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2021-05-09

Saab’s Sabertooth Takes Green Tech to New Depths

Building and operating maritime facilities entails major challenges. These constructions are often complex and can be floating or attached to the bottom. Some are even placed on the seabed. Many are located far from land and at great depths.

Whether it is about wind power, gas pipelines, oil rigs, water tunnels in power plants or electric cables on the bottom of the ocean, they all require continuous maintenance to ensure reliability and smooth operations with minimal disruption and environmental impact.

Attention is focussed on everything from renewable energy and agriculture and fish farms on an industrial scale, to new offshore installations for oil and gas.

Swedish aerospace and defence company SAAB’s intelligent transformative robotic system, Sabertooth, is changing the name of the game by making the work below the surface easier, more efficient and environmentally sustainable.

Peter Erkers, Sales Director at Saab, elaborates: “Sabertooth fits in perfectly. It is ideal for offshore survey, inspection, maintenance and repair (IMR), environmental monitoring, inspection of installations, infrastructure on the sea floor and hydro power plant tunnels in autonomous mode. Its strong, compact format and the built-in flexibility qualify it as a key resource during construction phases as well as for long-term service and maintenance assignments. It can perform anything from routine duties to more complex tasks at depths of up to 3,000 metres. It can be equipped with both acoustic and optical sensors as well as a wide range of tools. ‘A bit like a Swiss Army knife’, as one customer put it.”
Available in single and double hull, Sabertooth is a very powerful but lightweight platform.

Its small size, tether-free operation and manoeuvrability ensure easy and safe access inside and around complex structures. This makes it suitable for offshore survey work and autonomous IMR of subsea installations and tunnels.

It’s true that most underwater projects presently use remote-controlled hydraulic vehicles, but they are associated with environmental challenges, especially in view of the carbon footprints left behind by supply vessels and the risk of oil leakage from their hydraulic systems.

Pushing Underwater Boundaries

Sabertooth, on the other hand, is an electrically powered lightweight hybrid underwater vehicle designed to reduce human, technical and environmental risks. The small size, tether-free operational capability and six-degrees-of-freedom-of-movement manoeuvrability ensure easy and safe access within and around complex structures.

“Sabertooth is the only hovering autonomous system that can operate in both autonomous and remote mode and handle connections in both the horizontal and vertical plane,” insists Peter Erkers.

Built-in Smartness

In autonomous mode, Sabertooth can be programmed to undertake tasks completely on its own, such as routine ones that previously required manual intervention. Sabertooth was also the first craft to connect to a docking station located on the sea floor and send data, be assigned new missions and charge the batteries.

It does this all automatically without the need for human control. It also has a future potential to change work tools. Sabertooth is powered either by battery or tether.

If used as a subsea resident system, the vehicle is housed at the docking unit where its batteries can be recharged. This unit allows data to be uploaded to the surface and new instructions to be downloaded.

Among its most important features, Sabertooth can also swim autonomously to the docking unit and remain there 24/7 for more than six months without maintenance, eliminating the cost of surface vessels.

This deep-water hovering autonomous underwater vehicle (AUV)/remotely operated vehicle (ROV) benefits from 360° manoeuvrability with six degrees of freedom, interfaces for sensors and auxiliary equipment. It utilises advanced autopilot functionality.

Sabertooth has the capability for non-invasive self-diagnostics and includes a fault-tolerant control system. A remote Internet interface is available as a resource for technical support if needed.

Tooling packages can also be stored in the vicinity of the vehicle and used as required. For the ROV mode there is a wide range of winches and tethers available. “It is the only vehicle currently on the market capable of undertaking long-term residency in difficult to access locations. The new docking technology allows the Sabertooth to stay deployed in deep water for more than six months,” Peter Erkers explains.

Wireless Remote Operation

In remote mode, the vessel can be operated manually via a fibre-optic tether or wireless via BlueComm - an optical through-water communication link which is the underwater technology’s equivalent of Wi-Fi, but where optical signals are used instead of radio waves, which work well in challenging underwater environments. Ioseba Tena, Global Business Manager at Sonardyne, a leading global provider of marine technology, is one person who has extensive experience of this type of technology in both theory and practice.

“BlueComm and Sabertooth together provide unique capability. The ability for the AUV to be operated wirelessly by an operator is something I think operators want to happen. They want to know there is a man in the loop. If you can do this wirelessly you have the advantage of the system not getting entangled, which makes it a great tool,” says Tena.

Extreme Challenges

It is known that 70 per cent of the Earth’s surface is covered by water. Much of this vast area is inaccessible to humans due to the huge depths with extreme levels of pressure, permanent darkness, cold, and strong currents. As human divers are unable to go below approx. 300 metres, we have to rely on different types of underwater systems to do the job for us.

This clearly means that working with traditional remotely operated vehicles the operator’s field of vision and the system’s mobility are limited. Also, the wire and the tether that connects the vessel with the surface vessel can become tangled and complicate the work.

Conversely, autonomous systems, or those that can be operated wirelessly, make it possible to work more efficiently, operate the system with greater precision, and have a significantly smaller environmental footprint.

This is how Andy Baker, AUV and Survey Lead formerly at Modus Seabed Intervention and now 3D at Depth, both companies that use the Sabertooth platform - puts it: “I suppose looking at it from the survey point of view, due to my background, it is a very stable and capable platform. It has six degrees of freedom of movement so we can get a good visual, good coverage of data. And being stable and fast means we can get a better quality of data quicker with less people because it is an autonomous platform.”

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