Material or article handling – Marine loading or unloading system – Marine vessel to marine vessel
Patent
1994-09-12
1996-11-26
Merritt, Karen B.
Material or article handling
Marine loading or unloading system
Marine vessel to marine vessel
4141396, 4141382, 4141384, 4141397, 212308, 254900, B63B 2716
Patent
active
055778747
DESCRIPTION:
BRIEF SUMMARY
The invention relates to a method for transfer of loads from a vessel that moves with heavy seas to a stationary or mobile installation, by the use of at least one lifting cable or wire and at least one hoisting means, where the load in its starting position stands on a rack on the vessel.
The invention also relates to an apparatus for transferring a load movable in a substantially vertical direction to a temporarily stationary suspending means such as a cable or string at an instant when the load has no significant kinetic energy.
The invention relates also to a method for constructing an oil platform on a Jacket or support structure positioned on the sea bed, preferably with the aid of the method and apparatus mentioned above.
In connection with Norwegian patent no. 159 186 and with patent application NO 894 762, further developmental work has been carried out with the objective of devising a method for direct installation of modules from a ship to a platform in accordance with the construction method previously described in the above cited patent publication. There has also been developed a type of platform consisting of a system of easily mountable and dismountable modules, deck and equipment which may easily be mounted directly from barges or a supply ship on the field without using floating cranes.
The methods currently in use today for offshore load transfer, by lifting loads from a ship to fixed or mobile installations, involve subjecting the lifting gear as well as the loads to some very significant dynamic stresses in that the loads are transferred whilst they are in motion, and consequently have high kinetic energy.
In the transfer of smaller loads, for example service goods and support equipment for production platforms and drilling rigs, the dynamic forces are absorbed by existing cranes and lifting gear with the aid of hydraulic cylinders and hydraulic accumulators, so-called heave compensators. Also, the cranes currently used on board oil platforms are limited to weights of 15-80 tons.
In lifting of heavier equipment, such as modules, foundation frames, manifold stations, etc., having weights from 100 to 7000 tons, the dynamic forces will be so considerable that lifting with cranes placed on the platforms is not practically feasible. Such weights are currently only lifted with floating cranes of various types. Most of these cranes are also equipped with hydraulic compensator systems to dampen the effect of the dynamic loads.
A major disadvantage with the use of contemporary lifting equipment is it physical size and the fact that the lifting and load handling must take place over other equipment. This entails particular limitations with respect to access, for example, in installation of equipment or modules situated under the platform.
Furthermore, the lifting of heavier units over the vital parts of the platform, such as processing plants, etc., means that processing must be stopped for security reasons during the period in which lifting takes place. The financial consequences of this can be very considerable.
In addition, the huge floating cranes must be mobilized and anchored at the platform. This involves special complications when the sea bed around the platforms is overlaid with pipeline systems, manifolds, etc., which can be damaged by anchors and chains. Furthermore, the crane vessel will normally require the assistance of 2-4 tugboats or supply ships for the anchoring, etc. Barges are needed to bring out modules and heavier equipment--usually one standard barge with a 10,000 ton displacement, pulled by two tugboats or supply ships.
The mobilization time and mobilization costs, in addition to operating costs for this equipment, are quite significant, even though the lifting operation itself takes only a short time.
Therefore, current methods establish clear limitations, both technically and financially, for direct lifting operations onto platforms or drilling rigs.
The limitations mentioned above are overcome by the present invention, which permits load transfer directly from a ship o
REFERENCES:
patent: 3329808 (1967-07-01), Fisher
patent: 4118012 (1978-10-01), Kerr et al.
patent: 4174188 (1979-11-01), Brun
patent: 4179233 (1979-12-01), Bromell et al.
patent: 4180362 (1979-12-01), Stair
patent: 4277053 (1981-07-01), Simon
patent: 4448396 (1984-05-01), Delago
patent: 4544137 (1985-10-01), Johnson
patent: 4629365 (1986-12-01), Kuriiwa
patent: 4666357 (1987-05-01), Babbi
patent: 4838522 (1989-06-01), Calkins
patent: 4919393 (1990-04-01), Calkins
Hess Douglas
Merritt Karen B.
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