• The Bluebottle prototype undergoing trials recently on Lake Macquarie. Credit: Ocius Technology
    The Bluebottle prototype undergoing trials recently on Lake Macquarie. Credit: Ocius Technology

Patrick Durrant | Sydney

Following its launch in December last year, Ocius Technology's Bluebottle Stinger unmanned surface vessel (USV) has been undergoing trials in the lead up to a CTD program demonstration in August.

In 2015, Ocius teamed with aerospace and defence electronics company Thales to win DST Group Capability Technology Demonstrator funding to develop a USV suitable for ASW. The prototype, christened Bruce and developed in conjunction with Steber International, has been put through its paces since February in the enclosed waters of Botany Bay and Lake Macquarie, but will soon be trialled in the open waters off Jervis Bay.

ADM spoke with Ocius Technology CEO Robert Dane who said they were ahead of schedule for the pre-CTD trials and the protoype was achieving if not out-performing the key performance  indicators (KPIs) that had been set.

“Our speed KPI is 5 knots and we're doing six; we've got to sail within 50 metres of waypoints and we're sailing right over them; we're also exceeeding the sea state requirements,” Dane said.

The 5.6 metre Bluebottle has been designed to carry a 105 kilogram payload which includes a winch, cable and a towed array or 'Stinger' developed by Thales. The array will be provided by Thales in May and  Dane said that to date they had been towing drogues that replicated the drag measurements provided by Thales. An equivalent weight has been used for the proposed winch, which will also be fitted along with the array for the Jervis Bay trials.

“It's not a significant drag, in fact during the trial on Botany Bay the boat seemed to be performing normally and I had to question whether the drogue had parted from the cable!” Dane said.

The Jervis Bay and open ocean trials planned in May will further test the ability of the Bluebottle USV to perform to requirements. Dane confirmed the prototype had thus far been exposed to winds up to 25 knots in enclosed waters, but saw no reason why increased swell or wind conditions would hamper the performance of the craft.

During the Lake Macquarie trial the Bluebottle's solar panel mast and power management system were tested and despite skies being overcast for 11 out of the 12 trial days, the diffuse light provided the solar sail and deck panels with power ranging from 100-350 watts.

"Even on an overcast day, there's all this light that bounces between the cloud and the water –  we were really pleased with the amount of solar power we were harnessing but also the amount of power being used by the boat.”

With recorded morning battery levels indicating 80 per cent charge and the evening levels around  93 per cent, Dane felt satisfied the craft could operate sustainably for a very long period of time.

“Theoretically it could operate for ever but the long-term effects of bio-fouling would counteract that.”

The team had also conducted successful collision avoidance trials on the lake using automatic identification systems (AIS) commonly used by merchant shipping.

“In the enclosed waters we had to apply geo-fencing so Bruce wouldn't venture into shallow water or navigation hazards, and then we approached it on a collision course with our support craft equipped with an AIS. Bruce demonstrated it was able to take avoiding action while at the same time staying clear of other hazards.”  

Ocius was also developing visual recognition software as a collision avoidance measure despite this not being a KPI for the CTD. 

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