Flooded tunnel inspection record broken by Hibbard Inshore using a Saab Seaeye Sabertooth


Flooded tunnel inspection record broken by Hibbard Inshore using a Saab Seaeye Sabertooth

Inside Australia's Snowy Mountain hydro scheme, leading underwater service provider, Hibbard Inshore, say they have broken the record for the longest tunnel inspection by a tethered vehicle using their newest long-range vehicle, the Saab Seaeye Sabertooth.

Importantly, this meant there was no need to drain the tunnel system, which saved closing down several power stations.

During a round-trip of over 24 kilometres, Hibbard Inshore's customised Sabertooth AUV/ROV collected real-time visual data whilst scanning the tunnel with multiple types of multibeam sonar.

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Sabertooth entering flooded tunnel
Sabertooth entering flooded tunnel.
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Field control tent
Field control tent.

The mission set out to gather high-density dimensional data, discover open cracks or holes, find debris build-up, detect lining failures, and identify any rock falls.

From the data collected Hibbard created 3D models ready for maintenance planning and comparable inspection data to identify future trends in tunnel condition.

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Tunnel sonar cross-section
Tunnel sonar cross-section.

Hibbard Inshore has so far inspected six trans-mountain tunnels across the Snowy Hydro Scheme using this method and will return in 2014 for further inspections.

Previously the tunnels had to be drained for examination, risking collapse of the tunnel and endangering inspection personnel.

Chief Operating Officer of Snowy Hydro, Ken Lister said:

"The use of the unmanned sub for tunnel inspections now means that it can be done more frequently, more safely and without the need to shut down power stations or drain the tunnel. This multi-million dollar investment is a great outcome for the business, for the safety of our people and contractors and is part of our wider program of Scheme upgrades and on-going maintenance".

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Sabertooth single-hull AUV/ROV
Sabertooth single-hull AUV/ROV.

The challenges for Hibbard Inshore included entering narrow shafts, navigating tight bends, working in limited visibility and managing within a strict schedule.

The Sabertooth can operate as either a remotely operated vehicle (ROV) with a tether to allow for real-time data and pilot control, or as an autonomous underwater vehicle (AUV) to give flexibility in various tunnel inspection scenarios.

Saab Seaeye is the world's largest manufacturer of electric ROVs, and now includes Saab's underwater vehicle range of tethered, autonomous and hybrid underwater vehicle systems for the defence industry.

Hibbard Inshore is a global engineering services company with a premier fleet of ROVs and the expertise and technology necessary to solve the complex challenges of the power, water, sewer, tunnelling and offshore industries.

For more information contact:

Dave Malak
Hibbard Inshore
+1 248 745 8456

Matt Bates
Saab Seaeye Limited
+44 (0)1489 898 000