Consultations with operators and other key stakeholders identified the need for a new type of crane transfer device. They challenged Reflex Marine, UK, to develop a safe, efficient, low cost device, suitable for wide implementation. They also stressed the importance of a robust verification programme to confirm performance.
The safety of crane-based crew supply compares favourably with helicopter operations, with a relatively low level of fatalities, although injury levels have been comparatively high. Driven by a concern for safety, high litigation costs and risk to reputation, most major operators have now taken steps to try to reduce their exposure in this area, but were looking for further improvements.
Crane transfer risks
Transfer incident data collected from around the world gave Reflex Marine's design team a more precise understanding of what goes wrong during transfer operations. The primary risks during crane transfers are falls, heavy landings, side impacts (usually during pick up) and occasionally immersion.
Recently, industry "best practice" has improved, although implementation of higher standards is not yet as widespread as it could be. This can probably be explained by the following reasons:
• A lack of widespread understanding of the risks,
• A lack of understanding of the potential solutions,
• A strong attachment to traditional practices,
• A reluctance to invest for economic reasons often connected to the reasons above
Design Objectives & Process
It was agreed that the following design objectives had to be met:
Passenger protection: The protective features developed were based on analysis of a database of over 70 crane transfer incidents, which include seven fatalities.
High transfer rates: High transfer rates (passengers per hour) are achieved by ensuring passenger entry and egress can be achieved in less than five seconds, giving cost and safety benefits.
Logistical convenience: The capsule fits into a standard shipping container thanks to its small footprint, also making the unit easier to store offshore.
Critical load path: A minimal number of critical load path components reduce the likelihood of damage or degradation. FEA stress analysis was used to evaluate the key components.
Shock absorption system: A wide range of engineering elastomers and foams were evaluated in order to identify materials that provided excellent shock protection and a durable interface.
Stretcher facility: The capsule is designed to allow a stretcher casualty to be carried conveniently and in a protective environment.
Economy: A focus on high volume production, with associated capital investments in manufacturing plants, allows the capsule to be supplied at a very competitive price, making safe and efficient operations affordable to all.
Proof of design
The capsule was put through a rigorous verification programme to confirm its performance. Key elements of the evaluation were as follows: Stability testing, impact and load testing, immersion testing and design assessment.
A rigorous process of design, verification and testing has demonstrated that the new Toro capsule meets the key demands of operators providing a highly protective transfer environment, a high level of passenger acceptance, with an intuitive ride experience and a wide weather operating envelope. The Toro capsule also provides high transfer rates and an affordable transfer solution suitable for a wide range of industry applications.
Continued focus on risk and operator support will help to ensure that safe transfers are accessible to the whole offshore industry and not just a select few.
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