Two recent projects have involved Strainstall in the design, manufacture and commissioning of force and strain measuring systems.
One project was an Integrated Marine Management System (IMMS) for the hull of the new Shenzi Tension Leg Platform, TLP, deployed in the Gulf of Mexico, by BHP Billiton. The EPC were MODEC Inc. Due to the occurrences and severity of hurricanes in the Gulf in recent years, the system needed to be robust and reliable, designed to withstand a 1000 year storm and have a 25-plus year life.
The system included:
- Tendon Compression Load Cells rated to 2500Kips (the largest ever supplied), to monitor tendon tensions installed in the tendon porches approx 120ft below the surface.
- MetOcean monitoring.
- Ballast control including tank levels.
- Load management.
- Fire and gas detection
- Motion and position monitoring.
- Ventilation and HVAC monitoring.
All of these components were integrated into a fully redundant PLC/HMI system.
The system provides the operators with a full range of hull parameters including the tensions and bending in the tendons, draft, motion and inclination, tank levels, position, fire and gas status, ventilation and HVAC, environmental and oceanographic parameters to allow them to safely carry out oil production.
Strainstall has also been awarded the contract to supply its Quick Release Hooks and Integrated BerthManager System for four new floating natural gas liquefaction units, (LNG Producers), with an option for a fifth, being constructed by Samsung Heavy Industries in Korea for FLEX LNG. These LNGPs will be the first dedicated offshore Liquefaction Units and will be used to develop stranded gas fields offshore. The LNGP is a self-propelled vessel that will be moored at the gas field and risers will bring natural gas aboard. The vessel is able to pre-treat and liquefy natural gas, store and offload LNG in an offshore location.
The requirement for these LNGPs to be deployed for up to 25 years in remote waters, with minimal allowance for any downtime or dry docking, meant that all the equipment supplied needed to be proven, rugged, reliable and easily maintainable.
The Strainstall scope of supply for each vessel is:
- GPS DockAlert vessel approach monitoring.
- Quick Release Hooks.
- Remote controlled hook release.
- MoorAlert mooring load monitoring.
- Local hook tension displays and alarms.
- Hook release panels in the control room and on vessel deck.
- BerthManager integrated monitoring, display and logging.
LNG Carriers will come alongside the LNGP, moor side-by-side, and carry out ship-to-ship cargo transfer. The LNGC will approach the LNGP using the GPS DockAlert to provide the pilot with information on relative speeds, relative headings, etc, of the two vessels. Once alongside the LNGC will moor to the LNGP using the Strainstall quick release hooks fitted with remote controlled hook release, and MoorAlert load measuring pins to provide real time monitoring of tensions in the mooring lines. Local displays provide mooring line tensions and include audible and visual alarms in the event of any over or underloads. Everything is integrated into the new Strainstall Offshore BerthManager Software, which then provides the LNGP control room personnel with full display, alarms and logging of all data.
Strainstall can also provide instrumentation for a wide variety of other offshore structures including buoys, fixed platforms/SARS/Semi-Subs and FPSO's, to monitor parameters including anchor load measurement, crane load monitoring, product pressure and flow, riser movement, hull structural monitoring and buoy to anchor distance.
Enter X at www.engineerlive.com/iog
Sandy Thomas, Marine Director with Strainstall UK Ltd, Cowes, Isle of Wight, UK. www.strainstall.com
