VESSEL REVIEW | Ottalauss – Compact waterjet workboat to support salmon farming in southern Australia

Australia’s Huon Aquaculture has taken delivery of a new general-purpose workboat built by local company Lyndcraft Boats.

Ottalauss was designed by Australia/New Zealand naval architecture firm Oceantech to be capable of supporting Huon’s fish farming operations in southern Tasmania.

The vessel was built for 24-hour operations, in part due to the fact that performing certain routines (such as harvesting) at night would provide a higher level of animal welfare. Abundant deck lighting and adequate deck space meanwhile help facilitate a safe working environment in these conditions, as does a dedicated external helm, which is particularly useful when working in close proximity to pens.

“Ottalauss follows Huon’s Viking-inspired naming tradition of her predecessors,” Oceantech told Baird Maritime.

The designer remarked that the name is a combination of the Norse words ótti (“fear”) and laus (“free from”/”without”), hence the name translating into “fearless” and, “suit[ing] the vessel’s unfazed confrontation with 24-hour operations in the ‘roaring forties’" [strong westerly winds at latitudes between 40 and 50 degrees south of the equator, –ed].

Fast and durable platform built for Tasmania's extreme conditions

Huon’s salmon farming enterprise is characterised by low-density fish pens, resulting in an operation that covers a large swathe across the southern coast of Tasmania. In Oceantech’s view, this means Ottalauss will frequently perform offshore transits to service different farms and to do so safely and swiftly.

“Once at the farm, the range of duties as a support vessel call for a robust work platform. Thus, a compromise to deliver effectively on these fundamental tasks is vital.”

Oceantech explained that Ottalauss is the fourth vessel in a series, as Huon had opted for a proven design enhanced with further refinements.

“Standardisation in a fleet drives efficiency and cost savings, in both maintenance and operational procedures, so the familiar platform of a Cummins-driven Hamilton waterjet boat was a given.”

To minimise transit times in extreme environments without sacrificing crew comfort, a balance needed to be achieved between making the vessel strong enough to endure years of abuse and keeping structural weight within an acceptable limit to achieve the desired performance. Ottalauss therefore boasts 8mm aluminium plating on both the hull bottom and the topsides, up to the main deck, which Oceantech said is a notable upgrade from the 6mm plating on her predecessors.

“Part of addressing the effect of this additional weight was to optimise the local reinforcement of supporting structure for the crane base and capstan winches,” the designer told Baird Maritime. “In doing so, we were able to re-evaluate how to best maximise the usable deck area by limiting any impeding structure.”

Ease of construction ensured by applying methods used on earlier boats

Attention was also paid to the “build-ability” of the vessel throughout. Ottalauss’ construction took advantage of lessons gleaned from previous iterations, built through a partnership between Crisp Bros and Haywards and Oceantech, incorporating minor adaptations, “for a near seamless construction process.”

The vessel is powered by two Cummins QSL9 engines that each drive a Hamilton HJ322 jet via a ZF 325-1 gearbox. This configuration delivers a transit speed of 25 knots, while the application of jets allows for tender manoeuvring around pens upon arrival.

“Such has been the success of this combination [that] future iterations of the vessel are already destined to utilise Hamilton HTX30 jets,” Oceantech remarked.

Adopting and enhancing a proven design and its corresponding fitout

As with Huon’s other vessels that are under 24 metres (79 feet) long, Ottalauss is fitted with a Simrad navigation suite consisting of dual screens for charts and radar. The deck equipment meanwhile includes a Fassi crane.

"As with any design undertaking, compromise was key," said Oceantech. "In this case, an increase in crane capacity, and the commensurate increase in supporting structure, had the potential to impact the vessel’s performance both at speed and at rest. A new custom crane pedestal was designed, with the help of FEA software, to ensure structural efficiency, while a comprehensive stability analysis confirmed there would be no adverse impact on performance."

For Oceantech, the biggest challenge was increasing the thickness and strength of the hull whilst maintaining the baseline speed requirements. On the construction side, because Lyndcraft Boats’ yard facilities were about a four-hour drive from Huon’s worksites, it meant that the build team needed to spend considerable time going back and forth to check on Ottalauss’ sisters and collaborate with the crews on small build improvements.

Nonetheless, the work progressed until the completion and delivery of the vessel, and Oceantech even took the opportunity to further enhance the effectiveness of the series.

“As her sisters have been in service for at least seven years already, we have included design improvements to enable easy servicing of the vessel for Huon’s maintenance crews,” the designer told Baird Maritime. “These improvements, like easy cable runs, will be adopted for future builds.”