- Verification of the mooring system: Anchors, Chain stoppers, Fairleads, Chains accessories, Tension measuring equipment, Anchor piles, Chains tensioning equipment
- Design of anchor points
- Evaluation (technical & commercial) and Support during procurement stage
- Mooring system installation method development (Buoy towing, mooring, hook up, submarine hose installation, umbilical installation, chain tensioning, bolt tightening, drag anchor or other type of anchoring system, hose configuration, pressure testing)
- Static & Dynamic installation analysis (utilizing standard analytical softwares e.g. OrcaFlex, MIMOSA, SIMO) to determine operational and weather criteria, including installation loads, tension requirement, stress/strain limits, etc.
- Installation vessel & equipment selection – feasibility, capacity and availability
- Installation procedure development depending on field layout / constraints
- Interface with specialist subcontractors and vendors
- Field engineering & operation support
- Survey support
- Cost benefits study and estimation, schedule
.. more on mooring and floating system..
Mooring system ensures that the floating platform is anchored to the seabed throughout its design life having to endure the environmental conditions. Moorings are used for Catenary Anchor Leg Mooring (CALM) Buoy for floating wind farms, nearshore terminal, FSO, FPU, FPSO, semi-submersible, spar up to the latest FLNG. Moorings are also used for the floating fish farms and feeding barges.
Mooring system consists mainly of:
- Drag anchors
- Suction piles
- Driven anchor piles
- Mooring and connecting shackles, kenter links, H-links (*ROV type shackles or special connectors can be designed to offer diverless connection)
- Mooring chains (studded or studless links)
- Spiral Strand Wire (SSW)
- High Modulus Polyethylene (HMPE) rope
The components of this mooring system are normally manufactured in different parts of the world and will be transported to the project site location either directly for installation or to marshalling yard.
The most cost effective method of installing mooring system which consists of drag anchors and mooring lines are done using Anchor Handling Tugs (AHT). However for large heavy piles, vessel with A-Frame or subsea crane will be required for the deployment operations. Once the pile is within installation tolerance, it is then landed on seabed until it achieves self penetration depth.
- For suction pile installation, ROV will close the vent hatch and utilize suction pump drive the pile into seabed.
- For anchor driven pile installation, Pile Guide Frame (PGF) will be required to assist positioning of pile. Then underwater hydraulic hammer will be used to drive the pile.
Mooring chains are usually shipped in bundles on Heavy Lift Vessel which will then be flaked in the marshalling yard, onto cargo barge or transferred directly to the installation vessel’s chain lockers. The chains can be deployed using the “chain curtain” method or spooled out via gypsy winch.
For deepwater projects, spiral strand wires or HMPE ropes are normally connected to the mooring chains as part of the system. Reel hub drives will be used to spool out the lines, with custom made Mooring Line Deployment Winch (MLDW) to deploy these lines.
For Tension Leg Platform (TLP), anchor piles are installed on seabed and then tendon joints are made up into vertical strings throughout the water column. The first end of the tendon string will have special connector that will dock and secure the string to the pile. The 2nd end will be terminated with Tendon Buoyancy Module (TBM) on the water surface in preparation for the TLP arrival and docking.
Therefore dedicated planning and novel methods can be developed to install the different types of mooring system. The methods chosen can decide the “make” or “break” of the project saving critical vessel time and the number of spread used.