Energy News recently toured the Skandi Protector when it was docked in the Port of Fremantle, before setting sail under contract on the North West Shelf, and had a chance to see some of the video from remotely operated vehicles piloted by DOF over the HMAS Sydney shipwreck site as operators showed off the vessel's capabilities.

The DP2 construction support vessel equipped with two state-of-the-art 3000m-rated ROVs, has a complete in-built survey and inspection suite and a 140 t active heave compensated crane allowing it to efficiently undertake subsea IMR (Inspection, maintenance and repair) projects.

The ROVs were piloted over the wreck of the HMAS Sydney to capture high-definition video.

The Skandi Protector, which is has been better known known as the Ocean Protector in Australia while it was under contract with the Australian government's contentious Operation Sovereign Borders, recently replaced its two deck-mounted .50 calibre machine guns with a new saturation diving spread.

Built in 2007 as the MV Geo Bergen, the multi-purpose offshore support vessel was under contract with Australian customs between 2010 and earlier this year.

It has been refurbished with the saturation diving spread and the two new XLX work class ROVs.

The 1100sq.m back deck can be readily reconfigured to lay flexible flowlines and umbilicals for subsea step out developments, install medium sized structures in deep water, undertake air diving operations and many other tasks.

While in Fremantle it took a matter of days to install the D300 saturation diving system that will support a 12-person 300m seawater depth rated system deploys saturation divers by means of a single three-man side launch diving bell.

The system includes a hyperbaric rescue capsule to support the saturation dive team for 72 hours and a highly efficient gas recovery system which ensures economic use of diving gases.

The vessel has been chartered by Chevron Corporation under a three-year master services agreement IMR contract to work on projects on the North West Shelf.

The contract together with the seven-plus-three year IMR contract won by DOF earlier this year will strengthened our market position, engineering and supply chain capabilities in the Asia-Pacific region and support further growth in the region.

The Skandi Protector's involvement with the investigation to the Sydney happened earlier in the year.

Scotland's Ashtead Technology donated specialist subsea equipment, for use on the vessel in a bid to discover exactly what caused the loss of 645 crewmen when the HMAS Sydney sunk on November 19, 1941.

In addition, Ashtead, which is in the business of subsea equipment rental, sales and services to the offshore industry, provided 3D survey equipment to study the wreck and inform conservation of what is a mass grave site.

The vessel had gone missing following a battle with the German cruiser Kormoran, which also sank.

It was never known why the Australian ship went down so quickly when it was pitted against a relatively small opponent.

The final resting place of the HMAS Sydney was only discovered in 2008 off the Western Australian coast in 2000m of water.

Ashtead became involved after being approached by DOF on behalf of the Western Australia Museum which has been working with Curtin University.

The specialist technical equipment supplied by Ashtead allowed researchers to carry out subsea surveys with navigation at depth, studying water speeds, sampling water conditions and providing depth and distance information.

The technology provided included an iXsea ROVINS System, Valeport BFM 803 Current Meter, Valeport MIDAS CTD, Valeport MIDAS BathyPack 3000m, Tritech PA500 Bathy Altimeter, Teledyne Blueview P900-130, and a PMAC CPacq single cell system.

With more than 70 years of mystery around precisely what happened, the survey work was able to show the ship had a 15-centimetre shell hole through the compass platform at the bridge.

The damage would have disabled the control systems and meant the HMAS Sydney would subsequently struggle to defend itself.

Investigators are now assessing how the vessel has corroded and ways that it can be conserved.

"The mystery of what happened to the HMAS Sydney has been a puzzle that led to many different theories over the years. I am glad we could help the families and descendants of those who died on that day to learn just what happened," Ashtead regional manager Wendy Lee said.

"The technology we supplied played a key role in surveying the wreck, establishing the state it is in and what the sea conditions are around it. This is work we are well used to at Ashtead through our support for the offshore industry and the systems used have meant those investigating what happened to the vessel have been able to build up an accurate current picture of the HMAS Sydney and its past."

The survey work on the HMAS Sydney was all done from the outside of the vessel to protect the integrity of the grave site.