The AMS60 side-scan sonar system waits its turn to collect high-resolution sonar images. The yellow blocks are syntactic foam that provides buoyancy for the towfish and the starboard side sonar transducer is located just below the AMS60SI label.

The AMS60 sonar is carefully launched off the Seahorse Spirit's transom.

Secured by taglines the AMS60 sonar enters the waters of the Coral Sea. When fully immersed the towfish is slightly positively buoyant and at this point the main lift line to the crane can be released.

The Williamson crew and spectators are fixated on the sonar screens as the sonar imagery is slowly revealed.

This high-resolution image of the remaining sonar target shows its ship-like shape and associated acoustic shadow. The target lies in a gulley off one of the main submarine canyons at a depth of approximately 2,000 metres.

Williamson & Associates team of sonar operators at their stations monitoring the incoming sonar imagery. This is where they "fly" the sonar towfish over the seabed by remote control of the large towing winch on deck.

The navigator uses these four screens to plan tracklines, monitor the ship's progress along a trackline and the towfish position relative to the seabed geology.

This work station is where all the sonar targets are analysed off-line and the sonar data is electronically pieced together, or mosaicked, to check for gaps or holidays in the coverage.

The Captain and officers on Spirit's bridge have their own display of the tracklines completed.

Brad Hunt, one of the Dynamic Positioning Officers (DPO) at the helm of the Seahorse Spirit. With the East Australian current running at full force our progress is very much dependent on the ship handling ability of the ship's officers.

When the ship is forced to "crab" down a trackline it puts the towcable over at a severe angle from the ideal centerline position. This photo was taken before the current worsened so the angle is not as great as it was later on.

A sonar image of the first promising target found Monday morning on the first trackline run through the search box. The target is just to the right of centre and can be better seen on the zoomed image.

A zoomed image of target No. 1. The linear shape and overall dimensions of this target is what interests us most as well as the "acoustic shadow", which indicates that whatever this is it is sticking up off the seabed.

This is the fourth sonar target we found late last night and it too has the right shape and dimensions for a ship the size of Centaur.

This zoomed image of target No. 4 shows that it is very hard with a structure that indicates it is possibly man-made.

Aaron Smith uplinks the video footage he has shot to an overhead helicopter via a special microwave transmitter.

A Brisbane based news helicopter has come out to visit us twice since the search began. All the National news broadcasters have agreed to share the pooled video footage shot by Aaron.

This is what many months of research and analysis boils down to. A search box with a grid of primary tracklines that covers the most probable locations for Centaur's wreck. The search box has been reoriented from the original North-South direction to run in concert with the depth contours of the continental shelf. The small unlabelled dots show the position of the two sonar targets.

An image of quite smooth and flat seabed. The dark line running through the right side of the image is actually a sonar reflection from the surface of the sea. There is some geology in this image but not enough to make detecting the wreck a problem.

This image shows just how rugged and rocky one of the cliff tops is and the steepness of the canyon walls. The majority of the right hand side of this image is virtually unsearchable because of the large outcroppings of rock.

This bathymetric map shows just how irregular the seabed is within the search box. The pink/red colours to the left represents shallow water of about 300 metres depth while the purple colours to the right represent the deepest waters of in excess of 3,500 metres. (Courtesy of Dr. Ron Boyd, CSIRO)

Launch of the SM-30 side-scan sonar towfish off the stern of the MPV Seahorse Spirit.

The main working deck of the MPV Seahorse Spirit showing the two large towing winches and the office containers where the search team conducts their work.

Inside one of the office containers.

Google Map showing the size and orientation of the search box in relation to some of the navigation clues to the sinking location of the Centaur.

Sonar image showing the most rocky and mountainous within the northern half of the search box.

Various sonar images of the Kyogle shipwreck at different resolutions. The white strip behind the wreck is an “acoustic shadow” caused by the wreck sitting about 4 metres high off the seabed.

The Seahorse Spirit is expected to depart Brisbane on 12 December 2009 to begin 3 days of testing before the official search begins.