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New Trends in Subsea ROV Operations
We spoke to James Smith, Senior Structural Engineer about new trends in subsea ROV operations that might impact on vessel and operational choices.
In terms of regulation, NORSOK U-102 Standard has become more relevant for many operators in recent years. The requirements of this standard have presented engineering challenges for the certification of existing older systems. New ROV systems are also becoming increasingly sophisticated. Innovations include semi-permanent or residential variants which ‘live’ subsea for longer durations and recover to subsea garages. The cost reduction and safety benefits of such systems may seem obvious, but significant engineering and design analysis is required to demonstrate their feasibility. Their long-term reliability is key to making them a viable option. Such systems represent strong opportunities for onshore control, meaning delivering subsea workscopes without sending a ship to site at all becomes a possibility. Residential ROVs are often fully electric rather than electric-hydraulic which also supports a drive towards cleaner energy.
As well as being greener and more autonomous, ROVs are heading into deeper (>4,000m) waters. This adds numerous technical challenges to their operation such as working under higher pressures, larger power requirements and increased overall size and weight (including umbilicals). With deeper water, spooling of umbilicals becomes more important too. With umbilicals costing in excess of half a million dollars, these cannot realistically be considered consumable items and their integrity must be protected.
With everything becoming larger and more complex, it is worth considering the impact on support vessels. If you are lucky enough to be considering a new one, it is likely you have the chance to specify a built-in LARS system or moonpool. As an example, Houlder’s initial concept design for the British Antarctic Survey Vessel RRS Sir David Attenborough specified a moonpool and integrated Launch and Recovery Systems (LARS) for a range of ROVs.
Conversions, older ships and ad-hoc projects require retrofitted back deck systems. Houlder often works with its clients on such projects. As a halfway house, a back-deck A-frame system can be installed in a purpose built hangar. This provides protection from the elements, but at far reduced cost and complexity compared to a built-in system. We also recognise project time and resource pressures, so the bulk of our work is simpler back-deck solutions too. Our installation engineering and design packages have been developed and streamlined over the years to ensure we can respond quickly to requirements.
Engaging with third party help gives any client a head-start in any mobilisation. The goal being a safe, fit for purpose and cost-effective solution delivered on time. This means having awareness of long lead items, in-house calculation packages ready to go and the ability to design and engineer any required deck modifications and sea-fastenings. Power requirements, access walkways and other associated equipment all need to be considered in a fast and effective manner. It is not uncommon, in the case of Houlder, to have the engineering package ready in a week from the issue of any order.
As ROVs continue to develop, the core skills required to launch and recover them will change little in the short to medium term. There are still considerable benefits to engaging with specialist design and engineering expertise prior to any mobilisation project. The key measure of success is having your ROV at work when and as you need it.
Contact James Smith through [email protected] or +44 (0)1224 702 200 for more information on how we can support your ROV projects.