Large diameter mooring turret with compliant deck and frame
First Claim
1. In a vessel-turret assembly including a moonpool (5) in a vessel hull structure (43) and a turret rotatably supported within said moonpool by an axial bearing structure that includes vertical wheels (12) between an upper circular rail (26U) mounted on said turret and a lower circular rail (26B) mounted on said vessel hull structure (43), wherein said lower rail (26B) deflects due to vessel hull structure sagging in response to environmental forces, an improved turret (100) characterized by,a turret main deck (1) to which said upper circular rail is mounted,a chain table (3) separated vertically from said main deck (1) and arranged and designed for coupling with anchor legs which extend to the sea floor, anda connecting structure connected between said turret main deck (1) and said chain table (3),said turret arranged and designed to have a flexibility such that said upper circular rail (26U) substantially conforms in deflection with said lower circular rail (26B) when said vessel sags in response to vertical force acting on said turret.
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Accused Products
Abstract
A very large diameter turret for mooring a VLCC class FPSO vessel. A large diameter rail and wheel bearing system is disposed between a turret main deck and the hull of the vessel. The turret is designed for a flexibility to allow the turret main deck to conform to the sag or hog of the vessel so that excessive forces on the wheels of the bearing system are avoided. The turret'"'"'s main deck, in a preferred embodiment, includes a center hub, an outer ring, and spokes between the hub and outer ring. A lower chain deck is preferably connected to the main deck by pillars or columns, or alternatively by riser tubes alone, or other structures that achieve the desired flexibility of the main deck.
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Citations
35 Claims
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1. In a vessel-turret assembly including a moonpool (5) in a vessel hull structure (43) and a turret rotatably supported within said moonpool by an axial bearing structure that includes vertical wheels (12) between an upper circular rail (26U) mounted on said turret and a lower circular rail (26B) mounted on said vessel hull structure (43), wherein said lower rail (26B) deflects due to vessel hull structure sagging in response to environmental forces, an improved turret (100) characterized by,
a turret main deck (1) to which said upper circular rail is mounted, a chain table (3) separated vertically from said main deck (1) and arranged and designed for coupling with anchor legs which extend to the sea floor, and a connecting structure connected between said turret main deck (1) and said chain table (3), said turret arranged and designed to have a flexibility such that said upper circular rail (26U) substantially conforms in deflection with said lower circular rail (26B) when said vessel sags in response to vertical force acting on said turret.
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31. A turret for mooring a vessel comprising,
a turret main deck (1), an axial bearing structure (26U) mounted on said main deck, a structure connected to said turret main deck, where said structure is arranged and designed for coupling of anchor legs and risers, said turret main deck characterized by flexibility parameters δ - /D1 and A1/D1,
where A1 represents a thickness of said turret main deck, D1 represents a diameter of said axial bearing structure mounted on said main deck, δ
represents a predetermined maximum deflection of said axial bearing structure, andsaid parameters δ
/D1 and A1/D1 fall within a region A defined on a graphical plot of δ
/D1 versus A1/D1 where A1/D1 values are between 0.05 and 0.150, and δ
/D1 are below lines connecting points A1/D1=0.05, δ
/D1=0.001 and A1/D1=0.100, δ
/D1=0.0005; and
A1/D1=0.100, δ
/D1=0.0005 and A1/D1=0.150, δ
/D1=0.00035.
- /D1 and A1/D1,
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32. A turret vessel arrangement comprising
a vessel having a moonpool with a vessel bearing surface, a turret disposed in said moonpool and having a flexible main deck with a main deck bearing surface, bearing members placed between said vessel bearing surface and said main deck bearing surface, a flexible structure connected to said flexible main deck, where said structure is arranged and designed to couple anchor legs and at least 40 risers, said main deck and said structure being cooperatively arranged and designed such that said main deck bearing surface flexes due to vertical forces acting on said main deck from said anchor legs and said risers, so that said main deck bearing surface conforms with a sagging shape of said vessel bearing surface when said vessel sags in response to sea forces.
Specification