Fàng Sōng, a 14.69-metre houseboat redesigned by Berlin architecture studio Crossboundaries, combines a compact, flexible interior with a solar-electric propulsion system. Crossboundaries reports that on sunny days the boat can travel about 50 km at an average 7 km/h. The studio also says it typically relies on solar power from March through November, while electric shore connections supplement power in winter.
The project at a glance
Crossboundaries describes Fàng Sōng (放松), translated on its project page as “Relax,” as a retrofit and interior-design project for client Marianne Friese. Located at Stößensee in Berlin, Germany, it was completed in July 2022. The studio lists an interior gross area of 62 square metres, a length of 14.69 metres and a maximum width of 4.24 metres. It says the boat accommodates up to two people, plus guests, with rooms designed to serve more than one function. Crossboundaries’ project page
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Friese bought the five-year-old boat in 2020 and worked with the studio to turn it into a mobile retreat. Crossboundaries describes a goal of practising locally, obtaining the relevant licence and eventually travelling toward Paris and southern France. Those are ambitions for future journeys, not evidence that the trips have taken place.
How solar power supports the boat
Crossboundaries says solar panels cover the roof, with one additional panel on each side. Large battery storage supplies the engines, appliances and the boat’s technical needs. The studio reports that Fàng Sōng can travel approximately 50 km per sunny day at an average speed of 7 km/h. This is the project team’s operating claim, not an independently verified range figure: the project page does not publish the array’s wattage, battery capacity, motor model, route, payload, weather conditions or testing method.
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The seasonal qualification matters. According to Crossboundaries, the boat is usually self-reliant from March through November and on sunny winter days; electric shore connections supplement its power in winter. The project account therefore does not describe year-round independence from shore power.
A compact interior and onboard systems
The tiny-living idea is expressed through flexible use of the available space rather than a claim that the boat functions like a full-sized house. Crossboundaries says rooms can serve multiple functions and that the layout accommodates the owner and guests. A pellet stove provides heat, with pellets stored below the floor. The studio describes a water-purification system and biological sewage-treatment unit as future plans, not as installed features.
The project page frames the boat as more than a private dwelling. Crossboundaries co-founder and partner Binke Lenhardt describes it as “a unit of the city” containing a comprehensive set of urban resources. That is the studio’s design perspective; it does not establish that the boat has every utility or treatment system of a fixed home.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.How it compares with other solar-houseboat examples
Published figures for other boats can offer context, but they should not be mistaken for Fàng Sōng’s specifications or treated as a head-to-head test.
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| Example | Published figures | What the source says |
|---|---|---|
| Fàng Sōng, Crossboundaries project | 62 m² interior gross area; approximately 50 km on a sunny day at an average 7 km/h; solar self-reliance usually March through November, with winter shore-power supplementation | Architectural project description; no array wattage, battery capacity or independent range test stated. Crossboundaries |
| HB1, Salmo Craft | 3.4 kW solar array, 35 kWh battery pack, two 8.4 kW motors and a stated cruising speed of 4 knots | Manufacturer-published specifications for a different model. Salmo Craft also lists a propane-powered backup DC generator and onboard water and waste treatment systems. These specifications do not establish Fàng Sōng’s equipment or performance. Salmo Craft |
| Afterglow, Jonathan Sri’s houseboat in Brisbane | 900 W solar array | One household’s personal account describes solar power for a fridge, lights, radio, fan, phones and laptops, alongside rainwater collection and a composting toilet. These are not details about Fàng Sōng. Jonathan Sri |
These examples illustrate why useful comparisons need more than a range or panel figure. Readers evaluating a boat should look for published array and usable-storage capacity, propulsion power, cruising speed and the conditions behind any range claim. Season, shore-power requirements, water and waste systems, heating and cooking fuel, interior area and occupancy also matter. The available descriptions do not provide equivalent measurements across these boats, so they do not support ranking one against another.
What off-grid living still depends on
In his account of Afterglow, Sri notes that living off-grid still depends on wider supply chains and local environmental conditions. He also points to routine maintenance and exposure to severe storms and floods. This is one household’s experience, not a universal assessment and not a report about Fàng Sōng, but it is a useful reminder that onboard solar generation does not remove practical dependencies.
For Fàng Sōng, the clearest published limitation is seasonal: Crossboundaries says winter shore power supplements solar generation. The studio’s account does not provide a published cost, independent performance study or complete technical specification, so it cannot establish affordability or year-round off-grid capability.
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