Khalifa Point CALM buoy load monitoring system.

James Fisher Strainstall has designed, tested and commissioned a CALM buoy load monitoring system for Khalifa Point in Pakistan.

James Fisher Strainstall's (JF Strainstall) force, strain and load measuring systems are used in the oil and gas industry, both on and off-shore. These systems range from specialist load cellsto custom designed, fully integrated, multi-sensor packages that monitor vesseldraft and ballast, metocean conditions, vessel loading and structural dynamics.

The Khalifa buoy has been refurbished having been previously deployed in the Middle East. In compliance with Bureau Veritas rules, a hawser load monitoring system, together with a navigation aids and control/communication package, was required.

The system uses load pins incorporated into the mooring bridle to provide a continuous real-time monitoring of loads in the hawser. It is designed to protect the mooring equipment by ensuring it is not overloaded and in danger of breaking the hawsers and risking the tanker drifting. This is particularly vital during product transfer operations due to the increased risk of  spillage.

The scope of supply for the buoy included a JF Strainstall dual bridge load measuring pin (with a design life of 25 years plus), Intrinsically Safe line amplifiers to condition the signals from the load pin, and a PLC-based data logging system. Communication of this data to the ship is via a wireless connection which includes the AIS and provides the additional benefit of buoy location and identification to local shipping. Remote control and back-up data monitoring is available using a GSM communication module through SMS messaging.

In addition to the AIS Transponder the navigation aids package is completed by a 5nm LED navigation light and a ½ mile fog horn which can be controlled from the display or by SMS text message from authorised mobile phone.

The primary channel for receiving  buoy data at the offloading tanker is through the vessel’s Class A AIS transponder (via the pilot port), to a receiving module that retransmits the data to any web enabled display. In this case a Netbook computer was supplied, however, any browser based device with WiFi can be used. Should there be a problem with the vessels pilot port, an AIS receiver is also supplied as part of the carry on equipment that is housed in a compact backpack.

In addition to hawser load, the battery voltage, fog horn and navigation light status are also displayed to provide the mooring master with real time information, and there is also alarm notifications in the event of any predefined parameters being exceeded.

The equipment supplied for the buoy has been designed to withstand use in harsh marine environments and is certified for use in Zone II Hazardous Areas. The system is powered by a solar charged battery pack for long-term, maintenance free operations and screens are available to the operators showing current operational status and all alarm conditions.