When a vessel is severely damaged, there may come a time when it has to be abandoned. For such a situation, vessels are required to have adequate lifeboats (or liferafts) on board for all personnel. In such an emergency, the evacuation of divers in saturation represents a particular problem as they cannot be readily decompressed in order to be evacuated in the same way as other crew members. The divers need to be transferred to a pressurised compartment which can be detached from the diving system on the vessel and launched or floated into the sea. This means that, for all saturation diving operations, a hyperbaric rescue unit needs to be provided that, in the event of a vessel evacuation, is capable of evacuating the maximum number of divers. Planning and facilities also need to be in place to ensure that the hyperbaric rescue unit and its occupants are taken to a designated location where they can be decompressed back to surface pressure in a safe and controlled manner.
JFD was formed by the amalgamation of four companies – the National Hyperbaric Centre, Divex, JFD and DCE. It employs around 400 people involved in all aspects of design, manufacture, maintenance and operation of subsea equipment, and one of its objectives is to establish a global hyperbaric rescue service that makes saturation diving safer and saves the industry money. The company has been involved in submarine rescue for 31 years and currently provides submarine rescue services for five nations from three main service centres – Naval Base Clyde (Faslane UK), Singapore and Australia (Dampier). Divex is well known as a leader in the design and build of hyperbaric rescue facilities (HRFs), and the National Hyperbaric Centre is renowned as a hyperbaric reception facility.
Speaking at the 2015 Diving Seminar, Brian G Redden, director, global hyperbaric rescue services at JFD, described the current status of hyperbaric rescue in the commercial diving industry. He noted that the majority of saturation diving around the world now incorporates use of a self-propelled hyperbaric lifeboat (SPHL) or hyperbaric rescue centre (HRC). IMCA DO52 and DO53 guidance and OGP Report 478 lay out the requirements for hyperbaric rescue, but interpretations vary by region with solutions made up of a mixture of SPHLs and HRCs with life support packages. Then there are Statoil’s rapid response rescue vessels and fixed and mobile HRFs but no consistent approach.
“Arguably, the main hyperbaric rescue issue worldwide is the lack of credible, safe and timely SPHL recovery methods,” Mr Redden said. “One option for SPHL recovery is based on a service model developed and used over three decades of submarine rescue operations.”
In the JFD service model, JFD Submarine Rescue, customers contract for capability. JFD provides a complete rescue service with guaranteed response time for a monthly fee. JFD is responsible for equipment provision, personnel, assurance, technical support, maintenance and training. The company uses a davit-based launch and recovery system (LARS) which was designed by JFD and Caley and proven in Canadian Coast Guard trials in up to sea state 6. This is, the company believes, more manageable than a stern A-frame with easier lee with side recovery, two-point lift, adjustable cradles for one or two up to 24-person SPHLs and offload directly to an HRF.
A vessel of opportunity is deployed that is pre-nominated and pre-engineered for the davit LARS. Such a vessel needs 16m x 12m free deck space within 1m of the bulwark. Its operation is co-ordinated with International Oil and Gas Producers (IOGP) members for rapid response. A minimum of one vessel of opportunity must be within four hours’ sailing of all of the three base locations at any one time. The position of the vessel is monitored via AIS. The UK Continental Shelf (UKCS) is covered with four davit LARS operating from three bases with a fourth spare system. It is operational in up to sea state 6, available all year and is fully compliant with OGP Report 478 requirements. JFD is required to guarantee 32 hours to first rescue.
“JFD’s objective is to save the industry money and make diving safer,” Mr Redden said. “In the context of SPHL recovery, the JFD approach saves money by removing the need for a dedicated vessel compared to other options.” The ships really are the expensive bit, he says. “JFD’s davit LARS SPHL recovery method is currently the safest one around,” he said. “Alternatives such as stern ramp/stinger recovery risks damaging mating flange, and stern A-frame single-point lift risks swinging collision damage in anything but flat calm conditions.
“A global hyperbaric rescue service is achievable but only with cross-industry co-operation,” he concluded. “Submarine rescue is a parallel world with lots of synergies. Let’s capitalise on the lessons learned there.”
Bailout rebreather enhances safety levels
Recent weeks saw JFD unveil a new compact bailout rebreathing apparatus (COBRA) for commercial divers, which it says is “a direct response to the urgent need for significant improvements in safety in the saturation diving industry”. The system significantly extends the duration of the supply of emergency breathing gas, delivering 45 minutes of emergency life support at a depth of 120m. A conventional open-circuit 300 bar twinset bailout system will deliver only seven minutes at that depth. The extended emergency breathing gas supply significantly improves the likelihood of a successful rescue in the event of an emergency.
COBRA was designed and developed by JFD as part of its Divex range of rebreathers and supplies up to 45 minutes of fully independent breathing gas in an emergency scenario. The system is designed to be smaller than most bailout systems, ensuring COBRA does not impact on the operations of the diver. It is entirely mechanical with no complex electronic systems that could potentially compromise safety. It is operated via a single turn activation and can be tested prior to its use without affecting the functionality of the system, providing reassurance to the diver that there is a reliable and efficient life support system in place in case of an emergency. “Compared to conventional bailout methods, which at certain depths provide less than 10 minutes of breathing gas, COBRA is a significant step forward in improving subsea safety,” JFD claimed.
Giovanni Corbetta, managing director at JFD, said, “Modern diving operations bring significantly more risk, and continuing to use systems that can only provide a few minutes of emergency gas puts lives in danger. The COBRA system has been rigorously tested and has a proven ability to significantly extend the provision of emergency life support without impacting the operations of divers, allowing them to carry out their duties with minimal risk.”
It is widely recognised in the commercial diving industry that the same extended bailout breathing facility used as standard in operations at depths of over 200m of sea water should be available for divers operating at 50–200m, a far more common operating depth. Modern diving operations often require the use of extended excursion umbilicals from bigger diving bells, meaning that the time required to return to the safety of the bell can be greatly extended.
When combined with factors such as cold water, darkness, subsea structures and a diver’s alarm and disorientation, the risk to the diver’s life is significantly increased. It is critical that divers have a substantial emergency breathing gas supply that is adequate for the operating conditions to ensure that their safety is assured. The diving industry has already begun to recognise and address the increased risk associated with modern saturation diving operations. The Norwegian petroleum industry has dictated via NORSOK standards that divers must have a minimum of 10 minutes of emergency breathing air, circulated at a rate of 62.5 l/min. This requirement renders many common systems such as scuba out of scope and therefore unsafe for use.