EP0935552B1

EP0935552B1 - Multi-hull vessel

Info

Publication number: EP0935552B1
Application number: EP97912578A
Authority: EP
Inventors: Per I. Hagen
Original assignee: Cob Line International AS
Current assignee: Cob Line International AS
Priority date: 1996-11-05
Filing date: 1997-10-31
Publication date: 2002-03-20
Anticipated expiration: 2017-10-31
Also published as: WO1998019905A1; NO301703B1; AU4970897A; ATE214675T1; NO964680A; EP0935552A1; DE69711205D1; NO964680D0

Abstract

Multi-hull vessels (1) of the type in which the hulls (2, 3) are united in forward part of the vessel and in which a combined bottom and deck arrangement (4) join together and cover the area between the hulls (2, 3) from the place where they are united together and aftwards. The combined bottom and deck arrangement (4) is hinged in the forward part of the vessel through a transverse hinged arrangement (6) and supported inside in both mentioned hulls (2, 3), of which the bottom/deck arrangement (4) can be lowered at the vessel's aft end and turned via the hinged arrangement (6) towards the vessels bottom area.

Description

The invention is a multihull vessel of the type in which the hulls are united to form a mono hull forward and in which a combined bottom and deck arrangement are binding together and are covering the area between the hulls from where the hulls are connected together and aftwards.

The vessel according to the invention is preferably designed for transport, lifting and submerging of heavy goods from sea surface or the vessel down to great sea depths. Further the vessel is intended for lifting/rescuing of heavy constructions from seabed and up to sea surface and/or onboard the vessel and securing the same for further transportation in the vessel. The vessel can further be used for removing of for example offshore installations in the North Sea and other Ocean areas. The vessel can also be used for rescue operations in connections with accidents and or total loss.

Today there are no such vessels that can undertake such operations within the above-mentioned field of operations. The biggest crane vessel in operation today has a maximum lifting capacity of about 14.000 Tonnes (tandem-lift) which is considerably below the lifting capacity of subject invention, which has a lifting capacity in the range of 15.000 Tonnes. When it comes to existing crane vessels, it means lifting capacity from vessel to sea surface and from sea surface to vessel. The possibility for lifting below sea surface down to sea bed is limited for such vessels. The crane vessels in service today are further only limited to undertake the lifting operation, but in no greater extent to transport objects, and these must therefore be transferred and transported on vessels or barges.

The vessel itself according to the described invention is based on well known technology as a vessel of catamaran type with two connected hulls in which the connection has been made in the forward part of the vessel. Between the hulls it is known to have a fixed bottom/deck arrangement which binds the decks together and covers the area between the hulls.

The multihull vessel according to the invention has a flexible/turnable bottom construction. A turnable stabilizing device for a marine construction is described in NO-A-891017. This publication concerns a stabilizing device for a semi-submersible marine design. The stabilizing device according to this publication is used primarily in order to increase the marine designs stability. The turnable stabilizing device has according to the publication also another task and are used on one type of marine designs which should not be directly compared with the multihull vessel according to subject invention.

NO 173.052 concerns a multihull vessel in which an opening in the transverse deck is arranged. The flaps are turnably arranged, and are controlled by means of hydraulic cylinders.

From SE 434.629 it is known to use transport conveyor for collecting cargo. The conveyor is partly height-and lowerably mounted in the vessel. It is at it's upper end tumably mounted around an axis, transversally of the vessels longitudinal direction and substantially horizontal.

For the multihull vessel according the invention, when in deballasted condition, it will achieve a transit speed of about 20 knots, which is unique for a heavy lift vessel. Also with cargo the multihull vessel will have superior speed performance compared with designs of today. The multihull vessel according to the invention will further be able to lift/lower down heavier objects than what is possible today, and this operation will be carried out in a condition which the vessel has very good stability due to the multihull design and the special bottom construction.

This is achieved according to the invention with a multihull vessel of the type in which the hulls are united forward and where a combined bottom- and deck arrangement are binding together the area between the hulls from where they are united together and aftwards. The multihull vessel is identified in the way the combined bottom- and deck arrangement are linked together in the forward part of the vessel by a transversal axis arranged with a bearing in both mentioned hulls of which the bottom/deck arrangement can be lowered down at the vessel's aft part and be turned via the hinged construction towards the vessel's bottom area.

The invention shall be more clearly defined by means of a design sketch example of the vessel, with reference to the enclosed drawings, of which:

Fig. 1 shows the multihull vessel shown from the side,

Fig. 2 shows the multihull vessel shown from above.

Fig. 3 shows a midship section of the vessel in bigger scale seen from forward,

Fig. 4 shows a midship section of the vessel in bigger scale seen from aft.

With reference to the figures is the multihull vessel 1 shown consisting of a first hull 2 and a second hull 3. Between the hulls is shown a combined bottom-and deck structure 4 (hereinafter called bottom) which are covering the area between the two

hulls

2,3 from the unified mentioned hull and aftwards to the vessel's stern 5. The bottom 4 is in the forward part connected to the

hulls

2, 3 by a turnable hinged arrangement 6. The hinged arrangement 6 is supported in both

hulls

2, 3. The bottom 4 can in this way be turned down in to water below the vessel 1 around the mentioned transversal hinged arrangement 6. The bottom 4 can further be filled by ballast water and manoeuvred below the vessel 1 and forward 180 degrees, such that the area between both

hulls

2,3 will be opened and reachable for example for lifting operations. The bottom 4 is further arranged with two tunnel-propellers (thrusters) for manoeuvring of the bottom under water (in submerged condition).

In normal condition, i.e. bottom 4 in almost horizontal position and arranged as a deck construction between

hulls

2,3, the bottom 4 will be fastened/locked to the

hulls

2,3 by a hydraulic lock bolts 8 which are fixed mounted to the

hulls

2,3 engaging long the bottoms sides.

The vessel 1 is further outfitted with crane arrangements 10 which is mounted on both sides of the

hulls

2, 3. With reference to fig. 1,2 and 3 the vessel 1 is shown in operational service condition with closed bottom 4, in fig 4 the area between the

hulls

2, 3 aft of the joints is open, such that the bottom 4 points 180 degrees forward.

As the bottom 4 is ballasted and lowered down, the vessel 1 will achieve a very good stability and it will further be achieved a sheltered working area between the

hulls

2, 3 for possible lifting operations. At a lifting operation, the object which is lifted from sea bed will be brought in position between both

hulls

2, 3, where the bottom 4 then is located in 90-180 degree position downwards/forward, comp. fig. 4. When the objective is close to the sea surface, the bottom is turned (manoeuvred) 4 back to and below the object, such that the bottom 4 at deballasting increases the buoyancy and secures the objective when this is breaking the sea surface in which the gravity will increase considerably. Deballasting of the bottom 4 will be an important contribution in respect of the vessel's lifting capacity in this critical operational phase. After the bottom 4 is secured to the vessel's

hull

2, 3, the lifted object can be transported safely to the destination.

The vessel can as earlier mentioned be utilised to remove for example offshore-installations in the North Sea and other ocean areas. This operation can consist of preparation of removing of installations, cutting up of steel constructions for preparation for lifting, and lifting of installations into the vessel. Installations can be dismantled into parts, and the parts placed in the

catamaran hulls

2, 3, and/or the parts to be placed on the bottom 4 for direct transport to the depot. Heavy lifts will besides the force from the lifting crane 10, be executed by utilising the buoyancy force which is made free due to the bottom 4 has been deballasted. This is giving extra force in the last phase of the lift, which are crucial in respect of loss of buoyancy, in the moment when the objective are breaking the surface. Also the ballasting/deballasting of the

catamaran hulls

2, 3 as such will be used in parallel to increase the lifting capacity further.

An example of a service area for the vessel is positioning of modules/heavy equipment on the sea bed, together with removing same type of equipment.

In deballasted condition the vessel will according to the invention be able to achieve a speed which considerably exceeds the speed of crane vessels of to day. This means that the vessel can be transferred quickly to an emergency spot if so desired, and in this way have a great competing advantage compared with lifting vessels of today. Also in loaded condition the vessel will have a great speed advantage compared with competing vessels, because these competing vessels (mainly heavy lift crane vessels) are dependant of barges to transport the installations into positioned site.

Another area the vessel can be utilised for is assistance for, stand-by and rescue operations. The vessel will on these areas be superior in comparison to vessels in operation today due to the invention with better performance in respect of bollard pull and transit speed in comparison to existing vessels, which means that the emergency target can be reached quicker. Accommodation facilities and landing deck 11 for helicopters with twinrotors will make the present vessel especially well suited for extensive and complicated rescue operations.

With background in the inventioned vessel's lifting capacity down to 6.000 m depth, another interesting area for using the vessel will be rescuing of total lossed steel vessels and their cargo.

The vessel according to the invention will be classified with the highest ice class, which means that the vessel can be operated in arctic areas.

Claims

Multihull vessel (1) of the type in which the hulls (2,3) are united in forward part of the vessel and where a combined bottom- and deck structure (4) are mounted together and covering the deck area between the hulls (2, 3) from the place where united together and aftwards, characterized by the combined bottom-and deck structure (4) being hinged in the forward part of the vessel via a transverse hinged arrangement (6), whereby the bottom-and deck structure (4) can be lowered down at the vessel's aft end and be turned around the hinged arrangement (6) in an angle up to 180 degrees.
Multihull vessel (1) according claim 1,
characterised in that the bottom- and deck structure (4) along its side edges is provided with a sufficient number of fastening points for receiving hydraulic locking bolts (8) mounted in the respective hulls (2, 3), on which bottom and deck structure (4) at activating of the hydraulic locking bolts (8) is fastened to the hull (2,3).