Aberdeen’s All Oceans Engineering has developed a new ROV platform, offering exceptional depth and work capabilities in a package size never previously thought possible
ROVs, as with many technologies, are becoming smaller, lighter and more capable. Driven by the offshore and marine industries – shipping, oil and gas and renewables in particular – they are performing more tasks, more quickly than ever before thanks to a combination of technical improvement and falling costs.
Despite those advances, however, most manufacturers have stuck to the conventional definitions and capabilities of ROV classes – from micro and mini, through to general, light work and heavy work classes.. Yet a breakdown of the fundamental roles required from ROVs aimed at exploration and discovery led Aberdeen engineering firm All Oceans to re-think what such systems should be capable of.
The team identified that such a system must be able to: deploy; locate; observe; sample and recover.
Among other things, that means the system can record accurate positional reference data. To do that properly, they then questioned how large such a system needs to be to perform these functions at all required depths– or, reversing the problem, they wondered how small they could make it.
Smaller ROVs have innate benefits to the offshore industry. As Brian Abel of All Oceans points out: “Small systems don’t need big support vessels or bags of power. Smaller also means lighter, so they’re easier and less expensive to move around the world. Going small also means reduced capital cost and ongoing operational costs.”
Building on the company’s existing ROVs, launch and recovery systems (LARS) and tether management systems (TMS), All Oceans undertook 3 years of development to fit those deepwater capabilities into a small package. The resultant innovations – the MAC-ROV combined with the company’s SHUTTLE concept for varying payload – are now heading towards commercial operation.
The MAC-ROV is supplied for various depth ratings, from 300m to 6,000m for ultra-deepwater exploration. It is a 508mm cube (20”) and powered by 8 thrusters – 4 horizontal, 4 vertical – all brushless DC motors, which provides full 6 degrees of freedom with 23kg (50 lbf) fore, aft, port and starboard and 17kg (38 lbf) in the vertical.
As standard, the MAC-ROV is equipped with a forward-facing 4k camera, and 3 further 1080p HD cameras –2 forward and one rear-facing – with the telemetry to handle all feeds real time simultaneously from 6000m. Lighting is provided by pairs of 1,700-Lumen camera tracking and dimmable LEDs.
For shallow water missions, the MAC-ROV can be deployed on a 300m tether, in a system package with a package weight of around 150kg.
A separate LARS consisting of a winch and telescopic A-Frame is available for deeper system running the MAC-ROV with its TMS or a SHUTTLE package. This is load rated for 1.2Te payloads with a 3g dynamic factor, and 2Te with a 1.8g dynamic factor. Both winch and A-Frame are the same for all systems to 6000m, the only difference being the length of the umbilical on the winch.
Yet the system is most flexible when on deeper operations. Conventional 6,000m ROV systems require a deck’s worth of extra equipment, and weigh in the region of 40 tonnes. Various specifications of winches, TMS and LARS, as well as control rooms and spares workshops – either skid-mounted or housed within the vessel itself – will take these packages to around 40 tonnes.
For work at 1500m - 6000m, the MAC-ROV is supplied with all the required support infrastructure – TMS, winch, racked controls and interconnects etc. – as separates, which are configured and shipped in a one-trip 20-foot ISO container. These can be set up on-site as required.
Alternatively, the system can be shipped fully integrated into the container, including a 3m reach telescopic LARS, an air-conditioned 2-man control room with a window on the LARS and a small workshop. Excluding the container, this entire system weighs 5 tonnes, and requires peak power of 25kW, a fraction of the 40-tonne and three-figure kW power required by 6000m systems that All Oceans have delivered LARS and TMS for in the past.
Abel told InnovOil that prices for systems would be available in Q4 2016, when orders will be taken against deliveries mid-2017. The MAC-ROV will also be available packaged with a TMS as a fly-out package – an offering which the company expects to be of significant interest to industry users.
As with its existing range of ROVs – including the AC-ROV 100 and 3000 –the MAC-ROV will be available as a fly-out vehicle, as well as a standalone system, offering increased versatility. Deployed from the surface, the MAC-ROV can be used to survey and access a dive area before deploying a larger submersible, such as a trencher or mining machine. The ROV and TMS can then be attached to the larger submersible to operate as a fly-out or buddy, on a 100-300m tether.
This allows it to show further perspective on tool deployments and a more mobile overview of operations, reducing risk and increasing productivity. As a scout it can survey areas and situations where the larger host vehicle cannot go, or where risks are higher, for example examining pipe work, wreck inspection, thermal vents etc. It is understood that insurance cover for high-risk operations can be difficult to obtain or prohibitively expensive, so this is where a less expensive asset comes into its own.
The ability to use the MAC-ROV as a fly-out also leads to the company’s new subsea concept: a shuttle. “If you have an ROV and a TMS, then together they make up the submersible package. Our solution is to spread the functionality across these two elements to best advantage. Instead of a TMS, our solution is to use a shuttle,” explains Abel. “This is the key to getting around the need for a big ROV system and guessing what size and power of ROV relative to the tools that it may have to carry.”
This SHUTTLE, in its simplest form, is an open frame that can be loaded with payload items suited to the operation so that all of the work plan can be achieved in a single dive. The frame can be fitted with thrusters, cameras and lights as required for increased capability such as controlled landing for heavier ground work. The MAC-ROV would then be deployed as a payload item and operate as a fly-out.
Mission-specific payloads could be for sampling, coring, bathymetric survey, load recovery etc. In this way, the Shuttle can be configured with as little or as much functionality as needed. It takes a long time to deploy and recover from depth and each dive adds running hours to handling equipment so the more that can be done on a dive the better.
The company foresees the concept being used in several operating modes: survey, observation or lander. The Shuttle would typically have powerful, downward-facing wide-scan and bathymetric sonars, allowing to it perform acoustic monitoring on the terrain from a safe height above the seabed. Large areas could then be surveyed quickly, with further visual inspections being carried out by the fly-out MAC-ROV when required. When landed, the in-water weight of the shuttle would anchor and stabilise it for heavier duty tools to react off. These could be small rock corers or manipulator type sample and artefact recovery tools.
All Oceans qualified the concept for underwater operations early in 2016, two years into its development programme. Abel said that this year will see the first elements built, demonstrated and market-ready – meaning 2017 is likely to be a big year for the diminutive ROV.
Contact: Brian Abel, Managing Director Tel: +44 (0) 1224 790100 Email: firstname.lastname@example.org Web: www.ac-cess.com