GB2279045A - Method and apparatus for recovery of survivors off-shore from ships lifeboats and the like - Google Patents

Abstract

A method of rescuing survivors off-shore in a ships lifeboat 2 utilises a rescue craft 1 of the oil rig suppply type i.e. having a stem of low height to constitute a take-on entry. The method comprises connecting a tow-line 8 from the rescue craft 1 to the lifeboat 2, extending a mat 4 astern from the take-on entry and placing a floating docking device 13 astern of the mat 4. The rescue craft 1 is manoeuvred so that the lifeboat 2 is aligned with the docking device 13 and the mat 4; then the lifeboat 2 is pulled onto the docking device 13 which in turn is pulled over the mat 4 and onto the craft via the take-on entry 5 to enable survivors to be removed directly from the lifeboat 2 onto the deck of the rescue craft 1. The docking device 13 is preferably of tubular open-work frame form (see Fig 8) with guide means (8) for the lifeboat tow line 8. <IMAGE>

Description

Method and Apparatus for Recovery of Survivors Off-Shore from Ships Lifeboats and the Like The present invention relates to a method and apparatus for recovery of survivors off-shore, in particular survivors aboard ships' lifeboats i.e. lifeboats which are carried on ships and other vessels and on oil/gas rigs and which are launched in an emergency, and especially lifeboats of the totally enclosed type, usually known as totally enclosed survival craft (TESC).

Totally enclosed survival craft (TESC) are now the prevalent form of lifeboat used off-shore on oil/gas platforms. In an emergency, survivors occupy the TESC which is launched onto the sea from the platform. Up-until-now the standard procedure for recovery of survivors from the TESC has been by means of a rescue craft which brings the TESC alongside to enable a rope ladder or the like to be dropped to the TESC from the deck of the rescue craft, and survivors can then emerge from the TESC via an open hatch thereof and move up the ladder to the deck of the rescue craft. There are two problems with this procedure.

Firstly, even in a moderate sea it can be difficult for the heavier rescue craft to come alongside the TESC without seriously damaging the relatively fragile survival craft and injuring the survivors therein.

Secondly, it is very possible that some of the survivors will have been injured during the emergency and there will be considerable difficulty in transferring these survivors to the rescue craft via the rope ladder, and further many of the non-injured survivors may be in a poor physical condition due to the trauma of the emergency, survival craft motion, confinement and sea-sickness so even these survivors may have difficulty in climbing the ladder onto to rescue craft.

It is the principal object of the present invention to overcome these problems.

Therefore, according to a first aspect of the present invention a method of recovering survivors off-shore from a ship's lifeboat or the like comprises placing a tow-line between the lifeboat and a rescue craft, relatively positioning the lifeboat and the rescue craft so that the lifeboat is aligned with a take-on entry of the rescue craft, extending a mat device away from said entry towards the lifeboat moving said lifeboat by means of the tow-line towards the entry so as to be received by a docking or cradle device, and pulling the docking or cradle device with the lifeboat thereon over said mat device and onto the rescue craft via said take-on entry.

Preferably said take-on entry is located at the stern of the rescue craft, while conveniently the rescue craft can comprise an off-shore supply type vessel or the like.

The tow-line can be connected between the rescue craft and the lifeboat by having the lifeboat put out a sea anchor on an anchor line and by having the rescue craft retrieve said anchor line by a grappling procedure. The step of pulling the docking device onto the rescue craft can be achieved by a line of stronger and heavier construction than the tow-line between the lifeboat and the rescue craft. In the method, the rescue craft may move forwardly to ensure that the lifeboat, and docking device are aligned with the craft but the forward speed, which can be slow, will be dependent on the sea.

The mat device will have a sea moderating effect when placed in use, and preferably has substantial neutral buoyancy. The mat device is preferably of rubber (natural or neoprene) or other plastics material, can be apertured to dampen wave action, and preferably is foldable into a reasonably compact storage condition.

Preferably, guide means are present in the docking device for the tow-line thereby encouraging the lifeboat to take up an aligned position, for example line astern, with the docking device and the rescue craft. The docking device will be provided with suitable buoyancy to facilitate reception of the lifeboat.

It is envisaged that certain of the steps of the method will be effected by remote control, e.g by a radio link, for example the release of the sea anchor from the lifeboat.

According to a further aspect of the present invention a docking device for use in the above inventive method comprises a lifeboat support structure including a base and side members joined to the base to locate a lifeboat on the docking device, the support structure including an open end for reception of the lifeboat, buoyancy means, and adjustable means for holding the lifeboat on the support structure.

In a preferred embodiment, the support structure is of open-work frame form and can be foldable or dismantlable to facilitate storage. The support structure can include tubular members providing said buoyancy means, while the adjustable means preferably comprises an inflatable device which is preferably remotely operable.

The support structure is preferably fitted with guide means for the tow-line to the lifeboat, preferably the support structure is in the form of a sled with the base adapted for lower friction sliding movement on the deck of the rescue craft.

The present invention is also a recovery sled comprising a buoyant structure in the form of an open framework, adapted to slide off and on the deck of a suitably adapted ship over a sea moderating mat and to hold a lifeboat or similar survival craft within.

Therefore, the present invention provides an effective means for rescuing survivors off-shore from lifeboats and the like, without the need for bulky and substantial additions to the delegated rescue craft, especially as the mat and docking devices can be of a foldable or dismantlable form.

An embodiment of the present invention will now be described by way of example with reference to the accompanying drawings wherein: Figs 1 to 6 show the sequence of steps for recovering TESC form lifeboat off-shore in accordance with the present invention; Fig 7 shows a pictorial view of an off-shore supply boat (OSB), equipped to carry out the inventive recovery method; and Fig 8 shows a pictorial view of a docking device in accordance with the present invention for use in the recovery method.

A method of recovering a lifeboat 2 off-shore, especially a lifeboat in the form of a totally enclosed survival craft (TESC) is shown schematically in Fig 1 to 6.

For this method a delegated recovery or rescue craft or boat 1 is especially equipped for the operation. Conveniently, the recovery craft 1 comprises an off-shore supply boat (OSB- Fig 7) as the low cargo deck 1A and take-on entry 1B at the stern of the OSB greatly facilitate the recovery operation. The presence of the stern roller 5 is also beneficial.

The major equipment required is: (i) a docking or. recovery device 13 for the lifeboat 2 and (ii) a sea moderating mat 4 which can be located to extend from the stern of the boat 1.

For the out of use condition the docking device 13 can be foldable or dismantlable, while the mat 4 can be rolled to a relatively compact size whereby both can be stowed in a compact condition with the result that the storage space needed for these items can be small. Other additional requirements are the installation of remote control means, for example, a radio controlled transceiver, especially for actuation of a sea anchor on the lifeboat 2, the lifeboat being suitably equipped to respond to the radio signal, and line throwing equipment to grapple the sea anchor line 3 of the lifeboat 2. If necessary additional bollards can be fitted to the boat 1 for handling of the docking device 13 and the mat 4.

Lifeboats (or TESC'S) with which the present invention is particularly concerned typically have a capacity of about 60 people. There are several makes on the market, and for the deployment with the present recovery method, the TESC need be modified only by the addition of the sea anchor.

This can be a "bolt on" canister, with the line fastened to the bow towing bracket. Also these craft are very often specified for use on sea going ships, although the regulations still allow for the use of open lifeboats on ships. The sea anchor system would be activated by radio control from the recovery boat 1. Each off-shore installation would have a range of frequencies, known to the recovery boat or boats for that field. Alternatively, the sea anchor could also be activated manually from within the TESC.

The docking device comprises a sled 13 of open-work tubular form (see Fig 8) so as to constitute a cradle for the lifeboat 1 to be recovered. The sled 13 comprises a base or bottom 18 and side portions 20A/B joined to the bottom 18 by lateral tubes 21, the side portions 20A/B converging forwardly to be joined to a front plate 22 including a guide hole 9 for a towline between the lifeboat 2 and the recovery boat 1, said towline comprising the sea anchor line 3 and a line 8 extending from the boat 1. The guide hole 9 is sufficiently large to allow passage of the joint of the line 8 from a winch 10 on boat 1 and that from the sea anchor line 3.

The sled 13 is provided with satisfactory buoyancy and in particular the tubular members of the side portions 20A/B are buoyant to provide the sled 13 with the necessary stability when in the water. An inflatable pack 17 or elements is also provided; in Fig. 8 only one pack 17 is shown at the side 20B but desirably there will be a similar balancing pack at the side 20A, and indeed even further inflatable packs could be present. The packs 17 can be removed from the sled 13 in the out-of-use condition for protection. The pack 17 is inflated from a bottle pack (not shown) attached to the sled 13. When exhauted the bottle pack may be replaced with a fresh bottle pack or alternatively replenished from an air supply on the boat 1.

The bottom 18 preferably has a reduced friction characteristic for example by applying PTFE sheeting, to minimise friction between the sled and the deck 1A and the stern roller 5 during mpvement of the sled thereon.

Further, the sled 13 is preferably dismantlable, for example, by being capable of being split into two parts, or alternatively the sled may be foldable into a substantively flat condition or possibly sub-assembled from the bottom and the sides, and the front portion could fold or be assembled from parts. This should be acceptable as there will be an inevitable time lag (eg 1 hour) between the initial warning notice and arrival of the recovery boat 1 at the emergency scene, this period being sufficient to enable assembly of the sled 13 the front pointing of the sled includes attachments points 19 for a towing bridle 16 of the sled.

The sea moderating mat 4 can be deployed from an above deck stowed position, probably rolled around a tubular of fairly small diameter. The mat 4 will be laid flat on the after deck 1A and can be assisted over the stern roller 5 by drogues (not shown) at each aft corner of the mat 4. The mat 4 can have a pattern of large diameter holes (not shown) over its entire surface to avoid severe wave movement effects and suitably can over its entire surfaced be made of a rubber or neoprene material. The mat 4 serves to moderate the sea locally at the stern, and will have almost neutral buoyancy. After use, the mat can be retrieved onto the deck, or cut loose with small buoys attached, for recovery later.

The method of recovering a lifeboat (TESC) is as follows:- the recovery (rescue) boat 1 is positioned up weather (per wind W) of the lifeboat 2 (TESC) to be rescued and the boat 1 activates the remotely controlled sea anchor including line 3 attached to the bow of the lifeboat 2. The speed of the lifeboat 2 is reduced, allowing the lifeboat to stream behind its sea anchor.

The recovery boat 1 releases the sea moderating mat 4 over the stern roller 5 and secures the mat cables from bollards 15 in a position just astern of the transom. A grappling line 6 is fired from the recovery boat 1 using line throwing apparatus 7 to go over the sea anchor line 3 as shown in Fig 1. The sea anchor line 3 is then hauled on board the recovery boat and fastened to the end of the recovery line 8 which has been fed through the guide hole 9 in the recovery sled 13 and held on the boat 1 by the main winch 10.

The recovery boat 1 then steams up weather at a moderate ahead speed, to ensure that the lifeboat 1 follows astern as shown in Fig 2. The recovery sled 13 is then launched off the deck 1A of the boat 1, by means of wires 11 from the capstans 14 on each side of the aft weather deck.

The sled is secured by a line 12 payed out from the main winch 10 to a bridle 16, so that it also follows astern of the recovery boat 1. As the recovery line 8 is already fed through the sled 13, all three items, ie, recovery boat 1, recovery sled 13 and lifeboat 2 become a line astern" formation, and kept in this position due to the forward motion of the boat 1, all as shown in Fig 3.

Once in a stable line, the recovery line 8 is pulled in, drawing the lifeboat 2 into the sled 3 (Fig 4). When the lifeboat 2 is in place, the recovery boat 1 remotely activates the inflation elements 17 within the recovery sled 13. These hold the lifeboat 2 firmly in position, but without crushing, within the recovery sled.

The sled line 12 is then pulled in (Fig 5), bringing both the lifeboat 2 and the sled towards the recovery boat 1. The recovery line 8 is kept slack alongside the sled line 12 so that the load is taken on the sled line 12 only.

The sled 13 is then pulled across the sea moderating mat 4, over the stern roller 5 and onto the deck 1A. The sled 13 is secured on the deck 1A by wires from the capstans 14 (as shown in Fig 6), the hatches opened, and the survivors rescued from the lifeboat 2.

If there is a need to recover more lifeboats, the hatches of the lifeboat 2 in the sled 13 are battened down, and the sea anchor transferred to the stern of the lifeboat.

The sled is then relaunched over the stern whilst the boat 1 steams ahead up weather. Once the sled 13 is afloat, the boat 1 remotely activates the inflatable elements 17, this time to deflate , thus allowing the lifeboat 2 to drift astern out of the sled 13, aided by the sea anchor, for recovery later. The now empty recovery sled 13 is retrieved onto the deck lA, and a further lifeboat recovered as before. The above sequence may be repeated until all manned lifeboats have been recovered. When that is complete, the sea moderating mat 4 is recovered, or if the weather conditions do not allow this, it could be cut loose, with suitable buoys attached, for recovery later.

As the sled 13 and the lifeboat 2 come over the stern roller 5 during recovery, the sled and the lifeboat may be inclined quite sharply from the horizontal but this inclination change will only be of a very transient nature so should be acceptable. The mat 4 of the stern has - a subsidiary function of preventing the sled 13 (or ropes and the like) from moving under the stern of the boat 1.

It is a considerable advantage of the present recovery method, that recovery can be effected from the single boat 1 without having to launch or use a back-up craft - this is particularly beneficial in very severe weather conditions in which the present invention should be especially useful.

However, in calmer conditions a back-up craft, such as a rigid inflatable (RIB), may be usefully employed say to connect the towline 8 to the lifeboat 2, and this of course may be needed if it were not possible to release a sea anchor from the lifeboat.

Modifications are of course possible. For example, a different form of docking device (sled) could be used, and an economic form could be obtained by using a severed forward portion of a redundant vessel eg. fishing boat (complete say with whaleback) suitable modifications being made to the portion including the provision of appropriate buoyancy. This alternative docking device however, has the definite disadvantage of being bulky so requiring greater storage space.

The mat 4 could be modified and in particular may be rigidised by having inflatable tubular portions: this modification should assist the transfer of the sled 13 onto the boat deck 1A and may be especially useful for certain types of rescue craft - ie. other than OSB's.

The above method and apparatus of the present invention provides an effective method of recovery of survivors in a lifeboat, especially in severe conditions, and an especially beneficial feature is that no real permanent adaptation need be applied to a boat for it to serve as a rescue craft. The major items of the recovery apparatus can be transferred from boat to boat.

Claims (22)

1. A method of recovering survivors off-shore from a ship's lifeboat or the like comprising placing a tow-line between the lifeboat and a rescue craft, relatively positioning the lifeboat and the rescue craft so that the lifeboat is aligned with a take-on entry of the rescue craft, extending a mat device away from said entry towards the lifeboat, moving said lifeboat by means of the tow-line towards the entry so as to be received by a docking or cradle device, and pulling the docking or cradle device with the lifeboat thereon over said mat device and onto the rescue craft via said take-on entry.

2. A method as claimed in claim 1 or 2, wherein said takeon entry is located at the stern of the rescue craft.

3. A method as claimed in claim 1 or 2, wherein the rescue craft comprises an off-shore supply type vessel or the like.

4. A method as claimed in any one of the preceding claims, wherein the tow-line is connected between the rescue craft and the lifeboat by having the lifeboat put out a sea anchor on an anchor line and by having the rescue craft retrieve said anchor line by a grapplings procedure.

5. A method as claimed in any one of the preceding claims wherein the step of pulling the docking device onto the rescue craft is achieved by a line of stronger and heavier construction than the tow-line between the lifeboat and the rescue craft.

6. A method as claimed in any one of the preceding claims wherein when the tow line is connected between the rescue craft and the lifeboat the rescue craft moves forwardly to ensure that the lifeboat, and docking device are aligned with the rescue craft.

7. A method as claimed in any one of the preceding claims, wherein the lifeboat is pulled onto the docking device, and the docking device with the lifeboat therein is pulled onto the rescue craft by means of a winch on the rescue craft.

8. A method as claimed in any one of the preceding claims, wherein the mat device has a sea moderating effect when placed in use, and has substantial neutral buoyancy.

9. A method as claimed in claim 8, wherein the mat device is of rubber (natural or neopreme) or plastics material, and is foldable into a compact storage condition.

10. A method as claimed in claim 8 or 9, wherein the mat is apertured to facilitate damping of wave action.

11. A method as claimed in any one of the preceding claims, wherein guide means are present in the docking device for the tow-line to encourage the lifeboat to take up an aligned position, for example line astern, with the docking device and the rescue craft.

12. A method as claimed in any one of the preceding claims, wherein the docking device is provided with suitable buoyancy to facilitate reception of the lifeboat.

13. A method as claimed in any one of the preceding claims, wherein certain of the steps of the method are effectd by remote control, e.g. by a radio link, for example for the release of a sea anchor from the lifeboat.

14. A method of recovering survivors off-shore from a ship's lifeboat or the like as claimed in claim 1 and substantially as hereinbefore described.

15. A docking device for use in the method as claimed in any one of the preceding claims comprising a lifeboat support structure including a base and side members joined to the base to locate a lifeboat on the docking device, the support structure including an open end for reception of the lifeboat, buoyancy means, and adjustable means for holding the lifeboat on the support structure.

16. A docking device as claimed in claim 15, wherein the support structure is of open-work frame form.

17. A docking device as claimed in claim 15 or 16, wherein the device has means permitting folding or dismantling of the device.

18. A docking device as claimed in claim 16, wherein the support structure includes tubular members providing said buoyancy means.

19. A docking device as claimed in any one of claims 15 to 18, wherein the adjustable means comprises an inflatable device which is preferably remotely operable.

20. A docking device as claimed in any one of claims 15 to 19, wherein the support structure is fitted with guide means for the tow-line to the lifeboat.

21. A docking device as claimed in any one of claims 15 to 20, wherein the support structure is in the form of a sled with the base adapted for lower friction sliding movement on the deck of the rescue craft.

22. A recovery sled comprising a buoyant structure in the form of an open framework, adapted to slide off and on the deck of a suitably adapted ship over a sea moderating mat and to hold a lifeboat or similar survival craft within.

23 A docking device substantially as hereinbefore described with reference to and as illustrated in Fig. 8 of the accompany drawings.