StarFish sonar scans seabed

An innovative sonar device aims to give scientists photo-quality images of the seabed for surveying dive sites or conducting underwater research

StarFish, an innovative sonar device recently launched in the UK, aims to give scientists photo-quality images of the seabed.

StarFish is a high definition side scan sonar, currently the smallest side-scan tow fish – so called because it is towed behind a vessel – on the market.

The device uses sonar to ‘see’ underwater to a much greater depth than the human eye. It transmits small pulses of sound, which are absorbed and reflected back by the seabed and other underwater objects. The strength of each returned pulse together with the time the pulse travelled can provide a digital underwater picture. Side scan sonar is specifically used to view the seabed and any structures or objects laying on it.

Designed and built by an Aberdeen-based partnership of Tritech International and Blueprint Design Engineering, the plug-and-play StarFish can connect to any PC or laptop via a USB connection, allowing it to be used with accompanying easy to use software to show the seabed.

To produce it, Blueprint Design engaged Folkestone’s Martello to produce a vacuum cast over-moulding using their Thin-Rim polyurethane elastomeric resin. It had to enable the metalwork and electronics of the StarFish to be encapsulated in the resin and still enable the device to operate.

Using rapid manufacturing and vacuum casting technology, Martello’s engineers designed an SLA (Stereo Lithography Apparatus) master and silicone tool with which to manufacture the over-mouldings. Martello initially produced six StarFish over-mouldings, which were rigorously tested before the product launch in June 2007.

Potential applications for the StarFish include dive site discovery and location surveys, shipwreck hunting and/or treasure hunting. The Coastguard and Law Enforcement or Homeland Security industries could also use it for lake, river or seabed search and recovery operations, navigational hazard mapping, port and harbour structure inspection and reconnaissance applications. Fisheries can also benefit by monitoring the size and location of fish schools and fish density management, and universities and research institutes can use it in geological surveys, maritime archaeology and inspection of coral structures.