figs. 1 to 5 and is pivotal on the cushion 28 also in the same manner. The connection between D-shaped tube 31' of the upper head portion 30 and the bridging portion 23' of the support tubes 22 and 23 in the embodiment described with reference to Fig. 6 is however such as to allow the slideway portion 10 of the slide 14 to pivot about the connection in response to variations in the height of the deployed liferafts 15 and 1 6 relative to the head portion 30 caused for example by swell or the angular disposition of the vessel 11 in the water.

In the embodiment of the invention illustrated in Fig. 6, the flexible storage cover 41 is replaced by a rigid stowage container 41' held in place by a lockable displaceable arm 42'. Following deployment of the slide 14 and the liferafts 1 5 and 16, the locking arm 42' is first extended as shown in outline and then lowered to the further position shown in outline, whereupon the container 41' is withdrawn inwardly from the door frame 13 to provide access to the slide 14 by evacuees.

Although in the embodiments of the invention hereinbefore described with reference to the drawings the pivotal arms 37 and 38 are made inextensible, it may be found that for some purposes arms of adjustable length could with advantage be provided.

Claims

1. A marine escape system for use by evacuees disembarking from a vessel wherein in inflatable liferaft or platform and an inflatable slide are arranged to be discharged together in collapsed conditions from an exit position on the vessel for deployment on the water with the inflated liferaft or platform floating on the water and the inflated slide connected at a boarding end thereof to the exit position and at the other end to the liferaft or platform, wherein the slide comprises a slideway portion and a pivotal head located at the boarding end of the slide, wherein the pivotal head includes an inflatable lower head portion attached to the vessel at the exit position and an inflatable upper head portion integral with or attached to the slideway portion of the slide and mounted on the lower head portion for pivotal movement relative thereto about a vertical or generally vertical pivotal axis, whereby the liferaft or platform, the upper head portion of the slide and the slideway portion of the slide can turn about the pivotal axis between an undeflected deployed disposition of the slide in which the slideway portion extends outwardly and downwardly from the vessel with the longitudinally extending medial plane of the slideway portion vertical and perpendicular to the side of the vessel and any one of a plurality of deflected deployed dispositions in each of which the slideway portion extends downwardly and outwardly along a line lying in a vertical plane inclined to the side of the vessel and wherein rigid support means is secured at an upper end thereof by flexible coupling means to the vessel and at a lower end thereof to the upper head portion at a first position thereon remote from the vessel and on one side of the vertical medial plane of the slideway portion in the undeflected deployed disposition of the slide and at a second position thereon remote from the vessel, spaced from the first position and on the other side of the vertical medial plane of the slide in the undeflected deployed disposition of the slide, whereby the support means holds the upper head portion in the regions of the first and second positions against vertical displacement relative to the vessel.

2. A system according to claim 1, wherein the rigid support means comprises first and second rigid arms, the first of which is connected at its lower end to the upper head portion of the slide at the first position thereon and the second of which is connected at its lower end to the upper head portion at the second position thereon.

3. A system according to claim 2, wherein the flexible coupling means takes the form of a first flexible coupling for securing the upper end of the first arm to the vessel at a first position on one side of the vertical medial plane of the slideway portion in the undeflected deployed disposition of the slide and a second flexible coupling securing the upper end of the second arm to the vessel at a second position on the other side of the vertical medial plane of the slideway portion in the undeflected deployed disposition of the slide.

4. A system according to claim 3, wherein the arms are arranged to be of constant equal length in use and are symmetrically arranged with respect to the medial plane of the slideway portion in the undeflected deployed disposition of the slide, whereby when the slide turns from the undeflected deployed disposition to one of the deflected deployed dispositions the arms cause a lowering of the upper head portion in a region thereof adjacent the vessel and a raising of the upper head portion in a region thereof remote from the vessel.

5. A system according to claim 4, wherein the lower head portion is provided with attachment means for attaching it to the vessel at the exit position for deployment to an operative position in which it projects from the side of the vessel and the upper head portion supports the lower head portion in its operative position.

6. A system according to claim 5, wherein the lower head portion serves in its operative position to hold the upper head portion away from the side of the vessel.

7. A system according to claim 6, wherein the lower head portion holds the upper head portion away from the side of the vessel by means of a pivotal connection which holds the two head portions together while allowing relative pivotal movement of them about the pivotal axis.

8. A system according to claim 7, wherein the pivotal connection comprises a flexible tie which is connected at one end to the upper head portion, extends along the pivotal axis of the upper head portion and is connected at its other end to the lower head portion, whereby pivotal movement of the upper head portion about the pivotal axis is achieved with twisting of the tie.

9. A system according to any of claims 2 to 8, wherein the inflatable upper head portion of the slide is made from a flexible fabric and the lower ends of the two arms are secured to the fabric in a manner which permits movement of the upper head portion relative to the lower ends of the arms by flexing of the fabric in the regions of the lower ends of the arms.

10. A system according to claim 9, wherein the flexing of the fabric is made such as to reduce the lowering of the region of the head portion adjacent the vessel.

11. A marine escape system substantially as hereinbefore described with reference to Figs. 1 to 5 or Fig. 6 of the accompanying drawings.