For the 10th instalment of its Annual International Student Design Competition for a Safe, Affordable Ferry, spanning 2022-2023, the Worldwide Ferry Safety Association (WFSA) shook things up by introducing a new stipulation for the participating teams. Although previous years’ contests had called for ferry designs to meet specific operational demands, the panel of judges had “always been neutral about the power source” of the students’ proposed designs, Dr Roberta Weisbrod, WFSA executive director, announced last year.
This time round, though, the students would have to develop an electric-fuelled ferry for the Pasig River in Manila, in line with ongoing efforts to decarbonise public transport across the capital. Vessel spec criteria included the capacity for 100 passengers (as well as bikes, baby strollers and luggage), with three stops on the Pasig River, and the vessel would have to be affordable to construct, acquire, operate, maintain and repair.
The curveball of electric propulsion created a fresh challenge for the teams, who would now have to consider the availability of shoreside chargers, battery handling-related safety and the risk of loss of power. And then, there were the unique characteristics of the Pasig River itself: a tidal estuary with tidal variation of approximately 1.5m, prone to strong currents and rising water levels during the June-November monsoon season.
In total, the WFSA contest attracted 16 entries from academic institutions across Asia, Europe and the Americas. The City University of Applied Sciences, Bremen was declared the winner with its CAT|abao concept: a 22m aluminium catamaran, deemed by the judges to be “solid in virtually all respects, with a great attention to detail”.
Team leader Laurin Rösemeier tells Ship & Boat International: “We had to acquire a lot of knowledge at the beginning, especially in the field of battery and electric propulsion technology.” This involved the team contacting electric drive company Baumüller and battery manufacturer Corvus Energy for assistance with the design of the powertrain. “We realised early on that we would not achieve the service life we had aimed for with the battery power we had initially installed,” Rösemeier continues. “Thus, in the advanced design phase, we suddenly needed much larger battery capacities, which brought with it many difficulties regarding our weight management.”
The CAT|abao would measure 22m x 7.3m and draw approximately 0.95m. “In normal traffic mode, we can carry up to 100 passengers, two wheelchair users and three crew members,” Rösemeier explains. However, with the potential for passenger overcrowding in mind, the Bremen team designed the CAT|abao for a safe and stable working limit of 195 persons in total. To protect this complement, the ferry would carry twin 150-person liferafts, situated fore and aft, plus eight buoys and 217 lifejackets.
The Cat|abao concept is 100% electric, with no diesel genset back-up. The direct propulsion system includes: a pair of three-phase synchronous Baumüller electric motors, rated 235kW apiece; a six-pack of Corvus Dolphin NG batteries, rated a combined 754kWh; and twin four-bladed, 600mm-diameter, fixed-pitch propellers. The Corvus battery set-up comes with a thermal runaway protection system and an inert gas and high-pressure water mist system, and would be housed in an A60 insulated battery room, monitored by thermal imaging cameras.
(For the full, in-depth article and the e-ferry’s technical particulars, check out Ship & Boat International July/August 2023)
