Drives & Controls July / August 2022

40 n TRANSPORTATION July/August 2022 www.drivesncontrols.com World’s fastest electric ship enters service in 2023 T he world’s fastest electrically-powered ship is due to enter service in Stockholm next year, potentially heralding a new era for transport. The hydrofoiling electric ferry, called the Candela P- 12 Shuttle, will slash emissions and commuting times. The Swedish city believes that the boat will make waterborne public transport more attractive than trains, buses or cars. Candela, the Swedishmarine technology company developing the 30-passenger vessel, claims it will be the fastest, longest-range and most energy-efficient electric ship ever. It will shuttle passengers between the Stockholm suburb of Ekerö and the city centre at speeds of up to 30 knots – faster than any other electric boat in the world. It will also be quicker than travelling by car, subway or bus during rush hours, andmuchmore energy-efficient than the diesel vessels that currently ply the route Three carbon fibre wings extending from under the hull will act as hydrofoils to lift the ship above the water, thus decreasing drag. This technology will cut energy consumption per passenger-kilometre by 95% compared to conventional vessels, and give the 12m-long boat a range of 50 nautical miles (93km). The energy consumption of 0.1kWh/passenger-km makes the ship more energy-efficient than a hybrid electric bus. With charging rates of up to 200kWDC, the vessel’s 180kWh battery can be charged in less than an hour. The journey between Ekerö and the city centre currently takes 55 minutes by bus, subway or conventional ferry. The Candela P-12 Shuttle will cover the 15km route in 25 minutes, saving commuters an average of 50 minutes per day. Because the hydrofoiling vessel creates almost no wake, it has been granted an exemption from Stockholm’s 12-knot speed limit, allowing it to“fly”into the city centre without causing wave damage to other vessels or shorelines. The propeller wash is claimed to be much smaller than the wake from slow- moving conventional passenger ships. The ferry will be propelled by two permanent magnet motors with counter- rotating propellors. Candela says they will deliver 80% propeller efficiency, compared to 70% for conventional outboard motors. The patent-pending C-Pod motor is claimed to be the first electric pod motor designed for high-speed boats. The direct, all-electric drive reduces friction and provides 23%more range than the best electric outboards. The custom- designed motors are said to achieve power densities four times higher than rivals. The motors need no maintenance and will operate for 3,000 hours without a service. There is no need to change oil or cooling fluid because the sealed motors are cooled by the flow of seawater. And because the motors operate underwater, they avoid the usual noise from gearboxes and mechanical transmissions. A computer regulates the hydrofoils 100 times per second, ensuring a smooth ride over waves, even in adverse conditions that might make some passengers feel seasick in conventional vessels. It will feel more like being on a modern express train than on a boat, says Erik Eklund, Candela’s vice-president for commercial vessels. The first P-12 will operate in Stockholm for a nine-month trial period during 2023. If it lives up to expectations, the plan is eventually to replace the city’s fleet of more than 70 diesel vessels with the electric shuttles. Candela hopes that its electric ferry will mark a comeback for waterborne transport in cities such as Venice, San Francisco and NewYork, where the waterways offer natural cross- connections between regions and boroughs. In rush-hour traffic, the ferries will be faster than buses and cars on many routes and can compete on mileage costs too. Unlike new subway lines or roads, electric ships can ply new routes without massive infrastructure investments – all they need is a dock and electric power. The shuttle’s 30-passenger capacity will add to its versatility. In Stockholm, ferries have an average occupancy rate of 17%, so a typical 300-passenger ship carries only about 50 people on most days. The faster electric ferries will allowmore frequent departures and higher occupancy rates, at a lower cost to operators. On the Ekerö-Stockholm route, Candela wants to replace two existing 200-passenger diesel vessels with at least five shuttles, doubling the potential passenger volumes and cutting operating costs. Instead of two departures per day, the shuttles could leave every 11 minutes, allowing commuters to ignore timetables and just turn up at the dock for the next boat. Candela plans to lay the carbon fibre keel for the first Candela P-12 Shuttle at a new, automated factory in Rotebro, outside Stockholm, towards the end of 2022. The first commuters in Stockholmwill start to travel on the 8.5-tonne vessel in 2023. As production ramps up, Candela aims eventually to produce hundreds of shuttles every year. More than 600 cities, municipalities, vessel operators and urban developers have already expressed interest in the boats as a faster, cheaper, and greener alternative to existing diesel ships or land transport. n An electrically-powered hydrofoil ferry that can travel at up to 30 knots, is due to enter service in Stockholm next year. Its developers say that it will be faster and more energy-efficient than trains or cars and could change the way we commute. The electrically-powered hydrofoil ferry will travel smoothly at speeds of up to 30 knots over distances of up to 50 nautical miles