WO2012053897A2

WO2012053897A2 - An arrangement and a crane assembly for deployment and/ or retrieval of a payload at sea, and a movement attenuation payload deployment and/ or retrieval device, and a snubber device.

Info

Publication number: WO2012053897A2
Application number: PCT/NO2011/000294
Authority: WO
Inventors: Per Erik ØSTBØ; Ilan Sharoni
Original assignee: Innova As
Priority date: 2010-10-19
Filing date: 2011-10-19
Publication date: 2012-04-26
Also published as: WO2012053897A3

Abstract

An arrangement for deployment of a payload onto a sea surface or into subsurface from a marine structure, and/or payload retrieval from the sea onto the marine structure. The system comprises a crane assembly for both horizontal and vertical translation of the payload, the crane assembly configured to be operatively and movably attached at an upper, first level and at a lower, second level to structures of the marine structure. The crane assembly has a) an upper part which is inclined relative to the horizontal, the inclination being adjustable, the upper part having a first pair of longitudinal beams and a reinforcing frame bridging the beams, and an upper end of the beams being movable along a rail system related to the first level structure by means of a controllable upper drive means, b) a lower part constituted by a second pair of beams or rails which at an outer end region thereof are linked to an outer end region of the upper part constituted by an outer end of the first beams of the upper part; and at the inner end region thereof is movable relative to said second level structure; and c) a payload deployment carriage controllably movable along the longitudinal beams of the upper part, wherein the carriage is associated with means for gripping and/or moving the payload. In a currently preferred mode, the crane assembly is operatively associated with a winch for wire, rope, wireline or umbilical for supporting and moving the payload. A pitch and roll movement attenuating snubber device is associated with the carriage.

Description

An arrangement and a crane assembly for deployment and/ or retrieval of a payload at sea, and a movement attenuation payload deployment and/ or retrieval device, and a snubber device. The present invention relates to an arrangement for deployment of a payload onto a sea surface or into sub-surface from a marine structure, and/ or payload retrieval of the payload back from the sea onto the marine structure, as defined in the preamble of claim 1. Although the general term "marine structure'^'' is used in the following description and the claims, it is appreciated that it could be:

a) any inshore or offshore installation ,

- b) any ship or any marine vessel, even a floating dock, which is movable or

stationary and located inshore or offshore or generally at sea, as well as

c) any marine related structure ashore, such as a port, a harbour, a pier, a quay or a dock.

Thus, the legal interpretation of the term "marine structure" in the description and the claims will encompass also such installations, ships or vessels, or marine related structures as just mentioned.

The following description will, as examples, be mostly related to the mentioned type b) of marine structure.

Further, the present invention relates to a movement attenuation payload deployment and/or retrieval device as defined in the preamble of claim 23, and a so-called "snubber" as defined in the preamble of claim 23 and 26.

Further, the present invention also relates to aspects of the crane assembly which forms part of the arrangement, as further defined in claims 29, 30 and 31.

Although the present invention is described in the context of deployment and/ or retrieval of mobile equipment, e.g. remotely operated vehicle (ROV), it may be used for other purposes, such as e.g. placing items or equipment on the surface or lowering items below sea surface, loading equipment onto or off from a supply ship, launching rescue or emergency service vessels onto the sea surface, and retrieval thereof. The field of use is not limited to these examples of mode of operation.

In the description to follow, there will be referred to a crane assembly hangar or framework onboard a marine structure , the hangar or framework for convenient understanding defining a "ceiling" and a "deck" thereof. However, it will be appreciated the hangar or framework will in general exhibit a top structure, such as e.g. a ceiling or frame part (with or without cover), and a bottom structure, such as e.g. a deck or a floor. Up to now, the prior art lifting devices for launching at sea mobile equipment over the side or from the stern of a marine structure, such as e.g.ship, has caused distribution of dynamic loads imposed onto the lifting device to be transferred to the vertical plane of the marine structure, so that deck or ceiling structures of the marine structure are exposed to high dynamic point loads, the overall area in question not necessarily being so large. Such devices have substantially used heavy duty A-type frames and ROV moonpool systems

(through the marine structure well) for high waves such as Hs5 (10 meters wave height). A standard marine structure deck is normally dimensioned for maximum 3 - 5 tons per square meter, suitable for launching equipment intended for sub-sea operations up to Hs3-Hs3.5 (6-7 meters of wave height). Exceeding these limits to e.g. Hs5 (i.e. from 7 to 10 meters of wave height) has required extra heavy duty A-frames and substantial structural

modification on the marine structures in order to distribute the dynamic loads to the structure of the marine structure in a safe manner.

Available, traditional A-frames exhibit a long distance from support location on the frame and down to the sea when handling the payload. This can easily yield pendulum movement on the payload, e.g. an ROV during lowering for deployment or upon retrieval, such movement being highly unwanted. If the distance of the payload from the marine structure is to be increased, the A-frame structure must be expanded or be angled. Such modification will cause even higher static and dynamic loads on the marine structure deck structure, by far exceeding loads which the deck structure can normally withstand.

In the following, the term umbilical is short for umbilical cable. The following description will, as examples, be mostly related to the mentioned type b) of marine structure.

Thus, in practise there are limits set to Hs3.5 (7 meters of wave height) for standard A- frames with an overall height of approx. 7- 9 meters because of a long pendulum arm in outer position (6-9 meters) down to sea level. Such a long pendulum arm easily yields that the payload or object to be lowered or lifted through the sea surface is banged into the side of the marine structure or touches the subsurface stability or propulsion means of the marine structure. Wire, rope, wireline or umbilical distance from the side of the marine structure at an extreme outer position is in the range 3 - 5 meters for a standard A-type frame. Further, the structure of traditional A-frames cannot withstand dynamic loads caused on the equipment when Hs values exceed Hs3 - Hs3.5 (6 - 7 meters of wave height) without being exposed for potensial overloads. The DAF (Dynamic Amplification Factor) on standard A-frames vary between 1.5 and 3, and hence standard A-frames will be overloaded if the dynamic loads exceed SWL (Safe Working Load)x DAF.

The weight of a typical robust A-frame for wave height Hs 3.5 to 5 is high, in the range 20- 40 tons, and the A-frame structure which is hinged yields an extremely high point load to be distributed on the marine structure deck. The downwardly extending forces to be distributed into the marine structure as well as the dynamic loads imposed to the A-frame design when the A-frame is in the outermost position, tilted down towards the water surface, will exceed 100 tons. The supporting deck structure must be strengthened to withstand such loads, and substantial rebuilding and reinforcements will accordingly be required. Upwardly action forces applied to the deck structure is over an area just a few square meters more than 100 tons. Thus, before installation of a rail operated A-frame, the deck structure must be substantially reinforced prior to installation. Rail equipped launching and retrieval systems are currently available with rail systems either on the marine structure deck or in the marine structure ceiling. Strengthened A-frames with a fixed hinge point allowing an "A-frame design" to obtain horizontal position

(approximately a 135° motion pattern) provide extremely high deck loadings.

The present invention therefore is intended to remedy the disadvantages of the prior art A- frames, and also provide a novel snubber device for attenuating shocks and/ or at least one of unwanted pitch and roll movements which yield unwanted pendulum movements of the payload.

Accordingly, the arrangement of the invention comprises:

- a crane assembly for both horizontal and vertical translation of the payload;

- a crane assembly hangar or framework onboard the marine structure with an opening in the hull or the framework of the marine structure and means for moving the crane assembly out of or into the hangar or framework; the hangar or framework having an upper, first level structure, e.g. a ceiling or frame part, and a lower, second level structure, e.g. a deck or a floor,

a rail system and rail guide system both related to and located at the first level structure of the crane assembly hangar or framework for controllably moving the crane assembly,

- a rail system and rail guide system both related to the second level structure of the crane assembly hangar or framework for controllably moving the crane assembly,

wherein the crane assembly comprises:

an upper part which is inclined to the horizontal, the inclination being adjustable, the upper part having a pair of longitudinal beams and a reinforcing frame bridging the beams, and an upper end of the beams being movable along the rail system related to the first level structure;

a lower part constituted by a pair of movable rails of said rail system related to the second level structure and linked at an outer end region thereof to an outer end region of the upper part constituted by a lower end of the beams of the upper part;

upper drive means for moving the upper end of the inclined beams of the upper part out of or into the hangar or the framework along the rail system related to the first level structure,

lower drive means for moving the rails of the lower part out of or into the hangar or the framework in slidable engagement with the rail guide system related to the second level structure,

a payload deployment carriage controllably movable along the longitudinal beams of the upper part, and wherein the carriage is associated with means for gripping and/or moving the payload.

Although the present specification specifically mentions the use of a hangar, it could be visualized to use a supportive framework on the aft deck of the marine structure instead. Such framework could least have a ceiling, and walls as well as gates or doors could also be provided for artic or tropical environments, thus providing a shield against cold or heat, a housing for air conditioning, and/or protecting crew, equipment and payload from prevailing weather, such as e.g. heavy wind, cold, heat, sleet, snow and rain.

The carriage may be provided with a locking device to be interactive with engagement means on the wire, rope, wireline or umbilical for gripping the payload during at least its horizontal movement. In general, it is a pre-requisite that the payload must be locked to the snubber or carriage during excursion until it reaches it preferred launch position, i.e. all the way out and all the way down, or vice versa.

There may be the situation where no wire, rope, wireline or umbilical is used, in which case the carriage has a controllable gripping device for engaging the payload when the carriage is not cooperating with a winch for handling a wire, rope, wireline or umbilical,

In the situation where a wire, rope, wireline or umbilical is used, then a winch is located in the crane assembly hangar, the framework or at adjacent marine structure space, the winch being configured to be linked to the payload deployment carriage and the payload by means of the wire, rope, wireline or umbilical.

In another variant of the arrangement, the carriage associated payload gripping means is a cradle or tray which is configured to enable deployment of a vessel onto the sea surface from the marine structure or and/ or retrieval of a vessel from the sea surface onto the marine structure. Suitably, the cradle or tray is in the form of a payload dedicated framework structure.

When operating with a wire, rope, wireline or umbilical, the carriage at an outer end is provided with a sheave over which said wire, rope, wireline or umbilical passes. In a particular mode, the sheave is movable in its axial direction, transversely of the longitudinal direction of the upper part, so that the payload is in fact not only movable in two dimension, but in a three-dimensional way. In currently preferred embodiment, a payload movement attenuation device or snubber is associated with the carriage. Currently, the payload movement attenuation device or snubber, as seen in direction from the winch to the payload, is located at the outer end of the carriage downstream of the sheave. In case the sheave is transversely movable, the payload movement attenuation device or snubber is movable transversely of the longitudinal direction of the upper part together with the sheave.

The device in a current embodiment exhibits a pair of pitch control means, yaw control means, roll control means, a latching device configured to secure the lifted payload at least during horizontal movement thereof, a sheave for supporting the wire, rope, wireline or umbilical which links with the winch and the payload, and a docking tray.

A first linking structure is provided to link the pitch control means to the yaw control means, and wherein a second linking structure is provided to link the roll control means to the pitch control means. Alternatively, a first linking structure is provided to link the pitch control means to the roll control means, and wherein a second linking structure is provided to link the roll control means to the yaw control means. Suitably, the pitch and roll control means each include electrically operated, sensor controlled motors which attenuate for any one of undesirable pitch and roll via a respective drive means.

Further, a shock attenuator or absorber device is provided, the device comprising a sheave over which said wire, rope, wireline or umbilical passes, the sheave interacting with a hydraulic cylinders and pressure accumulators, the hydraulic cylinders supporting the sheave in a frame attached to the hangar or framework ceiling, and the device being located between the winch and the carriage. The tilting angle of the upper part of the crane assembly and any tilting angle of the lower part of the crane assembly relative to the horizontal will be a function of mutual distance between the inner end regions the upper part and the lower part in a direction parallel to said ceiling and deck.

In one operational mode, the rails of the lower part are parallel to the bottom structure or deck, and the beams of the upper part form a set angle with the upper rails.

In another operational mode, the inner end region of the lower part is located inwardly of the opening and close thereto, the upper rails are in a position shifted towards the outside of the opening to have an outer region thereof outside the opening, and the upper end region of the beams of the upper part is also outside the marine structure hull, whereby the rails of the lower part are downwardly inclined. Thus a rearward end of the lower rails are in tiltable engagement with a forward slide shoe on the bottom structure or deck, the slide shoe having tiltable properties.

In a further operational mode, the inner end region of the lower part is located inwardly of the opening and close thereto, the upper rails are in a position inwardly of the opening, and the upper end region of the beams of the upper part is located inwardly of the opening and further away from the opening than the inner end region of the lower part, whereby the lower part is upwardly inclined. Thus a rearward end of the lower rails are in tiltable engagement with a forward slide shoe on the bottom structure or deck, the slide shoe having tiltable properties. In order to create structural stability to the carriage and thereby to the crane assembly, a reinforcement frame is bridging the longitudinal beams of the upper part.

Dependent on prevailing weather conditions, at least one door or gate is provided for partly or fully closing said opening when the crane assembly is located fully or partly inside the hangar or framework.

As indicated in the introduction, the invention also provides in general for a payload movement attenuation deployment and/or retrieval device, and the device comprises:

a payload deployment and retrieval carriage; a winch to be linked to the carriage and the payload by means of a wire, rope, wireline or umbilical,

- payload movement attenuation equipment associated with the carriage, said equipment comprising pitch control means and roll control means, - a yaw control means,

- a latching device configured to secure the lifted payload at least during

horizontal movement thereof,

a sheave for supporting the wire, rope, wireline or umbilical which links with said the winch and the payload,

- and a docking tray, and

wherein at least the pitch and roll control means each including electrically operated, sensor controlled motors, said pitch and roll control means configured to attenuate for any one of undesirable pitch and roll via a respective drive means.

Suitably, a first linking structure is provided to link the pitch control means to the yaw control means, and a second linking structure is provided to link the roll control means to the pitch control means. Alternatively, a first linking structure is provided to link the pitch control means to the roll control means, and wherein a second linking structure is provided to link the roll control means to the yaw control means.

In another aspect of the invention, the snubber device comprises: a payload deployment and retrieval carriage; payload movement attenuation equipment associated with the carriage, said equipment comprising a pair of pitch control means and roll control means, a sheave for supporting a wire, rope, wireline or umbilical which links a winch with the payload, and a docking tray. The inventive features relate to the pitch and roll control means each including electrically operated, sensor controlled motors, said pitch and roll control means configured to attenuate for any one of undesirable pitch and roll via a respective drive means.

In a further embodiment of the snubber device, the device comprises a yaw control means which is provided to enable rotation of the payload about an upright axis, wherein the yaw control means includes an electrically operated, sensor controlled motor. A latching device may be provided and configured to secure the lifted payload during at least some movement thereof.

In a specific aspect of the invention there is provided a crane assembly for deployment of a payload onto a sea surface or into subsurface from a marine structure, and/ or payload retrieval from the sea onto the marine structure, wherein the crane assembly is configured for both horizontal and vertical translation of the payload, wherein the crane assembly is configured to be operatively and movably attached at an upper, first level and at a lower, second level to structures of a hangar or a framework onboard the marine structure, and wherein the crane assembly has

o an upper part which is inclined relative to the horizontal, the inclination being adjustable, the upper part having a pair of longitudinal beams and a reinforcing frame bridging the beams, and an upper end of the beams being movable along a rail system related to the first level structure o a lower part constituted by a pair of movable rails at the second level structure , the lower part rails linked at an outer end region thereof to an outer, lower end region of the upper part constituted by a lower end of the beams of the upper part;

o upper drive means for moving the upper end of the inclined beams of the upper part along the rail system related to the first level structure, o lower drive means for moving the rails of the lower part in slidable engagement with a rail guide system related to the second level structure, and

o a payload deployment carriage controllably movable along the

longitudinal beams of the upper part, wherein the carriage is associated with means for gripping and/or moving the payload.

In a variant, there is provided a crane assembly for deployment of a payload onto a sea surface or into subsurface from a marine structure, and/ or payload retrieval from the sea onto the marine structure, wherein the crane assembly is configured for both horizontal and vertical translation of the payload, wherein the crane assembly is configured to be operatively and movably attached at an upper, first level and at a lower, second level to structures of the marine structure, and wherein the crane assembly has: an upper part which is configured to have adjustable inclination relative to the horizontal, the upper part having a first pair longitudinal beams and a reinforcing frame bridging the beams, and an upper end of the beams being movable along a rail system related to the first level structure

a lower part constituted by a pair of second beams which are at one end pivotally attached to an outside wall or hull of the marine structure at said second level and at an outer end region thereof linked to an outer end region of the upper part constituted by an outer end of the first beams of the upper part;

upper drive means for moving the upper end of the inclined beams of the upper part along the rail system related to the first level structure, and

a payload deployment carriage controllably movable along the longitudinal beams of the upper part, wherein the carriage is associated with means for gripping and/or moving the payload.

In a more general aspect of the invention, there is present a crane assembly for deployment of a payload onto a sea surface or into subsurface from a marine structure, and/ or payload retrieval from the sea onto the marine structure, wherein the crane assembly is configured for both horizontal and vertical translation of the payload, wherein the crane assembly is configured to be operatively and movably attached at an upper, first level and at a lower, second level to structures of the marine structure, and wherein the crane assembly has:

- an upper part which is inclined relative to the horizonatal or is configured to be moved to assume inclination relative to the horizontal, the inclination being adjustable, the upper part having a first pair of longitudinal beams and a reinforcing frame bridging the beams, and an upper end of the beams being movable along a rail system related to the first level structure by means of a controllable upper drive means,

a lower part constituted by a second pair of beams or rails which at an outer end region thereof is linked to an outer end region of the upper part constituted by an outer end of the first beams of the upper part; and at the inner end region thereof is movable relative to said second level structure, and a payload deployment carriage controllably movable along the longitudinal beams of the upper part, wherein the carriage is associated with means for gripping and/or moving the payload. In one, currently preferred embodiment, the crane assembly is operatively associated with a winch for wire, rope, wireline or umbilical for supporting and moving the payload.

Suitably, the carriage is provided with a locking device to be interactive with engagement means on the wire, rope, wireline or umbilical for gripping the payload during at least its horizontal movement.

The carriage may exhibit a controllable gripping device for engaging the payload when the carriage is not cooperating with a winch for handling a wire, rope, wireline or umbilical, Carriage associated payload gripping means may be a cradle or tray which is configured to enable deployment of a vessel onto the sea surface from the marine structure or and/ or retrieval of a vessel from the sea surface onto the marine structure. The cradle or tray is suitably in the form of a payload dedicated framework structure. The carriage at an outer end is suitably provided with a sheave over which said wire, rope, wireline or umbilical passes, and the sheave is movable in its axial direction, transversely of the longitudinal direction of the upper part.

The crane assembly may exhibit a payload snubber associated with the carriage and having pitch control means and roll control means, wherein yaw control means are provided on the snubber to enable rotation of the payload about a vertical axis. Preferably, at least the pitch and roll control means each include electrically operated, sensor controlled motors.

It will be appreciated that the invention provides a V- frame structure in a lying posture (as seen in side view), which has substantial structural advantages over the prior art A-frame structure, as will be explained furthermore in the description to follow below.

However, it will also be appreciated that the payload movement attenuation device could not only be used on a V-frame structure as specifically referred to in the present specification and drawings, but could be used, subject to some structural modifications on a currently used A-frame structure.

The invention is now to be further described, by way of example embodiments with reference to the attached drawings.

Figure 1 is a perspective view of a V- frame crane assembly fully retracted into a hangar on a marine structure. Figure 2 is a side view of the embodiment of Figure 1.

Figure 3 is an enlarged view of the crane assembly, without winch and connection therefrom to a carriage being shown. Figure 4a is a detailed side view of the ceiling rail system and ceiling rail guide system.

Figure 4b is a detailed perspective view of the ceiling rail system and ceiling rail guide system as shown on Figure 4a. Figure 5 is a detailed view of the ceiling associated rail system and the ceiling associated rail guide system, as related to the examples shown on Figures 7 - 15.

Figure 6 is a detailed view of the deck associated rail system and the deck associated rail guide system, as related to the examples shown on Figures 7 - 15.

Figure 7 shows the crane assembly partly extending through the hangar opening with the payload still inside the hangar.

Figure 8 shows the crane assembly fully extending through the hangar opening with part of the payload still inside the hangar.

Figure 9 shows the crane assembly fully extending through the hangar opening with the payload fully outside of the hangar and the hull of the marine structure, depending from a carriage which is partly driven along the crane assembly away from the hull. Figure 10 shows the crane assembly fully extending through the hangar opening with the payload fully outside of the hangar and the hull of the marine structure, depending from the carriage which is fully driven along the crane assembly away from the hull.

Figure 11 illustrates in enlarged view the state operation generally as shown on Figure 9.

Figure 12a shows the crane assembly fully extending through the hangar opening with the payload outside the hangar and the marine structure hull, depending from the carriage into the sea, the carriage being fully driven along the crane assembly away from the marine structure hull.

Figure 12b is a perspective view of figure 12a, and also shows details related to a pull load attenuation system located between the winch and the carriage.

Figure 13 shows the crane assembly partly extending through the hangar opening with the payload outside the hangar and the marine structure hull and submerged below sea surface, the payload fully submerged and depending from the carriage which is fully driven along the crane assembly to be at an outermost end of the crane assembly, and lower hangar door is closed to prevent wave inflow, and the V shaped frame is retracted as far as allowable towards the side of the marine structure for optimum payload motion attenuation purposes.

Figure 14 shows the crane assembly fully extending through the hangar opening with the payload outside the hangar and the marine structure hull, the payload depending from the carriage which is fully driven along the crane assembly to its outermost end, and the payload being partly submerged in the sea by telescoping out the upper rails.

Figure 15 shows the crane assembly partly extending through the hangar opening with the payload outside the hangar and the marine structure hull, the payload depending from the carriage which is driven along the crane assembly close to its outermost end, and the payload being above the sea surface by retracting the rear end of the upper part.

Figure 16 is a perspective detailed view from above and one side of the carriage with or without a snubber device. Figure 17 is a side view of the embodiment of figure 16 with a payload depending therefrom, to ensure constant angle relative to the vertical of the payload carrying wire, rope, wireline or umbilical by attenuating or controlling swaying or pendulum movement of the payload as caused by marine structure pitching movement. The geometry of the snubber ensures constant angle at the bullet, independent of snubber movement, whereby a completely passive feature is provided that is not related to any control machinery.

Figure 18 is a front view of the embodiment of figure 16, to ensure constant angle relative to the vertical of the payload carrying wire, rope, wireline or umbilical by attenuating or controlling swaying or pendulum movement of the payload as caused by marine structure rolling movement. The geometry of the snubber ensures constant angle at the bullet, independent of snubber movement, whereby a completely passive feature is provided that is not related to any control machinery.

Figure 19 illustrates non-snubber embodiment, viz. a sheave for a wire, rope, wireline or umbilical as located on a carriage of a crane assembly, possibly transversely movable. Figure 20 illustrates a movement attenuation device, a so-called "snubber" arranged on a carriage of a crane assembly and being transversely movable relative to the upper part of the crane assembly.

Figures 21a - 21d illustrates use of the crane assembly for deploying and retrieving a small vessel, e.g. a speed boat, a life boat or a rescue or special purpose boat.

Figures 22a - 22c illustrate a crane assembly framework structure for location on an upper aft deck of a marine vessel, Figure 22a showing the framework structure without any weather shield cover, Figure 22b showing the framework structure with roof and side wall covers and with a front opening and a side opening in an open state, and Figure 22c showing the framework structure with roof and side wall covers and with a front opening and a side opening in a closed state.

Figure 23 shows the snubber of the invention as applied to use on an A-type of frame. Figure 24a - 24e illustrate through simplified sketches in side view a modified embodiment of the crane assembly, according to the invention, shown -as example - in some operational modes, and Figure 24f is a perspective view of the modified embodiment.

In order to more fully appreciate stress imposed on a marine structure by an A - frame structure in contrast to the inventive V- frame structure, the following brief explanations and load diagrams are introduced. A) Structural load distribution caused by an A-frame (simplified), and

assuming base length and height of frame are equal

Case Al) Frame vertical, payload (P) attached to snubber:

Vertical load at fore base FBIV = P

Case A2) Frame vertical, payload suspended by wire

P

Vertical load at aft base FB₂V = P

Horizontal load at bases FBIH + FB₂H = FW= P

Case A3) Fully extended, payload attached to snubber:

B3V B3V

Vertical load at aft base FB₂V = P

Vertical load at fore base FB₂V = 2 X P

Case A4) Fully extended, payload suspended by wire:

Vertical load at aft base FB₂V = P

Vertical load at fore base FB₂V = 2 X P

Horizontal load at bases FBIH + FB₂H = F_w= P

B) Structural load distribution caused by a V-frame (simplified), assuming vertical spacing and extension of frame are equal

Case Bl) Payload attached to snubber:

P

Vertical load at upper base FR₂V = P

Horizontal load at upper base FB₂H = P

Horizontal load at lower base FBIH = P

Case B2) Payload suspended by wire:

Vertical load at upper base FB₂V = P

Horizontal load at upper base FB₂H = P

Horizontal load at lower base FBIH-FW+P = 2 XP Case B3) Frame tilted, payload attached to snubber:

Vertical load at upper base FB_2V = 3/8 X P

Vertical load at lower base FB₂V = 5/8 X P

Horizontal load at upper base FB₂H = 1.1 X P

Horizontal load at lower base FBIH = 1 -1 x P

Case B4) Frame tilted, payload suspended by wire:

Vertical load at upper base FB₂V = 0.2 X P

Vertical load at lower base FB₂V = 0.8 X P

Horizontal load at upper base FB₂H = 0.5 X P

Horizontal load at lower base FBIH = 1.5 X P

Upon a review of the force diagrams above, it may be concluded that a) unlike the A- frame structure, the V-frame structure is exposed to moderate bending forces. Also, the V- frame structure could yield reduced structure weight; b) wire, rope, wireline or umbilical adds average load, but reduces peak load; c) the higher the point where the wire, rope, wireline or umbilical enters the system, the less it adds to the load; d) vertical partitioning structures (floor and ceiling) can withstand higher loads at the horizontal plane than vertically; and e) actual load-distribution depends on geometry and stiffness of mounting structure. Thus, it may be concluded that once the payload leaves the snubber and hangs by wire, rope, wireline or umbilical, the horizontal load at the lower mounting point becomes 2 x P for the V-frame. This is twice the equivalent load at an A-frame. The wire, rope, wireline or umbilical will however absorb bursts, and the floor / deck can take more at this plan.

Once the structure is fully extended, the leverage arm of an A-frame will multiply the load at the base of the frame, depending on a length-ratio frame/base. At the V-frame the vertical load remains the unchanged, thus half the load in the example above.

Both a heavy duty A-frame and a V-frame will be able to release a payload from a snubber at about the same height above sea surface. Pendulum movements are therefore more or less the same. The advantage of a V-frame is that it is able to translate the wire/ rope/ wireline/ umbilical sheave farther away from the hull to reduce the risk of the payload colliding with the hull. A longer heavy dutyA-frame will load the marine structure more and will require a much higher hangar, unless the frame is made as an extendable structure.

The invention will now be described with reference to the attached drawing figures.

On figure 1 there is shown the sea level at a calm sea surface 1, a hull 2 of a marine structure, a crane assembly hangar 3, a hangar ceiling 4, upper (ceiling associated) rails 5, lower (deck associated) rails 6 forming lower part of the crane assembly, upper part 7 of crane assembly, and longitudinal beams 8 on the upper part 7 to serve as deployment rails for a carriage 9 controllably movable along the beams 8.

The carriage 9 may include in a preferred, yet not limiting embodiment include equipment for attenuating or controlling unwanted swaying or pendulum movements of the payload caused by external influence, and thereby also serving as a kind of shock and motion absorber upon movements of the payload. The carriage 9 also serves as a docking unit for a payload 10. In the example shown on figure 1, the payload 10 is typically an ROV 10' (Remotely Operated Vehicle) with TMS 10" and tooling skid 10"'.

Tether Management System (TMS) is a safe haven and an elevator for the ROV to and from an operational or work depth. Inside the TMS there is a sub-sea operative winch to manage the soft tether cable that provides electrical power and control for propulsion, links to sensors, and provisions for video and telemetry transmissions to and from the ROV. The cable will allow the ROV to make excursions at a depth of e.g. 200 - 1500 meters from the point of the TMS at operational or work depth.

A reinforcement frame 8' extends between and thus bridges the beams 8.

5' denote cut-outs in the hull for upper rails 5, and 6' denote cut-outs in the hull for rails 6 of the lower part of the crane assembly, i.e. the rails 6 which are movable along rail guides 12, the lower pair of rails 6 thus constituting the lower part of the crane assembly.

The working floor or deck of the hangar is denoted by 13, and the hangar floor or deck is denoted by 13'. On figures 1 and 12b, it is shown that the working floor 13 is at a level above the rails 6 forming the lower part. Thus, the working floor 13 could shield the rails 6 and prevents a person 14 from being accidentally injured when the crane assembly is caused to move out of the hangar 3 or into the hangar 3. However, in general the floor surface should be free of any obstrusions. Instead of the floor 13, a longitudinal inverted U profile (not shown) could cover each of the two rails 6, thus in some cases making quick access to the rails 6, if required. Alternatively, each rail 6 and an inverted, covering U- profile could be located along either side of the floor 13.

A wire, rope, wireline or umbilical 15 connects the payload 10 and the carriage 9 with a winch 16 via a shock absorber device 17, the device comprising a sheave 17' over which said wire, rope, wireline or umbilical 15 passes, the sheave 17' interacting with a frame 17" and hydraulic cylinders 17"' and pressure accumulators, the hydraulic shock attenuating or absorbing cylinders 17"' supporting the frame attachment to the hangar ceiling 4. The device 17 is located between the winch 16 and the carriage 9. The winch 16 should be in a constant tension mode of at least 2 tons when e.g. an ROV payload is latched to the carriage or snubber (if installed) and is passed horizontally out from the hull of the marine structure.

On figure 2 there is shown upper rail guides 11, upper drive means 7', 7" for moving the upper part 7 out of or into the hangar 3, and deployment drive means 9' for moving the carriage 9 along the beams 8. The drive means 7' drives the upper end of the carriage 9, i.e, upper, inner end of the beams 8 along the rails 5, whereas the drive means 7" is provided to displace the rails 5 relative to the rail guides 11, if required, such as e,g.

indicated on Figs. 5 and 14.

The crane assembly hangar deck has said pair of rails 6 cooperative with lower drive means 12' by means of which the rails 6 of the lower part are movable in slidable engagement with the rail guides 12. Although just a single pair of rail guides 12 has been shown, it will be appreciated that at least a further pair of rail guides 12 such as a pair of wheels or slide shoes could be present at the innermost position.

It is noted that the upper part 7 and the lower part 6 (formed by movable rails) form a mutual acute angle, so that a V-shape like structure is formed. The mutual angle may e.g. be 30° - 50°, preferably 42° - 47°, although other mutual angle values may be used depending on the lifted payload and the distance from the hull 2 and on a case-to-case demand.

A lower hangar door or gate 18 is shown on Figure 1. The door or gate 18 is suitably a sliding door or gate which in a retracted position is configured to fit into a recess or a pocket in the hull 2. An upper door or gate above the door or gate 18 is not shown, but can be of a structure similar to that of the door or gate 18 or could be configured as a roller gate. If weather conditions are rough, then at least the door or gate 18 may be required to be in closing position to prevent intrusion of water waves on the marine structure deck, provided that movement of payload does not prevent it. However, it the weather conditions are acceptable, the doors or gates may be in an open position, or even dispensed with, i.e. not installed on the marine structure. The crane assembly 7, 6 moves horizontally out of and into the hangar 3. As seen from figure 2 the carriage 9 is locked to the beams 8, and the payload 10 is hence firmly attached to the crane assembly and cannot move along the rails 8 unless powered to do so. Two sets of three, synchronized and controllable drive means 7', 7"; 12' will be able to move the crane assembly, whereas the drive means 9' move the carriage 9. The drive means 7', 7"; 12' suitably each have a rotary screw drive (not shown) extending the full length of the rails 5; 6 or just part thereof and co-acting with nut means (not shown) located at the one or more of the rail guides 11 , at slide shoes 8" at the rearward ends of beams 8, and at rail guides 12, respectively. The beams 8 and the rails 5; 6 have, as shown, drive means 7', 7"; 12' at one end, and e.g. nut means at said rail guide 11, said slide shoes 8" and said rail guides 12, respectively. The nut means could e.g. be replaced by a chain wheel or sprocket, and the screw drive could be replaced by a chain drive. Such screw drives is are conventional and has have for sake of clarity not been shown on the drawings. However, it will be appreciated that other types of drive means lie within the expertise of the expert in the art to select, e.g. a gear and racket arrangement or a gear and chain arrangement. For sake of simplicity on the drawings, the screw drive details or the latter mentioned arrangements are not shown. At an end of each Each rail 5 there is located two drive motors 7';7", i.e. one 7' to drive the rail 5 and one to drive the slide shoe 8 attached to the beam 8, and the rail 6 and beam 8 has one drive motor 12 at one end to drive a glider means through use of a screw or a chain. All movement of the structure as well as the carriage 9 is performed in this manner, i.e. with no other motors or drives present.

Thus , the carriage 9 will be able to move along the beams 8 using a pair of drive means, e.g. synchronized screws extending along the full length of the beams 8 and co-acting with a pair of nuts attached to the carriage 9. Other types of drive means are also possible. Figure 3 shows the crane assembly of Figures 1 and 2 in an enlarged view. Figure 4 shows the ceiling associated rail system and how the beams 8 are slidably connected to the rails 5 via the slide shoes 8". Further, the carriage 9 is slidably connected to the beams 8 by means of slide shoes 9". Figure 5 illustrates that it is possible to locate the upper part of the beams 8 inside the hull 2, i.e. inwardly of the gate opening, or outside the hull 2 by actuating the motors 7" to move the rails 5 to protrude out from the hull 2. This is made possible by the rails 5 being in slidable engagement with stationary slide shoes 11.

Further, from Figure 6 it is seen that the rails 6 are so configured that they are in slidable engagement with the slide shoes 12. By moving the rails 6 so that their rear ends are at the location of slide shoes 12, tilting of the rails will be possible, as specifically demonstrated on Figures 14 and 15.

Figure 7 shows the crane assembly partly extending through the hangar opening 3' with the payload 10 still inside the hangar 3.

Figure 8 shows the crane assembly fully extending through the hangar opening 3' with part of the payload still inside the hangar 3.

Figure 9 shows the crane assembly, here denoted by 7; 6 fully extending through the hangar opening 3' with the payload 10 fully outside of the hangar 3 and the hull 2, depending from the carriage 9 which is partly driven along the upper part 7 of the crane assembly away from the hull 2. The payload 10 is still above the surface of the sea 1. The carriage 9 can gradually move down along the beams 8 so that the payload 10 finally touches the sea 1 surface and is lowered into the sea water, as seen from figure 6. Thereby wave motion acting on the payload is gradually absorbed by movement attenuation equipment on the carriage 9. The equipment is to be described later with reference to figures 11 - 14. However, the payload motion is still somewhat limited to protect lower rails 6. As shown on Figures 9 and 11, the carriage 9, sometimes also called a "snubber" if movement attenuation equipment is present, has been moved approximately half-way along the beams 8 of the upper part 7. With the carriage 9 moved more than 50%, attenuation equipment snubber will allow a pendulum motion of the payload, so that if a sudden large wave hits the payload during the launching, the equipment will cause a "yield" and thereby create an attenuation effect. Thereby, large dynamic forces will not be applied to the system by the payload, e,g. an ROV.

When the payload 10 is in a position as shown on figure 10, the carriage and docking unit 9 can start to release the payload, so that the payload 10 is lowered subsurface, as seen from figures 12a, 12b and 13. When lowering the payload 10, it is important to observe that deployment of the carriage or snubber (if installed on the carriage) on the crane assembly and its height above the sea will contribute to sufficient clearance or space between the payload 10 and the hull 2 in rough sea, as indicated on figs. 12a, 12b.

As regards the situation as shown on Figure 10, the payload movement attenuation equipment (to be further described later) on the carriage or snubber will counteract and thereby attenuate unwanted payload movements, inter alia caused by pitching and rolling movements of the marine structure at sea, so that large dynamic forces are not applied to the payload, e.g. an ROV.

If the payload is an ROV system, the ROV system will move attenuate with the sea action on it, as lomg long as the TMS 10' is locked to the carriage or snubber 9. If, however, it is required that a ROV system is not partly in the sea during launching or retrieval, that can be solved as shown on figure 15.

Figs.12a and 12b illustrate a situation where a negative marine structure roll movement is approximately 12°. For sea conditions being HS 3.5 (6-7 meters of wave height) and Hs 5.5 (10-11 meters of wave height, there are wave elements having 20° - 40° departure from the main wave direction. Such wave elements can cause strong marine structure roll movements. As clearly shown by figures 12a and 12b, the present invention avoids that the payload 10, e.g. an expensive and damage sensitive ROV system, is banged into the marine structure hull or bilge keel. As observed from figure 13, once the payload 10 clears the hull 2, also depth-wise, the crane assembly can be partly retracted into the hangar 3 to reduce leverage on the crane assembly. The bottom hangar door 18 can slide upwards and the upper door (not shown) can be partly moved down or rolled down (if of a rolling door type). In any case, the bottom door 18 can be raised to closing position once the payload is outside the hangar or framework. Thereby, the hangar 3, the crew 14 and any equipment will be less exposed to weather and general conditions at sea.

As mentioned above, the normal distance from the main deck of the marine structure to the sea surface is approximately 2.5 - 4 meters. A sudden large wave may then hit the hangar and flow into the hangar if the door or gate 18 is of side- or top-hinged design. The reason is that it is impossible to partly close the hangar opening. In artic regions, such as the Norwegian Sea or Barents Sea, it may impossible to carry out sub-sea operations if it is not possible to partly close the hangar opening during performance of the sub-sea operations. This is possible with the present V-type structure, the V-type structure thereby has a substantial advantage over the A-type structure where such operation mode is not possible. The present V- frame type of structural design with its supportive framework used for an aft deck location on the marine structure, with a ceiling and wall is an original and novel solution for use where artic conditions, including any icing, prevail, i. e. conditions which traditionally present great challenges to marine operations in such regions of the world.

As shown on figures 14 and 15, it is seen that the crane assembly can be tilted by manipulating either the upper rails (see figure 14) or by moving the rear ends of the beams 8 into the hangar, while the rear ends of the rails 6 are located shortly inwardly of the hangar opening 3', as seen from figures 14 and 15, as well as Figure 6.

It will be appreciated that tilting angle of the upper part 7 of the crane assembly and any tilting angle of the lower part 6 of the crane assembly relative to the horizontal are a function of mutual distance between the inner end regions the upper part 7 and the lower part 6 in a direction parallel to said deck 13.

In one mode, as e.g. seen on figures 1 - 13, the lower part 6 is parallel to the deck 13, and the upper part 7 (e.g. the beams 8 thereof) forms a set angle a with the upper rails 5. The mutual angle between the upper part 7 and the lower part is also angle a.

As shown on Figure 14, the inner end region 6" of the lower part 6 is located inwardly of the opening 3' close thereto. The upper rails 5 are the in a position shifted towards the outside of the opening to have an outer region 5" thereof outside the opening 3'. Further, the inner end region of the upper part 7 , i.e. the rearmost end 8" of the beams 8, is also outside the hull 2, whereby the lower part 6 is downwardly inclined.

As previously mentioned, it is normally 2.5 -4 meters from the main deck of the marine structure to the sea surface. If it is required to install the present V-type structure one deck level higher, the distance down to the sea surface becomes approximately 3 meters more, i.e. 5.5 - 7 meters. The long distance to the surface is then reduced by tilting the V-type crane structure downwards. If not tilted in this way, there is the risk that the payload, e.g. a ROV system may hit or bounce into the hull 2 upon launching or retrieval. The rails 5 can be movable in slidable contact with the stationary slide shoes 11, so as to be moved slightly outside the hull, e.g. as seen on Figures 5 and 14, by means of drive means.

As shown on Figure 15, the inner end region 6" of the lower part is located inwardly of the opening 3' close thereto. Further, it is seen from e.g. Figure 11 that the slide shoe 12 is located inwardly of the opening 3' and has an upper part 12" which is tiltable relative to its lower part 12"'. The upper rails 5 are in a position inwardly of the opening 3'. The inner end region 8" of the upper part is located inwardly of the opening opening 3' and further away from the opening opening 3' than the inner end region 12" of the lower part 12, whereby the lower part 12 is upwardly inclined.

As shown in Figure. 14, the payload 10 can then be submerged or be kept dry above the sea surface, as shown on figure 10 15.

It will be appreciated that the particular geometry of the inventive V-shaped crane assembly will cause that vertical, dynamic loads applied to the assembly from the wire, rope, wireline or umbilical is distributed to the structure of the marine structure on the horizontal plane of the marine structure. The dynamic loads on the assembly is distributed on a total of four rails, two rails 5 mounted on the ceiling 4 and two rails 6 mounted on the deck or floor 13'.

The weight of the assembly is low, approximately 15 - 20 tons and thus comparable with the conventional A-type structure. When comparing the current V- structure with the A- structure, and in particular the heavy duty A-type structure, weighing 20 - 40 tons, then the necessity to reinforce the marine structure, e.g. a ship, in order to be able to operate at Hs5 has been reduced considerably.

The vertical dynamic loads imposed by the V- structure from mobile equipment or payload during operations will be considerably less than for the prior art A-type structures. When the inventive assembly is an outer position, the payload 10, e.g. ROV, has a considerable distance of 8 - 12 meters from the hull 2. If a corresponding distance from the hull 2 were to be obtained with an A-type design, the payload hangar would have to be higher (an extra deck level). That implies that A-structure would have required 12 meters of free height, i.e. 4 deck levels, whereas the inventive V- structure only requires 3 deck levels or 8.5 - 9 meters.

When a V- structure shifts a payload 8 - 12 meters away from the hull 2, the possibility to accidentally damage the equipment by banging against the hull 2, as the case is with an A- type design. Although the pendulum movement will essentially the same, irrespective of V-structure or A-structure, the payload will be farther away from the hull 2 when using a V- frame. Such a pendulum movement could, however, actually be more severe with a longer arm, but the risk of the payload hitting any objects is substantially reduced. Due to its more flexible properties as regards wave height, effective operations at sea could at least be increased by 5 - 10% on a yearly basis, which yield that the inventive V-type design is substantially more cost-effective as regards operations at sea, and has

substantially lesser weight than the A-type design, thus yielding a cheaper structure.

The invention is now to be described with reference to figures 16 - 18.

The carriage 9 has so far been described without going into much detail about the movement attenuation device which can be associated with the carriage. The device exhibits pitch control means 19, yaw control means 20, and roll control means 21. Both the pitch control means 19 and the roll control means 21 have two drive means each. A sheave 22 is provided for supporting the wire, rope, wireline or umbilical 15 which links with the winch 16 and the payload 10, and a docking tray 23. An additional sheave or roller may be used to make certain that the wire, the rope, the wireline or the umbilical 15 is off the structure at all times, apart from passing over the sheave 22 and down through an opening in the docking tray. A first linking structure 24 is provided to link the pitch control means 19 to the yaw control means 20. A second linking structure 25 is provided to link the roll control means 21 to the pitch control means 19. 26 denotes a deployment device interface structure. Alternatively, a first linking structure is provided to link the pitch control means 19 to the roll control means 21, and wherein a second linking structure is provided to link the roll control means 21 to the yaw control means 20. A V- type structure related carriage 9 is shown. If a similar structure is to be used for an A-type structure, then a re-design will be required. An inboard roll actuator 21 is also shown. It may be smaller than the outboard actuator 21 to get sufficiently clear off the wire, rope, wireline or umbilical 15.

The pitch and roll actuators 19; 21 are shown with a single motor slew-drive, although a multi-motor slew-drive will be introduced where this drive will not be sufficient

A docking lock 27 is also provided. A rotary disc 27' with a keyhole 27" will make it possible for ROV system use to temporarily secure an ROV or TMS bullet to the carriage or snubber during horizontal transfer from inboard to outboard position, and possibly also vertically further down the inclined part of the crane assembly, thus allowing the umbilical to have low tension during the transfer. The pile or assembly 10 of e.g. ROV 10', TMS 10" and tooling skid 10"' must be locked to the snubber at all time when translated both "diagonally", i.e. horizontally and vertically. The frame and/or carriage can however be translated when the payload 10 is located deeper than the hull 2. It will be appreciated from the present description and the accompanying drawings, that the snubber has as a main task to avoid the payload hitting the hull 2 when the carriage 9 with its snubber has been moved to its outermost location and the payload 10 hangs by the wire, rope, wireline or umbilical 15.

The pitch, yaw and roll control means 19; 20; 21 each include electrically operated, sensor controlled motors 19'; 20'; 21' which adjustably control for any one of undesirable pitch, yaw and roll via a respective slew drive, such as slew drives 19" and 21", the slew drive 20' for the yaw not being visible on figure 11, only on figures 12 16, 17, 18 and 13 21.

The "snubber" 9 has the movement attenuation means related to pitch and roll as just described. Further, the snubber will function as a docking device for deck-to-water deployment and retrieval system. Figures 16 - 18 show a snubber designed to accompany a V-type structure as described for figures 1 - 10 for ROV-operations. The snubber can however be used at other handling systems.

As indicated above, the snubber is hinged about two perpendicular axes: roll on a horizontal axis sharing a plane with the wire 15, and pitch coaxial with the wire sheave 22. Motion of the snubber generates power (electrical or hydraulic) at the actuators. The power can then be dispatched as heat at a control unit up the line (not shown). The power flow can also be reversed: the alignment of the payload 10 can be manipulated by the actuators 19', 20' and 21'. Snubber locking can be achieved either by applied power or by local motor-brakes or by enclosed reduction gear box brakes.

Roll is limited by the outer structure 21. Pitch is limited by the structure and the exit-line of the wire 15. If pitching becomes excessive, then there is of course a risk that the payload 10 may collide with the hull 2. The roll of a marine structure at sea constantly lifts and lowers the point where the wire, rope, wireline or umbilical is suspended by the crane. This motion loads the wire, rope, wireline or umbilical and makes it difficult for a payload such as an ROV to leave and return to the TMS. The present inventive launch and recovery system can do nothing about the roll of the ship, but can compensate for it. The system will be equipped with a control unit that will operate the winch to wind and unwind to compensate for the roll of the marine structure at sea.

Entering and leaving the sea-surface, a sudden move of the payload can send a jerk along the wire. The device 17 above the winch is thus designed to protect the operating chain, i.e. winch wire bullet.

Interacting with waves, wind and motion of the marine structure, the payload will swing. This is actually a wanted motion as long as the payload is not oscillating or hitting other objects. The snubber will attenuate the swing and to some degree may also absorb shocks.

The docking unit will be interchangeable and custom-designed to given applications. The docking unit will be mounted underneath a slew drive 23 to achieve the yaw axis. Rotation will be limited only if imposed by the particular docking unit. The device as shown and described with reference to figures 16 - 18 is thus based on dynamic stabilization of the payload related to any pitch and roll thereof. Any pitch and roll movements of the payload causes by pitch and roll movements of the marine structure are attenuated, so that the payload is level. Thus, the payload wire 15 is kept level, despite any pitch and roll movements, thus preventing that the load accumulates pendulum movements of high energy.

A motion reference unit MRU (not shown) may exhibit sensors to control the operation of the actuators 19' and 21' in particular via a control system (not shown). Such a control system can monitor dynamic motion and control required speed, drive torque and position on the electrical motors 19' and 21' as well as 20' to maintain required orientation of the payload. Suitably, each motor may be provided with a sensor (not shown) that is configured to count motor revolutions or increments thereof. That will provide for precise measurement of actual alignment of each axis. Computerized translation of measurement data will yield virtual geometry which can then be measured against a virtual space. A dedicated software will enable calculation of most effective input to the motors to prevent collisions or to attenuate or prevent oscillations. If the dynamic forces exceed the motor capacities, the payload may be allowed to move relative to a vertical reference, but the energy of the oscillation will be managed by the electrical drive system. Frequency converters will be used for powering the motors and the encoders (sensors) reading the various axis positions of the snubber.

A key feature of the snubber are that shocks are absorbed by electrically operated rotary actuators 19 - 21. A further feature is that the snubber will utilize slew drives at most or all axes including the docking lock. According to a further feature, the snubber will utilize electrical motors to absorb energy and control the drive. These are, however, design features, not concept requirements. To this extent, it is feasible that a client can just as well acquire a hydraulically operated snubber. However electrical operation is the currently preferred mode of operation, simply because it is essential for operations in

environmentally sensitive sea regions where typically a "green certificate" is required, such at close to Lofoten, Norway and in the Barents Sea. Accordingly, no hydraulically operated equipment will be located exterior of the hull 2. The expert in the art will appreciate that the carriage 28, as seen on Figure 19, does not need to have a movement attenuating snubber, but merely a sheave 29 over which the wire, rope, wireline or umbilical can pass, and possibly with a locking means (not shown) to keep the payload in place during the horizontal movement of the crane assembly. Such a type of a locking device 27 is present on Figure 16 to be interactive with engagement means on the wire, rope, wireline or umbilical for gripping the payload during at least its horizontal movement. As appreciated from viewing Figure 19, the payload deployment carriage 28 is controllably movable along the longitudinal beams 8, and the carriage 28 should at least exhibit said sheave 29. As indicated by arrows, the sheave 29 is rotatable and could be, subject to a structural modification relative to what is shown on Figure 19, movable in its axial direction, transversely of the longitudinal direction of the upper part 7 of the crane assembly. This would imply using bars 28', 28" of the carriage 28 as slide bars and modifying the casing 29 Of the sheave 29 to exhibit slide tubulars. In such a case, the sheave can be controllably moved by drive means (not known) transversely of the upper part, thus enabling three dimensional movement of a payload.

With reference now to Figure 20, in case the carriage 9 employs a snubber of a type as described in the context of Figures 16 - 18 the payload movement attenuation device or snubber is movable transversely of the longitudinal direction of the upper part 7 together with the sheave 22. As seen, snubber 9 is slidably along transverse rails 30 by means of slide shoes 31, the transverse rails 30 forming with the slide shoes 9" a snubber "wagon" 32 which is slidable along the beams 8 by means the slide shoes 9". Motors 33 will enable the wagon 32 to be transversely movable. As mentioned earlier, the carriage 9 may have a controllable gripping device for engaging the payload when the carriage is not cooperating with a winch for handling a wire, rope, wireline or umbilical. Such situation could be as e.g. explained in the context of Figures 21a - 2 Id. The carriage associated payload gripping means 34 is a cradle or tray which is configured to enable deployment of a vessel 35 onto the sea surface 1 from the marine structure 36 and/ or retrieval of a vessel 35 from the sea surface 1 onto the marine structure 36 of any type a) , b) or c) as defined in the introduction. The cradle or tray is in the form of a payload dedicated framework structure 34.

Figures 22a - 22c illustrate a crane assembly framework structure 37 for location on an upper aft deck 38 of a marine structure. A winch 16 is provided, and the other Figure 22a shows the framework structure without any weather shield cover. Figure 22b shows the framework structure 37 with roof 39 and side wall covers 40 and with a front opening 41 and a side opening 42 in an open state, and Figure 22c shows the framework structure with roof 39 and side wall covers 40 and with the front opening closed by a roller gate 43 and a gate 44 in the side opening, both in a closed state.

Figure 23 shows the snubber 9 of the invention as described in connection with Figures 16 - 19 in particular, and as applied to use on an A-type of frame 45. Some modifications to the framework of the snubber will be required. The device exhibits a pair of pitch control means 46, 46' , yaw control means (not visible) , and roll control means 47, 47'. A sheave 48 is provided for supporting a wire, rope, wireline or umbilical 49 which links with a winch and a payload, and a docking tray 50. An additional sheave or roller may be used to make certain that the wire, the rope, the wireline or the umbilical 49 is off the structure at all times, apart from passing over the sheave 48 and down through an opening in the docking tray. The pitch and roll actuators 46,46'; 47, 47'are shown with a single motor slew-drive, although a multi-motor slew-drive will be introduced where this drive will not be sufficient.

However, it may be envisaged that no winch with associated wire, rope, wireline or umbilical may be required if the payload or the object to be handled is of a kind that is simply to be gripped by gripping means, e.g. docking station or yoke, on the carriage. If the carriage has just a sheave and no docking station, the carriage must cooperate with the winch so that when the crane assembly moves, the payload is kept at the carriage through static and dynamic tension on the wire, rope, wireline or umbilical to which the payload is attached. Still a further feature is that motion of the docking unit does not affect the angle of the wire in respect to the locked payload.

When the crane assembly is tilted, as shown on figures 14 and 15, a zero point of the snubber is shifted proportionally to tilt movement of the V-structure, so that the payload, e.g. ROV is in a level position. Encoders located at the four rails enable such

measurements.

With reference to Figure 12b, some comments will be awarded to the sheave system 17 which is related to an umbilical pull action load attenuation system connected to a payload umbilical winch system 16. The system has an accumulator and a shut-off valve to block the circuit between the cylinders 17" and the accumulators. This is not an active hydraulic circuit with pump an fluid tank. The cylinders have means for position control of the cylinder operation. The cylinders have counter-pressure from the accumulators, so that they cannot telescope before the load on the umbilical exceeds maximum permitted loading (SWL). High frequency pulls are easily compensated, due to low mass of the cylinders 17". If the loading on the system 17 increases about halfway, e.g. approximately 50% stroke of the pistons, the winch will roll off wire, rope, wireline or umbilical. If almost fully extended, i.e. approximately a 90 % stroke, that will trigger the winch to pay out wireline /umbilical at full speed to avoid overloading of the wire, rope, wireline/ umbilical. The shut-off valve blocks the circuit between the cylinders and the

accumulators, the valve blocking a circuit for active heave compensation or when user defined length of umbilical down to a certain depth of the payload has been delivered from the winch (large sea depths).

A modified version of the crane assembly and the arrangement thereof is shown on Figures 24a - 24f.

All structural details related to the upper part 7 of the crane assembly, the upper, first level rails 5, rail guides 11, as well as drives 7'; 7"; 9', the carriage 9, the beams 8, the frame 8'; the winch 16, the sheave 17 and its parts 17', 17" and the wire 15 are all structural elements which normally will not need any modification, and the explanation of their function and interrelationship is the same as already described, and the explanation thereof will therefore not be repeated. An easy reference is the comparative viewing of Figures 12b and 24f.

Further, the doors 18 will have a similar function, as will be appreciated when viewing Figure 24f.

However, it will be noted from viewing Figures 24a - 24e that the slide shoes 8" of the previous embodiment will need a modification, as the upper part 7 will assume a horizontal posture or almost horizontal posture when fully inside the hangar or the framework space 3, as shown on Figure 24a. The slide shoes 51 thus replacing slide shoes 8" are therefore extended downwards with sufficient distance to enable the frame 8' and the carriage 9 with snubber to have sufficient space from uppermost region of the space 3, e,g. the ceiling of the hangar.

It is noted that also in this modified embodiment, the upper part 7 has an inclination which is adjustable. As in the previously described embodiment, the upper part 7 has the first pair of longitudinal beams 8 and the reinforcing frame 8' bridging the beams. The upper end of the beams 8 is movable along the rail system 5 related to the first level structure, e.g. the ceiling of the hangar. The lower part is constituted by a pair of second beams 52 which are at one end 52' pivotally via a bracket 53 attached to the outside wall or hull 2 of the marine structure at said second level 54. At an outer end region 52" of the beams 52 they are pivotally linked to an outer end region of the upper part 7 constituted by an outer end 8"' of the first beams 8 of the upper part. A pivot bracket 55 suitably links the beams 8 and 52. In a currently preferred embodiment of the beams 52, it is noted that they are angled at a location 52"'. Such angled beam 52 is not a pre-requisite, but may be preferred in case the hangar is not so deep as to be able to accommodate the entire upper part 7. Thus, when the upper part has been moved as far as possible into the hangar or framework, the part of the beams between locations 52' and 52"' will lie along the hull 2. If the hangar depth is sufficient to fully accommodate the upper part 7, then the beams 52 can be rectilinear or even angled inwardly towards the space 3

Claims

1. An arrangement for deployment of a payload onto a sea surface or into subsurface from a marine structure, and/ or payload retrieval from the sea onto the marine structure, the arrangement comprising:

a crane assembly for both horizontal and vertical translation of the payload; a crane assembly hangar or framework onboard the marine structure with an opening in the hull or the framework of the marine structure and means for moving the crane assembly out of or into the hangar or framework; the hangar or framework having an upper, first level structure, e.g. a ceiling or frame part, and a lower, second level structure, e.g. a deck or a floor,

- a rail system and a rail guide system both related to and located at the first level structure of the crane assembly hangar or framework for controllably moving the crane assembly,

a rail system and a rail guide system both related to the second level structure of the crane assembly hangar or framework for controllably moving the crane assembly,

wherein the crane assembly comprises:

2. The arrangement according to claim 1, wherein the carriage is provided with a locking device to be interactive with engagement means on the wire, rope, wireline or umbilical for gripping the payload during at least its horizontal movement.

3. The arrangement according to claim 1, wherein the carriage has a controllable gripping device for engaging the payload when the carriage is not cooperating with a winch for handling a wire, rope, wireline or umbilical,

4. The arrangement according to claim 1 or 2, wherein a winch is located in the crane assembly hangar, the framework or at adjacent marine structure space, and wherein the winch is configured to be linked to the payload deployment carriage and the payload by means of a wire, rope, wireline or umbilical.

5. The arrangement according to claim 1, wherein the carriage associated payload gripping means is a cradle or tray which is configured to enable deployment of a vessel onto the sea surface from the marine structure or and/ or retrieval of a vessel from the sea surface onto the marine structure.

6. The arrangement according to claim 5, wherein the cradle or tray is in the form of a payload dedicated framework structure.

7. The arrangement according to claim 4, wherein the carriage at an outer end is provided with a sheave over which said wire, rope, wireline or umbilical passes.

8. The arrangement according to claim 7, wherein the sheave is movable in its axial direction, transversely of the longitudinal direction of the upper part.

9. The arrangement according to any one of claims 1, 2, 4 and 7, wherein a payload movement attenuation device or snubber is associated with the carriage.

10. The arrangement according to claims 7 and 9, wherein the payload movement attenuation device or snubber, as seen in direction from the winch to the payload, is located at center region of the carriage.

11. The arrangement according to claims 7, 8, 9 and 10, wherein the payload movement attenuation device or snubber is movable transversely of the longitudinal direction of the upper part together with the sheave.

12. The arrangement according to claim 9, 10 or 11, wherein said device exhibits a pair of pitch control means, yaw control means, roll control means, a latching device configured to secure the lifted payload at least during horizontal movement thereof, a sheave for supporting the wire, rope, wireline or umbilical which links with the winch and the payload, and a docking tray.

13. The arrangement according to claim 7, wherein a first linking structure is provided to link the pitch control means to the yaw control means, and wherein a second linking structure is provided to link the roll control means to the pitch control means.

14. The arrangement according to claim 7, wherein a first linking structure is provided to link the pitch control means to the roll control means, and wherein a second linking structure is provided to link the roll control means to the yaw control means.

15 . The arrangement according to any one of the claim 12, 13 or 14, wherein the pitch and roll control means each include electrically operated, sensor controlled motors which attenuate for any one of undesirable pitch and roll via a respective drive means.

16. The arrangement according to any one of claims 1, 2 and 4 - 15 , wherein a shock attenuator or absorber device is provided, the device comprising a sheave over which said wire, rope, wireline or umbilical passes, the sheave interacting with a hydraulic cylinders and pressure accumulators, the hydraulic cylinders supporting the sheave in a frame attached to the hangar or framework top structure, and the device being located between the winch and the carriage.

17. The arrangement according to any one of claims 1 -16, wherein the tilting angle of the upper part of the crane assembly and any tilting angle of the lower part of the crane assembly relative to the horizontal are a function of mutual distance between the inner end regions the upper part and the lower part in a direction parallel to said top structure and bottom structure.

18. The arrangement according to claim 17, wherein in one operational mode the rails of the lower part are parallel to the bottom structure, and wherein the beams of the upper part form a set angle with the upper rails.

19. The arrangement according to claim 17, wherein the inner end region of the lower part is located inwardly of the opening and close thereto, wherein the upper rails are in a position shifted towards the outside of the opening to have an outer region thereof outside the opening, and wherein the upper end region of the beams of the upper part is also outside the marine structure hull, whereby the rails of the lower part are downwardly inclined.

20. The arrangement according to claim 17, wherein the inner end region of the lower part is located inwardly of the opening and close thereto, wherein the upper rails are in a position inwardly of the opening, and wherein the upper end region of the beams of the upper part is located inwardly of the opening and further away from the opening than the inner end region of the lower part, whereby the lower part is upwardly inclined.

21. The arrangement according to any one of claims 1 -20, wherein a reinforcement frame is bridging the longitudinal beams of the upper part.

22. The arrangement according to any one of claims 1 -21, wherein at least one door or gate is provided for partly or fully closing said opening when the crane assembly is located fully or partly inside the hangar or framework.

23. A payload movement attenuation deployment and/ or retrieval device for use in deployment of a payload onto a sea surface or into subsurface, and retrieval of the payload back, the device comprising:

a payload deployment and retrieval carriage; - a winch to be linked to the carriage and the payload by means of a wire, rope, wireline or umbilical,

payload movement attenuation equipment associated with the carriage, said equipment comprising a pair of pitch control means and roll control means, - a yaw control means,

a latching device configured to secure the lifted payload at least during horizontal movement thereof,

- and a docking tray, and

- wherein at least the pitch and roll control means each including electrically operated, sensor controlled motors, said pitch and roll control means configured to attenuate for any one of undesirable pitch and roll via a respective drive means.

24. The device according to claim 23, wherein a first linking structure is provided to link the pitch control means to the yaw control means, and wherein a second linking structure is provided to link the roll control means to the pitch control means.

25. The device according to claim 23, wherein a first linking structure is provided to link the pitch control means to the roll control means, and wherein a second linking structure is provided to link the roll control means to the yaw control means.

26. A snubber device for use in deployment of a payload onto a sea surface or into subsurface, and retrieval of the payload back, the device comprising:

a payload deployment and retrieval carriage;

payload movement attenuation equipment associated with the carriage, said equipment comprising a pair of pitch control means and roll control means, a sheave for supporting a wire, rope, wireline or umbilical which links a winch with the payload,

and a docking tray,

the improvement wherein pitch and roll control means of the snubber device each including electrically operated, sensor controlled motors, said pitch and roll control means configured to attenuate for any one of undesirable pitch and roll via a respective drive means.

27. The snubber device according to claim 26, further comprising a yaw control means is provided to enable rotation of the payload about an upright axis, wherein the yaw control means includes an electrically operated, sensor controlled motor.

28. The snubber device according to claim 25, 26 or 27, further comprising a latching device configured to secure the lifted payload during at least some movement thereof.

29. A crane assembly for deployment of a payload onto a sea surface or into subsurface from a marine structure, and/ or payload retrieval from the sea onto the marine structure, wherein the crane assembly is configured for both horizontal and vertical translation of the payload; wherein the crane assembly is configured to be operatively and movably attached at an upper, first level and at a lower, second level to structures of a hangar or a framework onboard the marine structure, and wherein the crane assembly has:

o upper drive means for moving the upper end of the inclined beams of the upper part along the rail system related to the first level structure, o lower drive means for moving the rails of the lower part in slidable

engagement with a rail guide system related to the second level structure, and

o a payload deployment carriage controllably movable along the

30. A crane assembly for deployment of a payload onto a sea surface or into subsurface from a marine structure, and/ or payload retrieval from the sea onto the marine structure, wherein the crane assembly is configured for both horizontal and vertical translation of the payload; wherein the crane assembly is configured to be operatively and movably attached at an upper, first level and at a lower, second level to structures of the marine structure, and wherein the crane assembly has:

o an upper part which is configured to have adjustable inclination relative to the horizontal, the upper part having a first pair of longitudinal beams and a reinforcing frame bridging the beams, and an upper end of the beams being movable along a rail system related to the first level structure,

o a lower part constituted by a pair of second beams which are at one end pivotally attached to an outside wall or hull of the marine structure at said second level and at an outer end region thereof linked to an outer end region of the upper part constituted by an outer end of the first beams of the upper part;

o upper drive means for moving the upper end of the inclined beams of the upper part along the rail system related to the first level structurre, and

o a payload deployment carriage controllably movable along the

31. A crane assembly for deployment of a payload onto a sea surface or into subsurface from a marine structure, and/ or payload retrieval from the sea onto the marine structure, wherein the crane assembly is configured for both horizontal and vertical translation of the payload; wherein the crane assembly is configured to be operatively and movably attached at an upper, first level and at a lower, second level to structures of the marine structure, and wherein the crane assembly has:

o an upper part which is inclined relative to the horizonatal or is

configured to be moved to assume inclination relative to the horizontal, the inclination being adjustable, the upper part having a first pair of longitudinal beams and a reinforcing frame bridging the beams, and an upper end of the beams being movable along a rail system related to the first level structure by means of a controllable upper drive means, o a lower part constituted by a second pair of beams or rails which at an outer end region thereof are linked to an outer end region of the upper part constituted by an outer end of the first beams of the upper part; and at the inner end region thereof is movable relative to said second level structure, and

o a payload deployment carriage controllably movable along the

32. The crane assembly according to claim 29, 30 or 31 , wherein the crane assembly is operatively associated with a winch for wire, rope, wireline or umbilical for supporting and moving the payload.

33. The crane assembly according to claim 29, 30, 31 or 32, wherein the carriage is provided with a locking device to be interactive with engagement means on the wire, rope, wireline or umbilical for gripping the payload during at least its horizontal movement.

34 The crane assembly according to claim 29, 30 or 31 , wherein the carriage has a controllable gripping device for engaging the payload when the carriage is not cooperating with a winch for handling a wire, rope, wireline or umbilical,

35. The crane assembly according to claim 29, 30, 31 or 32 wherein the carriage associated payload gripping means is a cradle or tray which is configured to enable deployment of a vessel onto the sea surface from the marine structure or and/ or retrieval of a vessel from the sea surface onto the marine structure.

36. The crane assembly according to claim 35, wherein the cradle or tray is in the form of a payload dedicated framework structure.

37. The crane assembly according to claim 29, 30, 31 or 32 wherein the carriage at an outer end is provided with a sheave over which said wire, rope, wireline or umbilical passes, and wherein the sheave is movable in its axial direction, transversely of the longitudinal direction of the upper part.

38. The crane assembly according to any one of claims 29 -37, comprising a payload snubber which is associated with the carriage and having pitch control means and roll control means, wherein yaw control means are provided on the snubber to enable rotation of the payload about a vertical axis.

39. The crane assembly according to claim 38, wherein at least the pitch and roll control means each include electrically operated, sensor controlled motors.