Solar-Assisted Power Catamarans: How It Works
Fast facts:
- The OceanWalker S60's solar option is a 22-panel, 9kW array feeding the boat's house battery bank alongside its 32kW generator.
- Standard propulsion is 2 × Volvo Penta D6-440 (880 hp combined); LOA is 18.87 m (60 ft), beam 8.38 m (27'6").
- Price is €3.2M with all options, including solar, included; the S60 is available now as a Mediterranean demonstrator.
- Solar assists the S60's generator rather than replacing it — a solar powered catamaran still needs a genset for AC-heavy days and passages, just for fewer hours.
- Most buyers researching a solar powered catamaran want proof it cuts running costs, not just a panel count.
What the S60's solar option actually is
The OceanWalker S60's solar option is a 22-panel array producing 9 kW at peak output, mounted across the hardtop and flybridge roof where it captures unobstructed sun for most of the day at anchor. It's wired through a dedicated charge controller into the S60's house battery bank — the same bank that runs the fridge, freezer, saloon and cabin lighting, navigation electronics, and, when the generator or shore power isn't running, the air conditioning compressors. This is the standard architecture behind any solar powered catamaran in this size bracket: the panels don't power anything directly, they top up the battery bank continuously through daylight hours, and the boat's systems keep drawing from that bank exactly as they always would.
Marine solar technology has moved on considerably over the past few seasons. The panels specified on the S60 are higher-efficiency units than what was typical even three or four years ago, meaning a 22-panel array now delivers meaningfully more usable power for the same deck footprint than an equivalent array would have in the early 2020s — a genuinely useful shift on a boat where flybridge and hardtop space is finite and has to be shared with antennas, radar and tender-handling gear. For a buyer comparing a solar powered catamaran against a boat with no solar option at all, the practical difference isn't a badge on a spec sheet: it's whether the battery bank is already 60–80% recovered by the time the sun goes down, or starting the evening from empty. In short, a solar powered catamaran is judged by how much daily draw the array absorbs, not by panel count alone.
How the array powers house systems, hour by hour
Think about a typical day at anchor rather than a spec sheet. Early morning, the fridge and freezer cycle on and off, cabin lighting is minimal, and nav electronics are mostly idle — a light load the 9 kW array comfortably outpaces within an hour or two of good sun, even before the batteries have had a full day to recover. Through the middle of the day, when the sun is highest and the array is producing closest to peak, a solar powered catamaran like the S60 is doing its most useful work: covering the fridge/freezer cycle outright, running lighting and entertainment systems, and putting genuine charge back into the house bank rather than just offsetting draw. That daytime absorption is the entire point of choosing a solar powered catamaran over a generator-only boat.
The variable is air conditioning. AC compressors are by a wide margin the largest single load on any 60 ft catamaran at anchor in the Mediterranean summer, and a 9 kW array — even a well-positioned one — isn't sized to run full-boat AC indefinitely on solar alone. What it does instead is reduce how much of that AC load has to come from the generator: with the battery bank already substantially topped up from a day of sun, the generator doesn't need to run as long, or as often, to keep AC comfortable overnight. On a cloudier day, or with heavier AC use, the array simply contributes less and the generator picks up more of the load — which is exactly why solar on a boat like the S60 is described as an assist system, not a replacement for the genset.
How much generator-free anchoring the array realistically buys
Published generator fuel-consumption data for a 30 kW-class marine genset — close to the S60's own 32 kW unit — shows roughly 1.3 US gallons (about 4.9 litres) per hour at light load, rising to around 1.8–2.4 gallons (6.8–9 litres) per hour as the load climbs toward AC-heavy running. Those numbers matter because they translate directly into what solar buys an owner in practical terms: fewer hours the generator needs to run to keep the boat comfortable overnight.
In shoulder-season Mediterranean cruising — spring and autumn, when AC demand is light or off altogether — a solar powered catamaran carrying the S60's 22-panel array can realistically go a full night at anchor without running the generator at all, provided the battery bank started the evening well-charged from a sunny day. In peak summer, with AC cycling through the night, solar won't eliminate generator use, but it can meaningfully cut it — trimming what might otherwise be three or four hours of overnight generator running down to one or two, because the battery bank isn't starting from as deep a discharge. These are realistic ranges, not guarantees: cloud cover, an anchorage in the shade of a headland, and how hard the AC is worked all move the number in either direction. Owners considering a solar powered catamaran should think of it as buying back hours of quiet, not switching the generator off entirely.
The real cost comparison: fuel, maintenance and an honest payback
This is the section buyers evaluating a solar powered catamaran care about most: real numbers, not marketing claims. It's worth doing the maths honestly rather than promising a headline payback figure that can't be sourced. Marina diesel across the Mediterranean typically runs somewhere around €1.60–€1.80 per litre once the usual marina premium is factored in — call it €1.70/litre as a working assumption. Using the fuel-consumption figures above, a generator running for AC-heavy anchor loads might burn in the region of 6–9 litres per hour; cut two hours of overnight generator running per night through solar assist, and that's roughly 12–18 litres, or somewhere around €20–€30, saved per night.
Over a full Mediterranean cruising or charter season — say 18–20 weeks, or somewhere around 130–140 nights at anchor — that range of nightly saving adds up to somewhere in the region of €2,500–€4,000 in fuel alone, assuming solar meaningfully cuts generator hours on most, not all, of those nights. That's a working estimate built from published fuel-consumption data and a stated diesel-price assumption, not an invented ROI figure — and it's before counting the maintenance side: marine gensets are typically serviced on running-hour intervals, commonly every 250–500 hours, so fewer hours run each season means fewer service visits and less wear on starters and impellers. Set against the upfront cost of specifying solar, this isn't an overnight payback — it's a multi-season case that a buyer evaluating a solar powered catamaran should weigh over the boat's ownership period, not against a single summer.
Quiet mornings: why comfort matters as much as cost
Fuel savings are real, but for a lot of S60 owners they're not actually the main reason to specify solar. Anyone who has anchored near a boat running its generator at 6am — or been that boat — knows what a difference a quiet cockpit makes to the first coffee of the day. For owners who live aboard part of the season, or who charter the S60 out, that quiet matters commercially as well as personally: charter guests notice generator noise and vibration through the hull far more than they notice a spec sheet, and reviews reflect it.
A solar powered catamaran that can sit at anchor overnight on stored solar charge, generator off, isn't just a fuel-cost story — it's a genuinely different experience of owning the boat. Mornings without generator hum mean real silence for guests still asleep in the forward cabins, no diesel smell drifting back from the exhaust, and less vibration through the hulls at a time of day most owners specifically bought a catamaran's stability to enjoy. It's a legitimate part of the buying decision, not a soft add-on, and it's one of the reasons solar has moved from a niche option to one of the more commonly specified extras on boats in the S60's class. That's the comfort case for a solar powered catamaran in one line: less engine drone, more actual peace.
Seeing the solar option for yourself
The S60's solar array isn't a paper option — it's fitted and running on the current Mediterranean demonstrator, priced at €3.2M with all options, including solar, included. European Yacht Brokers can walk a prospective buyer through exactly how the system performs as part of the standard viewing and private viewing process: checking the battery bank's state of charge, seeing the array's live output on a sunny day, and discussing realistic generator-hour savings based on how the buyer actually intends to use the boat — full-time liveaboard, charter, or occasional Mediterranean cruising.
For buyers specifying a new hull rather than buying the demonstrator, the 22-panel array is available as an order option, the same as it is on the boat currently available to view. Anyone comparing a solar powered catamaran against a non-solar equivalent is better served by seeing both side by side than by reading spec sheets — every solar powered catamaran option Revolution lists can be viewed with the array running, not just described on paper — full details on the model itself are on the OceanWalker S60 page, and the current demonstrator is available to view alongside other listings at Cannes. For how the solar array also extends comfortable range on longer passages, see the power catamaran range and passage-making guide; for the wider set of ownership guides covering the S60 and its options, see the Guides hub.
Useful links
For readers researching marine solar and the S60's propulsion further, two independent sources are worth checking directly: Volvo Penta's own D6 engine specification page for the standard propulsion fitted to the S60, and Victron Energy's marine solar and battery systems overview for the wider technology context behind a solar powered catamaran's house-power setup.
Solar-Assisted Power Catamarans FAQ
Does solar fully replace the generator on the OceanWalker S60?
No — it's an assist system, not a replacement. The 22-panel, 9kW array reduces how many hours the 32kW generator needs to run, sometimes eliminating overnight generator use entirely in shoulder season, but AC-heavy summer nights still draw on the genset.
Does adding solar affect the S60's resale value?
Solar is increasingly expected rather than exotic on boats in this class, and a documented, working array with genuine generator-hour savings is a reasonable selling point to a future buyer evaluating a solar powered catamaran of their own — though, as with any option, actual resale impact depends on the wider market at the time of sale.
Does solar work well in the Mediterranean's climate?
Yes — the Mediterranean's long, high-sun cruising season is close to ideal for marine solar, with more consistent daily output than northern-latitude cruising grounds see for most of the year.
Is the solar system hard to maintain?
No — panels have no moving parts, and maintenance is largely limited to keeping the array clean and periodically checking the charge controller and battery bank, tasks any yard servicing the boat's other systems already carries out.
Can I see the solar array running in person before buying?
Yes — it's fitted to the current Mediterranean demonstrator; book a private viewing and European Yacht Brokers can show the system's live output and battery state of charge as part of a standard private viewing.
See the S60's solar option running, in person
Book a private viewing of the Mediterranean demonstrator and watch the 22-panel array charge the house bank in real time.
Book a Private Viewing