The Economist has noted a seemingly novel yet potentially transformative technology for urban transportation: electric hydrofoils. On the surface, these vessels appear to ‘fly,’ but the true significance lies not in their visual appeal, but in the fact that they provide a long-missing transportation option between railways and ferries.
Hydrofoils are not a new invention. For Hong Kong residents, the Hong Kong-Macau high-speed ferries have long dominated cross-border travel. Before the opening of the Hong Kong-Zhuhai-Macao Bridge, water transport was almost the only high-frequency, predictable, and timely option available. With speeds exceeding forty knots and a travel time of nearly one hour, they facilitated significant human and economic exchanges between the two regions. Hydrofoils were not rendered obsolete by technology; rather, they were replaced by an extremely costly bridge.
However, the Hong Kong-Zhuhai-Macao Bridge is an extreme case. Building a bridge of this nature involves artificial islands, environmental assessments, long-term maintenance, and risk management, with costs often reaching hundreds of billions. Such investment levels are simply not replicable for most cities. In areas where giant bridges cannot be constructed, water transport often remains ‘logically sound yet unfeasible.’
The resurgence of electric hydrofoils stems from the simultaneous maturation of several technologies rather than a single breakthrough. First is battery technology, which, despite still having limited energy density, is sufficient to support stable cruising speeds of twenty-five to thirty knots, ideal for urban and suburban routes. Next are sensors and control systems, which allow modern hydrofoils to adjust wing angles in real-time, actively compensating for waves and significantly enhancing stability. Additionally, composite materials make the hull lighter and the structure simpler, thereby reducing maintenance costs. Electric propulsion also brings low noise and vibration, making high-frequency services more acceptable in urban environments.
Applying this logic to the geography of the UK clarifies its effects. Take Cardiff, the capital of Wales, and Weston-super-Mare in England as an example. The water route between the two is not far, but the land route must detour through the area around Portishead, resulting in delays whether by car or train. If electric hydrofoils were to operate direct services, the journey could be kept to just over thirty minutes, potentially compressing the door-to-door time to under forty-five minutes. The reason such routes have long been neglected is not due to a lack of demand, but because past vessels were too slow and bridges too expensive.
Similar situations exist between Portishead and other towns, as well as between Liverpool and Wirral, and various towns downstream of the Thames in London. Water routes have always existed but have never been considered a primary mode of transport. Railways cannot overcome geographical limitations, roads only exacerbate congestion, and bridges far exceed financial capacities. Electric hydrofoils do not need to replace any existing systems; they merely need to serve as tools to ‘straighten routes’ to change certain commuting patterns.
The true significance of electric hydrofoils lies not in a race for speed, but in reminding cities to reassess their geography. When a bridge is too expensive, a road too convoluted, and water surfaces readily available, the options may never have been lacking; rather, we simply have not used the right tools.
