OA11332A

OA11332A - Mobile offshore base.

Info

Publication number: OA11332A
Application number: OA1200000067A
Authority: OA
Inventors: Stafford J Menard; Trevor Robert James Mills
Original assignee: Mcdermott Technology Inc
Priority date: 1997-09-08
Filing date: 2000-03-07
Publication date: 2003-12-10
Also published as: CN1269759A; AU726878B2; EP1012036B1; TR200000642T2; BR9811761A; ID24329A; PT1012036E; AU8571898A; DK1012036T3; NO20001082L; NO322543B1; EP1012036A1; CN1107613C; EP1012036A4; NO20001082D0; DE69826692D1; ES2227866T3; DE69826692T2; WO1999012806A1

Abstract

A mobile offshore base (10) is formed from several individual single base units (12) that are connected together at sea to form the complete base. The complete base (10) forms a runway and support base for fixed wing and rotary wing aircraft and also provides space for stowage and transport of equipment and personnel. The single base units (12) are similar semi-submersible units that are linked together by hinges and/or U-joints to form the complete mobile offshore base (10). Each single base unit (12) is self-propelled and is also capable of independent operations at widely separated locations. The single base units are each formed from lower hulls, columns that extend upward from the lower hulls, and an upper hull attached to the columns.

Description

011332

MOBILE OFFSHORE BASE

BACKGROUND OF THE INVENTION 5 1. Field of the Invention

The invention is generally related to a military logistics base and more particularly to a mobile base offshore. 2. General Background

In military operations, in peace or war time, the 10 maintenance and/or replacement of matériel and personnel requires a base of operations. Due to political situations, as well aslimitations on availability of land, it has become increasinglydifficult to maintain a military presence in areas of the worldfar from the home country. Also, maintaining a military base in 15 several different countries is prohibitively expensive when such bases may not ail be needed on a full time basis. This leavesa need for some type of alternative base.

SUMMARY OF THE INVENTION

The invention addresses the above need. What is provided 20 is a mobile offshore base. The mobile offshore base is formed from several individual single base units that are connectedtogether at sea to form the complété base. The complété baseforms a runway and support base for fixed wing and rotary wingaircraft and also provides space for stowage and transport of 25 eguipment and personnel. The single base units are similar semi- . submersible units that are linked together by hinges and/or U- joints to form the complété mobile offshore base. Each singlebase unit is self-propelled and is also capable of independentoperations at widely separated locations. The single base units 011332 are each formed from lower hulls, columns that extend upward fromthe lower hulls, and an upper hull attached to the columns. BRIEF DESCRIPTION OF THE DRAWINGSFor a further understanding of the nature and objects of the5 présent invention reference should be made to the following description, taken in conjunction with the accompanying drawingsin which like parts are given like reference numerals, andwherein:

Fig. 1 is a perspective view of a single base unit of the10 invention.

Fig. 2 is a typical transverse section of a single base unitof the inventon.

Fig. 3 is a partial cutaway view of a single base unit ofthe invention. 15 Fig. 4 is a perspective view illustrating the single base units of the invention linked together to form a mobile base.DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTReferring to the drawings, it is seen in Fig. 4 that theinvention is generally indicated by the numéral 10. Mobile 20 offshore base 10 is formed from a number of single base units 12 that are connected together at sea. Each single base unit 12 isgenerally comprised of at least two buoyant lower hulls 14,columns 15, and upper hull 18.

As seen in Fig. 1 and 2, lower hulls 14 are preferably ship 25 shaped (streamlined with symetrically faired bow and stem shapes) to allow for movement at transit and operating speeds atthe efficient power and propulsion capabilities. Propulsion and 011332 3- dynamic positioning thrusters are indicated by numéral 20. A plurality of colurons 16 rigidly attached to and spacedalong the length of the lower hulls 14 extend upwardly therefrom.Columns 16 are illustrated as being square or rectangular in5 section but may be of any suitable shape.

Upper hull 18 is rigidly attached to the upper end ofcolumns 16 adjacent outer opposing sides of upper hull 18 suchthat lower hulls are spaced across the width of the upper hulland are parallel to the longitudinal axis of the upper hull.10 Bracing 22 rigidly attached between columns 16 and upper hull 18 provides support to minimize f lexing and maintain spacing betweenthe lower hulls 14. Upper hull 18 is sized and constructed toform an upper deck 24 and, in the configuration illustrated,three lower decks 26. Upper deck 24 serves as an aircraft runway15 and landing area for fixed and rotary wing aircraft as well an apron for loading and unloading the aircraft. Lower decks 2 6 areused for living space and storage space for equipraent andsupplies. Fig. 3 illustrâtes loading and storage capabilities.Each single base unit 12 is providéd with variable ballast20 tanks 28 in lower hulls 14 and columns 16. Variable ballast tanks 28 provide for operation as a semi-submersible vessel toselectively allow operation at different drafts. At transitdraft, the hulls 14 are at their shallowest draft and allow fortop speed. At operational draft, illustrated in Fig. 4, lower25 hulls 14 are fully submerged below the water surface to provide, relative to transit draft, a smaller water plane area through hull that greatly reduces pitch, roll, and heave in response to -4- 011332 wave action. Survival draft is selected during storms. Variableballast tanks 28 are operated to receive or expell water ballastin a manner well known in the art.

In operation, each single base unit 12 may be used5 individually or one or' more may be connected together as illustrated in Fig. 4 to form a mobile offshore base suitable forreceiving fixed and rotary wing aircraft. In this configuration,the connected units are preferably ballasted to an operationaldraft as illustrated to minimize motions from waves. For the10 purposes of forming a mobile offshore base using five individual units 12, as well as having usable individual units, eachindividual unit 12 is designed to be three hundred meters inlength, one hundred fifty-two meters in breath at the flightdeck, and seventy-five point six meters tall. For these15 dimensions, each lower hull 14 is two hundred seventy meters long, thirty-eight meters wide, and sixteen meters tall, withsymetrically faired bow and stern shapes. Depending upon thepayload, the transit draft is expected to be between thirteen andfourteen meters. The operational draft is expected to be thirty-20 eight meters and the survival draft is expected to be thirty-five meters. Spécial marine connectors 30, seen in Fig. 1, are usedto connect the units by means of hinges and/or U-joints. Spécialconnectors are required due to the large loads encountered. Suchspécial connectors are the subject of copending application25 Serial Number 08/XXX,XXX filed July 31, 1997.

Because many varying and differing embodiments may be made within the scope of the inventive concept herein taught and -5- 011352 because many modifications may be made in the embodiment hereindetailed in accordance with the descriptive reguirement of thelaw, it is to be understood that the details herein are to beinterpreted as illustrative and not in a limiting sense.

Claims

“6 = 011332 What is claimed as invention is:

1. A floating mobile offshore base, comprising a 'plurality ofsingle base units connected together, each of said single baseunits comprising: 5 a. at least two buoyant lower hulls; b. a plurality of columns- spaced along the length ofsaid lower hulls and extending upward therefrom; and c. an upper hull attached to the upper end of saidcolumns such that said lower buoyant hulls are spaced 10 across the width of said upper hull and each of said lower hulls extends substantially parallel to the longitudinalaxis of said upper hull.
2. The mobile offshore base of claim 1, wherein said single baseunits are connected together to form an aircraft runway and 15 apron.
3. The mobile offshore base of claim 1, wherein the draft ofeach of said single base units is selectively adjustable.
4. The mobile offshore base of claim 1, wherein said single baseunits are connected together end to end.. 2 0 5. The mobile offshore base of claim 1, wherein said single base units are self-propelled.
6. A floating mobile offshore base, comprising a plurality ofself-propelled single base units connected together to form anaircraft runway and apron, each of said single base unitscomprising: a. at least two buoyant lower hulls; b. a plurality of columns spaced along the length of 25 Γ» Ί Λ -7 -7 υι ι οό2 -7- said lower hulls and extending upward therefrom; and. c. an upper hull attached to the upper end of said columns such that said lower buoyant hulls are spaced « across the width of said upper hull and each of'said lower 5. hulls extends substantially parallel to the longitudinal axis of said upper hull.
7. The mobile offshore base of claim 6, wherein the draft ofeach of said single base units is selectively adjustable.
8. The mobile offshore base of claim 6, wherein said single base 10 units are connected together end to end. I