CALM Buoy

					CALM Buoy
for BHP Billiton Angostura Field Offloading Terminal




                                                 Power by People
BHP Billiton Angostura Field Offloading terminal                                        Key elements: Buoy Arrangement
                                                                                        The Bluewater turret buoy consists of a steel turret sus-
Project Overview                                                                        pended from a bearing. This is attached to the buoy
                                                                                        body and connected at the lower end to the anchor legs
Bluewater Energy Services B.V. have completed design and fabrication of a Catenary      with ratchet-type chainstoppers, located in the spider
Anchor Leg Mooring (CALM) buoy and pipelines for the Angostura field in Trinidad        structure.
and Tobago.
                                                                                        Arrangement Details:
The CALM buoy is scheduled for installation in 3rd Quarter 2004. It will be moored
                                                                                        • The buoy body will be allowed to weathervane
about 4 km off the coast in a water depth of 26 m. This new facility will facilitate
                                                                                          freely through 360° around the turret
tanker berths, servicing the loading of tankers up to 150,000 dwt.
                                                                                        • Six anchor legs, in a 3 x 2 confiriguration holds its mooring position
                                                                                        • Two chain hawse pipes will extend from the bottom plating of the buoy
Buoy concept and design                                                                   body to the deck
                                                                                        • During offshore installation, the pipes will be aligned with the spider’s
The CALM buoy concept was chosen as a more cost-effective and faster solution.            chainstopper assemblies
Bluewater’s turret buoy design offers increased loading and offloading efficiency for   • The deckhouse wall will form an extension of the hawse pipes, up to
tankers; maximum throughput can be achieved safely, while maintenance and down-           the deckhouse roof level
time are significantly reduced.                                                         • An air winch will be fitted in the deckhouse. During installation, the
                                                                                          winch can be rigged to pull in the anchor legs through the hawse pipes
The concept incorporates:                                                               • Open windows in the hawse pipes, at deck level, will allow the chains to
                                                                                          be checked and cut after being locked in the chainstoppers
• A square turret CALM buoy                                                             • Two riser pull-in pipes will extend from the turret bottom plating to the
• A Pipeline End Manifold (PLEM)                                                          turret deck level, to allow connection of the submarine hoses to the
• Submarine and floating hoses                                                            turret piping, using the winch
• Single 30-inch onshore/offshore pipeline                                              • The 3 x 2 anchor leg pattern provides a chain free sector for the
                                                                                          submarine - specifically designed to withstand extreme storm conditions
Pipeline, PLEM and hoses                                                                • The two submarine hose strings will be
                                                                                          maintained in “Chinese Lantern” configuration,
                                                                                          with flotation collars. It will be connected to the
From the manifold in the tank area of the BHPB Terminal, one 30-inch pipeline will
                                                                                          16-inch turret piping by means of a swivel joint
run to the shoreline and will terminate at the PLEM.

Special features will include:                                                          Product Swivel and buoy Body
• Piggable pipeline and PLEM                                                            This configuration will allow stabilised oil to flow through
• PLEM with sliding provision to ease                                                   the submarine hose to the dual 16-inch product piping in
  hookup to pipeline.                                                                   the turret. It will then be transferred to the rotating buoy
• Direct oil export from the CALM buoy to                                               body by means of single 16-inch piping, via a pipe-type
  the tanker via a floating hose                                                        single product swivel. An overboard pipe spool will con-
• Flexible design, to accommodate a future                                              nect the buoy body piping to the floating hose string.
• pipeline extension                                                                    Within the product swivel, a sealing system will prevent leakage; a leak detection
                                                                                        system will provide continuous monitoring of the pressure between the
                                                                                        seals – providing an important safety feature.

                                                                                        The buoy body will be connected to the turret via a three-race roller bearing and
                                                                                        fitted with a closed deckhouse. The design solution protects critical equipment
including the bearing, valves, electrical                                               The integrity of the two floating hose string has been carefully considered. When
equipment, grease pump unit and product                                                 operational, the strings will be equipped with appropriate lighting and breakaway
swivel. It also reduces maintenance                                                     couplings, to avoid spillage in the event of uncontrolled tanker disconnection.
requirements. Such work can be under-
taken safely inside the deckhouse.                                                      Additional Equipment
The interior of the buoy body will consist
of watertight compartments, each of which                                               The CALM buoy system will also include:
can be checked or sounded for water                                                     • A bilge pump
ingress. Draught marks on the hull exteri-                                              • A rotation stopper system
or will also allow the floating condition of                                            • Rigging equipment
the buoy to be monitored.                                                               • Ballast and trim facilities
                                                                                        • Sacrificial anodes
Access to the buoy:                                                                     • Lifting and towing padeyes
                                                                                        • Pick-up arrangements for the floating hose and mooring hawser
• A boat landing platform and a ladder will
  provide access to the main deck
• Overboard work platforms will be                                                      Paint
  provided, to assist with hose and mooring hawser handling
• The hull will be fitted with fendering                                                On the Angostura CALM, a new type of Polyester Glassflake paint system was applied
                                                                                        to the underwater, hull, deck and deckhouse external areas and does have the fol-
                                                                                        lowing advantages:
Tanker Interface and Mooring Arrangement                                                • High impact and abrasive resistant system.
                                                                                        • Excellent anti-corrosive properties.
The tanker will be moored to the buoy by a dual hawser arrangement, shackled to a
                                                                                        • Marine life will have no or little effect on the coating performance.
mooring uni-joint on the buoy deck. The uni-joint is integrated with the buoy via
                                                                                        • It is environmental friendly since no anti-fouling is needed.
mooring lugs, fitted with bushes to prevent excessive wear. At the tanker end of the
                                                                                        • Based on the above service lifetimes up to 30 years without an overhaul are
hawsers, chafe chains will be provided to prevent damage from the tanker fairlead.
                                                                                          achievable
Hawsers guides and hardwood protection on the buoy deck will minimise the risk of
damage. A load monitoring system will be installed in the mooring uni-joint, inter-
faced to provide audible and visual alarms to prevent hawser overloading. Batteries     Special systems
in the deckhouse and solar panels on the deckhouse roof will provide the buoy’s
electrical power. Electrical power will be provided for the telemetry system, naviga-   The Angostura CALM Buoy is provided with a Telemetry system will include:
tion aids and instrumentation.                                                          • Tanker portable unit
                                                                                        • CALM Buoy unit
                                                                                        • PALM top
Safety                                                                                  • Load pin and associated equipment for load monitoring
                                                                                        • Navigational light and radar reflector
Appropriate safety systems and alarms have been incorporated into the buoy’s
                                                                                        • Real time load monitoring, storage of the mooring load data in the CALM Buoy
design. Deck and overboard platform will be provided, with railing and grating.
                                                                                          unit and the software to provide cumulative fatigue damage information
Navigation Aids include:
                                                                                        The following signals are transmitted from the CALM Buoy unit and to the Tanker
• A marine flashing lanterns                                                            Portable Unit:
• A radar reflector                                                                     • Battery voltage
                                                                                        • Solar panel charging current
In addition to providing normal marine signals, the foghorn will provide an audible     • Status of the communication link
alarm for the mooring hawser load monitoring system. An additional flashing bea-        • Real time load monitoring and automatic warnings for high loads and
con will also provide a visual alarm for hawser loads. Hand-operated safety items         disconnecting criteria
will include fire extinguisher and personal life-saving equipment.
BHP Billiton Angostura Field Offloading Terminal
On completion of the CALM Buoy system for the BHP Billiton Angostura Field, Trinidad and Tobago will have an offshore terminal ranking
among the best in the world




    Buoy Dimensions                                                              Location
       Buoy body (including skirt)                             13.5 x 13.5 m       4 km offshore Trinidad and Tobago
       Buoy body (excluding skirt)                             10.25 x 10.25 m     Water depth                                26 m
       Hull height                                             4.1 m
       Projection of spider below hull                         1.8 m
       Total height (including fog horn)                       11 m
                                                                                 Design Criteria
       Weight                                                  200 MT              Design life                                25 years
       Centre of gravity above keel                            1.8 m
       Installed draft                                         4.5 m             Mooring Equipment
                                                                                   Hawser length                              50 m
    Certification                                                                  No. of hawsers                             1
       The system has been designed and built as an OI 100 AT Single Point         Circumference                              13”
       Mooring and Loading Terminal with Lloyd’s Register of Shipping.             Hawser type                                single
                                                                                   OCIMF Chafe Chain                          Type B
    Anchor System
       Anchor legs                                             6                 Buoy Piping System
       Pattern                                                 3x2                 Design pressure                            19 bar
       Length                                                  325 m               Turret piping                              2 x 16”
       Chain size (studless links)                             76 mm               Turret product valves                      2 x 16”
       Anchor points                                           6 AHT anchers       Swivel                                     1 x 16”
       Pretension angle                                        45°                 Buoy body piping                           1 x 16”
                                                                                   Buoy body product valves                   1 x 16”
    Submarine Hose System
       Strings                                                 2                 Floating Hose System
       Size                                                    16”                 Strings                                    1
       Hose length                                             35 ft or 40 ft      Size                                       20” / 12”
       No. of hoses                                            3                   Hose length                                30 ft or 35 ft
       Pressure rating                                         19 bar              Pressure rating                            19 bar




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