Candela P-12 taking off – Electric hydrofoiling passenger vessel [video]
Electric hydrofoiling ferries like the Candela P-12 promise drastically lower energy use and emissions by lifting the hull out of the water, enabling fast, quiet passenger transport on batteries. Commenters probe how well this works beyond glossy promo footage, focusing on real-world constraints such as wave height limits, debris impacts, control complexity, and the difficulty of scaling to larger, rough-sea vessels. Many see strong potential in sheltered waters—bays, lakes, rivers, and archipelagos—where shorter routes, wake restrictions, and local pollution concerns could make these boats economically and environmentally attractive replacements for small diesel ferries and water taxis.
Wave handling and seaworthiness
- Many focus on the flat water in the promo video and question performance in rough seas.
- Linked videos show smaller Candela models in choppy conditions; consensus: smoother than conventional boats at similar size, but “extreme weather” in marketing is viewed as overstated.
- FAQ and company comments: C‑8 foils up to ~1.2 m waves; P‑12 up to ~2 m and can run as a catamaran hull at ≤10 knots when foiling isn’t possible.
- Several note that open oceans often exceed these wave heights; hydrofoils are framed as littoral / inland craft, not blue-water vessels.
- Some first‑hand experiences describe software-triggered “hard landings” in >1 m chop and anxiety about being dependent on the control system.
Use cases and geography
- Main target: lakes, bays, rivers, archipelagos (e.g., Stockholm, Oslo fjord, Venice lagoon, Great Lakes, Puget Sound).
- Many short, passenger‑only ferries and water taxis (10–30 pax) in Nordic and other coastal cities are cited as natural fits.
- Questions arise about whether very short routes offer enough distance to benefit from foiling; others cite existing hydrofoil ferries on similar-length routes as evidence they can.
Efficiency, economics, and environment
- Hydrofoils reduce drag dramatically (one estimate: ~1/6 of conventional hull drag), which is crucial for electric range.
- Company claims: ~80% less energy than conventional vessels, ~50% lower total operating cost including energy, service, and salaries; uses up to 175 kW DC charging instead of MW‑scale shore power.
- Discussion notes ferries are described as highly polluting; some are surprised but no detailed counter-data is provided.
Safety, debris, and failure modes
- Logs, kelp, and floating debris (common in some regions) are a major concern; impacts can be catastrophic for foils and passengers.
- Past hydrofoil projects reportedly struggled with debris and even whale strikes.
- Some say strong foils can “whack” smaller logs aside; others note very large trunks would be problematic.
- Basic failure mode is still “it floats” once off-foil, but ride comfort and efficiency drop sharply.
Technology and control systems
- Vessels use submerged foils with active control: sensors measure waves and attitude; a “flight controller” adjusts foil angles up to ~100 Hz.
- This is contrasted with older surface‑piercing hydrofoils that lacked digital stabilization and were more nauseating.
- Observers spot FreeRTOS, CAN bus, CANopen, and C++-based control code; displays may run something heavier (Grafana‑like UI, possibly Linux).
Comparison to historical and other hydrofoils
- Thread recalls Soviet, Mediterranean, Japanese, and North American hydrofoil ferries from the 1960s–1990s, many retired due to cost, reliability, fuel use, and sea‑state limits.
- View: electric propulsion plus modern control electronics may shift the economics, but hydrofoils still don’t scale well to large, heavy ships.
- Competing projects (e.g., Navier) are mentioned; some prefer their design aesthetics but see similar tradeoffs.
Business case and open questions
- Skeptics question ticket prices given 12–30 passenger capacity and high capital cost (~€1.7M).
- Proponents argue higher speed and low operating cost can justify smaller capacity and frequent service, especially on dense commuter routes.
- Unclear: long‑term maintenance costs, robustness in debris‑heavy waters, and real‑world reliability versus traditional ferries.