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VOLTA on a power trip

Ship & Boat International eNews: February 2021



Austal Australia has unveiled its VOLTA ferry concept, which is set to comprise a series of battery-powered, all-electric passenger catamarans capable of top speeds in excess of 25knots. The VOLTA class will include vessels of varying sizes and capacities, ranging from a 32m, 250-pax version to a 46m, 450-pax version.


The latter of these, the Passenger Express 46V, is the first family member to have been revealed. This 46m x 12.3m model features a draught of just under 2m, and, in addition to its passenger complement, has the capacity for three crew members. 


Specifications for the VOLTA series include lightweight and low-resistance hullforms, which have been designed and tested, over the course of two years, for optimal performance when combined with electric propulsion. Austal CEO Paddy Gregg states: “For any high-speed vessel, and even more so for electric-powered ferries, optimising vessel weight and performance is essential – driving not just operating costs, but the size and upfront purchase cost of the batteries and the charging system.”


Gregg adds: “[The] VOLTA series also future-proofs an operator’s fleet by introducing environmentally friendly technology that already meets widely anticipated, low- or zero-emission targets for public transport vehicles and operators, worldwide.”


The propulsive arrangement of the Passenger Express 46V includes two fully electric permanent magnet motors and a pair of propellers (either controllable- or fixed-pitch), although customers can also specify waterjet or azimuth options. Each of the cat’s hulls will accommodate a lithium-ion battery bank, featuring a minimum battery life of seven years. Austal's Jamie Anderson, who is part of the VOLTA development drive, tells Ship & Boat International: "The OEMs are not firm: however, the proposed designs show Danfoss for the motors and Leclanché for the batteries." He adds: "We wish to remain flexible, as the suitability of OEMs' products will be highly dependent on each vessel's route / operating profile."


The ferry has also been developed for a daily range of more than 175nm, and for rapid shoreside charging. Its expected service speed will be around 20knots.


Aesthetic considerations include large, panoramic windows and skylights, which will run the full length of the passenger cabin to create a light-filled interior. Austal says: “Double automatic-sliding external doors provide direct, easy access to the passenger deck for fast passenger turnarounds that [will] match or better the succinct battery-charging times offered by the fully integrated, shore-based battery charging infrastructure.” The Passenger Express 46V will also offer storage space for up to 10 bicycles.


The VOLTA cats are chiefly being promoted as economical vessels for inland waterway commuter runs, although Austal hints that the concept could also be applied to commercial and defence applications, including autonomous vessels, in the future.