Candela P-12 taking off – Electric hydrofoiling passenger vessel [video] | Hacker News Reader

Candela P-12 taking off – Electric hydrofoiling passenger vessel [video]

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330 pointsJoachimS176 comments

I’m wondering how they deal with unseen logs and kelp patches which one will invariably encounter. As a frequent kitefoiler these two things can ruin your day. Not only can debris damage your mast and foil but kelp and seaweed tend to aggregate and pretty quickly one can have tens of pounds wrapped around ones foil resulting compounding drag. Even with the momentum of the vessel I don’t see how it will be able to get on foil again after encountering floating patches of kelp.

Seems like real code :) https://imgur.com/a/OTNsf5X (spotted from the video - looks like .cpp, Visual Studio Code as IDE)

They are using FreeRTOS, communicating over a CAN bus using CANopen. Looks like this is a shutdown routine, shutting down various devices. They seem to have separate tasks for propulsion control and GPS.

Pretty standard fare for a vehicle controller.

The promo video has a perfectly flat body of water. I'd be interested to know what impact waves have on a hydrofoil.

There is another video on their channel that shows the technology in rougher weather and sea, seems to work fine.

Which video? None of the videos I see show in rough conditions - the worst is probably "better than average" from spending time on the ocean.

This one:

https://www.youtube.com/watch?v=2i2Zf9WVlNY

All vessels have limits on the sea state they can handle, particularly small vessels. Very large vessels can generally handle much more. You can see how much more the traditional small patrol vessel is bouncing out there, my spine hurts just watching. I could see this being used for pilot vessels and harbor patrol craft, for sure.

Cool, definitely a smoother ride than the adjacent boat.

That isn't rough.

According to another comment, the Candela can handle waves of up to 1.2 meters. But about half of waves in the open ocean are 2+ meters. So this boat can't handle a normal ocean sea.

This is Sweden. I've lived in the east coast of Sweden for 10 years, never seen a wave and there is water everywhere.

Now I'm from Portugal, so… no comparison really.

Yes. The east coast of Sweden is the Baltic Sea, which is not an open ocean. This boat may be perfectly usable there. But that's still not a rough sea. Other than temperature, that is water that I'd be perfectly comfortable swimming in.

I don't think the primary target for these boats is the ocean, they're mostly designed to operate on lakes, bays, rivers, etc

...so places where 5 knot speed limits are often enforced to prevent wakes.

Since they barely produce wakes when they are hydrofoiling, these rules can probably be changed.

But during the transition to the hydrofoil mode and back they produce a lot of waves and wake; seen this many times firsthand.

They have been given permission to drive at 12 knots because they produce much smaller wakes.

https://www.hamnen.se/varldens-snabbaste-elfartyg-far-kora-f...

Candela has been granted a waiver for the 12 knot speed limit in Stockholm, presumably because they make way less wake. Places like the San Francisco Bay are also clear examples of not-the-ocean but no-speed-limits.

https://candela.com/candela-p-12-enables-public-transport-fa...

Why do you need a ferry for a small lake? Anything you'd need a ferry for won't be much distinguishable from an ocean. https://www.youtube.com/watch?v=PebbX8uzyPI

The Great Lakes are not that choppy on average except during storms. But the primary use case would be along intercoastal waterways and rivers, which are also very calm except during storms.

I dunno, where there is boat traffic there will be chop as well. So it's intercoastal, low traffic areas.

> Why do you need a ferry for a small lake?

E.g.:

* https://en.wikipedia.org/wiki/Toronto_Island_ferries

* https://streetsoftoronto.com/guide-to-the-toronto-islands-fe...

How about Puget Sound (Seattle, Tacoma, Olympia...), where there are ferries all over. Several routes have "foot ferries" (no cars) offering rides with added speed to get the commuters to home or work across several miles of semi-open waters. Only rarely are waves a serious factor, and I don't know if that's even serious enough to affect this watercraft. Just one example of where this could really be useful and profitable. I can think of others.. Chesapeake Bay, Lake Champlain, Great Lakes...

What about between OAK and SFO terminals inside security, so that connecting flights (or East Bay passengers boarding and returning) could transfer to & from international gates at SFO?

With Google Maps I found a ferry on the Swedish lake Hjälmaren, between Vinön and Hampetorp.

https://sv-m-wikipedia-org.translate.goog/wiki/Vin%C3%B6lede... says the route is 5km long and takes about 16 minutes.

Wikipedia says the lake is 483 km², while Lake Champlain is about 3x bigger at 1,331 km².

From Google Street View it seems the mainland is visible for nearly every direction.

Oh! I found another ferry, a car ferry from "Boheden, 956 93" to "Sandudden, 956 93 Överkalix", according to Google Maps. The lake Djupträsket is 8.68km² and the ferry is a few hundred meters.

And one between Sund and Jarenleden, on the lake Stora Le, 131 km² but it's narrow and the ferry is only about 600m.

Sweden has a LOT of lakes, and most of them are narrow. I assume they were made by glaciers? I found those two ferries by looking for two roads ending on opposite sides of a lake.

The Stockholm area looks like this:

https://www.google.com/maps/@59.3284101,18.0369884,11.71z?au...

There are plenty of places where the water route is much, much, much faster than the land route, and there are plenty of islands that are only accessible by boat.

As you obviously have never been to Stockholm, feel free to pay us a visit. Its really nice in the summer! This is the ferry map for the archipelago: https://waxholmsbolaget.se/globalassets/kartor/hela-skargard... Note though that that doesn't include the line the P-12 will be in service on from next year as that is line 89 run by SL: https://sl.se/globalassets/linje-89.pdf

https://www.hamburg.com/visitors/hamburg-by/13965006/ferry/

There are plenty of places with large expanses of flat water where a fast electric ferry would be useful.

Yes, you get surface chop, but this craft is designed to keep foiling in up to 1.2 metres of chop. That’s heaps for many bays, estuaries, lakes etc.

There are lots of videos on YouTube of the smaller C8 in choppy seas and crossing the wakes of other boats.

I happened to see one for real gliding over some waves big enough to give me a bumpy ride in a conventional motorboat.

So they do better than a conventional motorboat in the kind of normal rough sea.

There must be some wave height that starts to give it problems, but it’s up past where normal little motorboats become hampered too.

Can you link? I don't see anything that is more than "average" waves for the sea.

I think the video wood_spirit is referencing to is https://www.youtube.com/watch?v=2i2Zf9WVlNY

It's not extreme weather and the waves don't reach the length of the foil itself. I'm curious as well as to what happens on rough seas.

Also totally different boat eh. Those waves are probably a little bigger than they look, but yes, definitely "better than average" I would say.

A quick search for “candela c8 rough” finds some?

Boy do I want one. For those calm days though. The quietness is another big draw. I have a 4stroke and it’s so peace destroying.

Video of one of their smaller "speedboats": https://www.youtube.com/watch?v=2i2Zf9WVlNY

I guess they can operate in waves that don't reach the hull? At least sideways

EDIT: Their FAQ says the speedboat can handle 1.2M high waves: A Candela generally outperforms regular leisure boats in rough weather. The maximum wave height when foiling is approximately 1.2 meters from wave peak to valley.

https://candela.com/faq/

That video has the title "extreme weather". That's a very liberal use of the word "extreme"

It's extreme relative to the operating capabilities of the hydrofoil.

Now try the North Sea on a windy day: https://www.youtube.com/watch?v=TYzIWngs_T8

Watch the helicopter coming in to land 30 seconds into the movie. It lands at the end.

I doubt these small taxis are designed for the North Sea though.

No these are mostly meant for rivers and intercoastal waterways. They're not going to be used for intercontinental travel.

They would be perfect for the public boat transportation system in the Oslo fjord between the islands there.

Mikael at Candela here. Norway is indeed a target market for us!

Just in case anyone was ever wondering why the conditions of a SpaceX launch (specifically for the water landings), but also any launch with an at sea recovery zone can prevent a launch from occurring even if the weather is sunny at the launch site.

Wow that helicopter must be super light weight for the blade to rotate so slowly near the end. :-)

Fantastic example of stroboscopic effects in video.

And? It's a ferry designed to operate, like most ferries, in littoral waters. Harbors, bays, rivers, channels, and ocean areas close to shores. Not North Atlantic bluewater conditions.

This has as much relevancy as "nerrrrrr, dumb plane, why did they build it if it can't fly from NYC to Australia" while looking at a picture of a Dash-80, a regional commuter plane.

Now try Las Vegas. I can beat it on a bicycle by myself over any distance under 200 miles and if you have to return to the Luxor pyramid, I could beat it myself over any distance.

That's a well know problem for all of us that want to surf around Stockholm: the baltic sea us just too calm. You can go to Torö and hope for rhe best but in reality even with good wind, all you can do is wing or SUP foil, not even enough to try prone foiling...

(My comment may sound sarcastic but I am serious: the baltic sea has always seen other types of boats, both for leasure and commercial)

They have sensors that detects waves and adjusts the hydrofoils to avoid crashing into the water.

If one would like to use hype words I guess one could call them AI-driven hydrofoils or something

Control is the word you are looking for.

It is a _control_ system that takes sensor _inputs_ and _outputs_ hydrofoil tilt actuation.

It maybe controlled by undergraduate Control Theory or some secret sauce predictive model but making a claim in either direction is speculation.

Mikael at Candela here. Our C-8 can foil in wave heights of around 1.2m, which are pretty big waves for a 27-foot leisure boat. The P-12 is designed for much bigger waves, and can foil in 2 meter high waves, meaning it will be able to cover rough weather in archipelagos and littoral waters. The catamaran hull is also efficient at slower speeds up to 10 knots, if the weather would not permit foiling.

Hydrofoiling boats have been in commercial use for quite some time. I've taken one[1] between Estonia and Finland a couple of times but these are sadly not operating anymore.

1. https://images.delfi.ee/media-api-image-cropper/v1/02cc3aa0-...

The Greek apparently still operate hydrofoil boats between islands on Mediterranean sea. Sea, not river.

Same in Italy. Both sea and lakes.

I recall a hydrofoil on Lake Garda -- obviously lots of power required -- it was much louder than the normal ferries on that lake.

Some hydrofoil ships are powered by turbines, which produce a high-pitch whine, much more noticeable at a distance than the low-frequency rumbling of a diesel.

jet foil in Japan https://www.youtube.com/watch?v=e_lKISuF5Y4

edit: shorter video

I think that's a Boeing 929 Jetfoil. They've been going since 1974 https://en.wikipedia.org/wiki/Boeing_929_Jetfoil

What are the economics of hydrofoils like? I recently watched a YouTube video covering the rise and fall of hovercraft ferries. Basically, the lower reliability of hovercraft eventually overwhelmed the utility of faster transit times. Is it the same for hydrofoil ferries?

I remember reading articles about the Silja Line ferries needing repairs all the time. But that might have been an issue with the specific models and not an indication of hydrofoil reliability in general.

They must be much more efficient than both boats and hovercraft - they don't need to keep the air cushion, and they don't need to push their full tonnage away from their path - lift losses excepted, they must be equivalent to much smaller boats.

I would expect to see more of these as recreational vehicles, as they must be much cheaper to operate and, with recreational boats having a much lower duty cycle than, say, BEVs, solar recharging becomes attainable, as long as you keep the boat docked or anchored and charging for much longer than you use its propulsion.

I saw a single person standup foil on a local lake. They look unreal, almost unbelievable in operation. Like someone is flying over the lake. Search for efoils on youtube

This does sound approachable. From my experience, people with lake front property and docks with boat "houses" are clear from any obstruction of direct sun. Line the roof of said boat "house" with solar, and in the typical weekender/vacationer use of a boat, seems pretty managable. However, when the sun is up to be charging is typically the time of the boat's use so it won't be on the charger. Use the solar to charge a powerwall type of solution, and then charge the boat at night?

Solar panels could be on the boat itself, but I am assuming solar won't be able to do much recharging while the engine is in use anyway. OTOH, very few boats are used, or moved, every day.

I imagine a boat would have a hefty battery pack anyway, to power a stove, fridge, air conditioning, plus essential bridge equipment.

I think we're talking different sized boat on a lake. Do house boats typically power from battery or from a generator? I have no familiarity with those.

Most houseboats are barges with no propulsion. They use shore power but often have a backup generator. Having some solar or a small wind turbine is relatively common too.

Yes. I was thinking "river boat with limited propulsion that is moved when the owner wants a change of scenery".

Boat houses are extremely heavy, for obvious reasons. Hydrofoil requires light construction, so these two are not compatible (plus it only works at speeds you would not want to have a house moving at).

A Boeing 929 Jetfoil with ~450km range, ~300 passengers, 2x Rolls-Royce Allison turboshafts is often quoted to be ~$60M. Tickets are $35-$120. Many routes operating it has been seeking government subsidization to build replacements as hulls near ends of life; so far, only one 929-117 has been built since the turn of the century.

IOW, not a lucrative business on its own, makes _some_ sense as a subsidized public transportation.

Hi there, Mikael at Candela here. Since the P-12 uses 80% less energy than a conventional vessel, the cost of operating it is far less than diesel vessels- overall around 50% percent lower including service, energy, salaries etc. This makes electrification desirable for operators for the first time. Usually, conventional (non-foiling) electric vessels are more costly to purchase than diesel vessels, and more costly to operate too, as they require MW charging infrastructure on land. The P-12 uses a DC style charger of up to 175 kW, which is pretty affordable to install.

I talked to the skipper of one. He said the boats (Linda Line) had been in service in the Black Sea.

On the Thames: https://www.londonreconnections.com/2020/soviet-fleet-on-the...

I took one from Tangier to Gibraltar, in the 1970s (Might even have been the 1960s).

Wouldn't / Shouldn't they slow down out of hydrofoil speed when they enter rough seas? I would imagine that would be the prudent thing to do.

Here's old footage of the foilborne Canadian Navy hydrofoil HMCS Bras D'Or from the 1970s, with some rough sea action right at the start of the video. Doesn't look like a smooth ride, and must be a huge stress on the hydrofoil structure: https://www.youtube.com/watch?v=XVYSUWEi-WQ&ab_channel=imaxg...

I think that as a general rule, longer vessels tend to be more seaworthy, they don't get swallowed by waves.

Absolutely not true. Long vessels have different problems with waves, like having the bow AND stern lifted by waves at the same time, so you have a whole different set of failure modes.

Interesting, but I think many ocean-going vessels tend to be fairly long for good reason, with the bigger, longer ones also being faster and more capable in rough seas.

Offshore commercial fishing boats are an example of shorter ocean-going boats. I think they would normally prefer to avoid storm seas if possible. They have to head up and turn into the waves, they can't take them sideways.

One example of when people thought that a big, long boat would be more seaworthy, was the Titanic, which sank in 1912 after hitting an iceberg. But it wasn't the waves that did it.

I think big, long and strong boats are pretty great in rough seas. If I was crossing the Atlantic, I think I'd rather be in a bigger boat, provided that it doesn't break up or develop any leaks.

I think I'd rather be in a bigger boat, provided that it doesn't break up

This is a very high structural demand. Torpedoes work best, when they can effectively "lift" the keel, breaking the back of the ship. (Not exactly, but kind of, IIRC.) Very high sea swells apparently do the same thing! When there's far less buoyancy supporting one end of the ship than the other, the entire ship has to act as a cantilever. At the size of large ships, the square-cube law dominates, and the ship is far more fragile at that scale than a model boat would be. Even steel structures at that scale are flex-y.

I imagine one of the challenges would be getting up to foiling speed in rough waters. From the videos I've seen, once the hull of a foil boat is out of the water, the ride is much less affected by waves.

they take off at around 7-8 knots, so as long as you can get up to that you're good. the motors and wing stay well below the water, the candelas do wave detection as well IIRC.

It's intended for use in coastal waters in the Baltic Sea, around lots of islands and behind the Danish straits that significantly tame incoming winds & waves:

> P-12 [...] will halve commuting times in Stockholm from 2024.

In the waves hydrofoils can handle, they're more comfortable than traditional boats -- the waves don't move the boat around as much.

The deeper the lifting surface the larger the waves can be. You need the waves to not have too much of an impact at their peak while the foil still being underwater at the trough. Unless the foils can extend and rectract[1], the depth of the lifting surface impacts minimum draft of the ship as well.

1: Or fold, though with folding foils, you need to transition from foiling to floating where the water is deep enough, then float into the shallower water.

In general, hydrofoils provide a smooth ride as the vessel is lifted out of the chop. But in more extreme conditions, the hull can nosedive or otherwise slam back down into the water, at which point it's lost its momentum required to stay in foiling mode.

I foil and efoil as a hobby; Once on foil, surface waves have no impact as long as you keep the foils in the water -- this means observing and adjusting attitude. If you do it well, you can maintain full speed and only feel the attitude changes (no bumps). Though, if it is very windy and wavy on the ocean/lake it is more difficult to develop foiling speed to take off.

The reason why Candela is pioneering sub surface foils now is because it takes a reasonable amount of sensors and computation to avoid the foil breaching.

For the most part, you wouldn't want to take a sub surface foiling vessel flying out in a storm with significant swells, but that's not what most boating is anyway.

Depends on the height of the waves relative to the height the foiling boat flies at. There's a reason those America's Cup boats and the big ocean going trimarans that use foils have quite different designs.

The biggest issue is that if the foiling fails the boat has a tendency to bury the bow quite violently. This killed an AC sailor a decade or so ago.

Foils make sense for inland waterways but making them work for the ocean proper is considerably more difficult.

I'm no naval architect but this boat is awfully narrow in beam which is probably its biggest limitation.

Foiling sailboats deal with pretty substantial wave action, including open ocean storms. It’s all in the design.

What’s really shocking to me is how slow this ferry is compared with those foiling sailboats which can reach upwards of 90 km/h.

Navier boats in the bay area has a very high end luxury electric hydrofoiling boat, and this guy took a tour in much rougher waves, with a wife that is easily sea sick. they did fine, since you are no longer riding up and down the waves, more through them. Also, they use much, much less power once they are up on the hydrofoil, since they have much less resistance, just takes a bit to get up to speed first (which electric motors are great for)

https://www.youtube.com/watch?v=HQbT4pr5ylE&t=6s

https://www.navierboat.com/

I have taken a several hour hydrofoil ride in the Mediterranean in moderate swells.

The ride is deeply nauseating as the foils are positioned towards the outside corners and (on this 200+ passenger craft) catch the swells independently. The result a ride with similar pitch and roll as a traditionally-hulled ferry, with far more yaw and far less periodicity.

Mikael at Candela, the hydrofoil maker, here. Our P-12 uses submerged hydrofoils and emplys a digital Flight controller, which stabilizes the craft by adjusting the angle of attack of the foils 100 times per second. So the pitching and heaving you found nauseating in the old Soviet Raketa and Kometa hydrofoils don't exist in P-12 - it's smooth sailing even in. chippy weather. Watch this video: https://www.youtube.com/watch?v=xIp9OkMzZkM

I can speak to this a bit, having piloted a Candela (the speed boat version, I forget the number) on the Swedish west coast where seas can get notoriously choppy seemingly out of nowhere. This is a couple of years ago though so maybe they've improved things since.

The impact of any waves higher than maybe a meter is likely to make the software take you in for a rather rude landing, and quick stop.

It's unlike any boat of that size I've piloted, it was very heavy and it never felt like you were totally in control, with some small but quite noticeable latency between input and action. Felt more like piloting a larger ship than a small speed boat.

The fact that it felt like you were at the mercy of the controlling software meant it became a very anxious ride as soon as you ran into a bit of choppy waters.

When flying it was a very nice ride, but when you're not you have to go very slow or you quickly run out of battery. It was not particularly pleasant doing 3-4 knots in choppy waters, even if it did seem rather stable presumably due to the wide base, low height and deep rudders (foils).

Fine boat in calm seas for sure, but I wouldn't use it for anything else. Should do fine in fair weather in central Stockholm though.

How robust are these to random floating logs? They’re quite common here in the Salish Sea and have been cited as the reason that the Boeing hydrofoil project never really took off.

Hitting debris or the bottom while on foils is NOT recommended and can be catastrophic to the boat and its passengers.

Hydrofoils haven't taken off because of the above and, primarily, the high operation, maintenance, and build costs. Historically, these just have not been more economical than their traditional counterparts.

Being that this particular company is not focused on those parts of this and are solely focused on the technology being green, my guess is they are ignoring the operation, maintenance, and build costs and hoping that they can be all hand-wavey about that part--which probably will not pay off for them.

My understanding was that, similar to a sail on a boat, you really want to be able to "trim" your foil, which is really complicated. You can have a good "average" foil but it will really be great in most conditions.

Candela foils are dynamically trimmed under computer control.

From an engineering perspective the hull would have to be strong enough to support all the weight of the vessel on the foil mounts. I imagine this is not a trivial problem to solve and the vessel would have to be purpose designed for foils, so little retrofitting may be possible on existing vessels.

I clipped a granite plinth Efoiling - your ride comes to a very abrupt halt. Thankfully the board was fine and the carbon fiber wing had just minor scuffing.

I would be concerned that the carbon fibre has been significantly weakened by the impact.

https://www.resinlibrary.com/knowledge/article/can-carbon-fi...

> Since fibre strength significantly exceeds that of the matrix (epoxy), damage usually occurs in the matrix before the fibres for laminate composites. In some instances, this is relatively easy to detect; snapped fibres protruding from the object’s surface. Yet more microscopic damage – something which can spread through the object – is harder to detect even though it can significantly reduce the mechanical properties of the composite.

I’m concerned, but it’s a hobby where the penalty for failure is getting wet.

That looks like a lot of fun, kind of like a OneWheel on water, but safer because water lands a lot softer than the hard ground does!

Weight of the boat + dynamic loads.

Great point lol it's not like the carried load will be the same all the time and I didn't even consider that :)

Well, there's cargo, and there's also waves, wind, and whatever it might bump in to.

Boats are, in general, an unpopular way to carry passengers these days, and of those, hydrofoils have a significant share. It's debatable whereas anything ense has "taken off" if hydrofoils didn't.

There must be thousands or tens of thousands of ferries around the world, yet hydrofoil ferries are as rare as rocking horse shit, so I don't think this is correct.

I know only a couple of non-ferry scheduled passenger boats (no car deck) and half of these are easily hydrofoils. I guess that depends on the region, though.

> the Boeing hydrofoil project never really took off.

badoom tish

Don't tell us, you're here all week? ;)

I actually rode a C-8 around Elliott Bay and asked about this since as you say there's lots of logs, or deadheads as my grandpa called them. They said it's not optimal but the logs can be detected and accounted for, and the fins are super strong to impacts from the front. Better to avoid, of course, but they said it would be OK. It just whacks them out of the way basically.

Many logs in the Salish Sea are actually enormous tree trunks complete with root systems…

My neighbor worked on those hydrofoils. He once told me the foil's spars (?) were made of titanium, which could handle (eg obliterate) sizeable logs. 10" diameter?

Edit:

Just asked neighbor. He remembers the Pegasus was rated for 18" logs. https://en.wikipedia.org/wiki/USS_Pegasus_(PHM-1)

Also, the intended top speed proved infeasible, because the foils (wings) would cavitate at high speed, reducing lift.

He also worked on Boeing 929 jetfoils.

Additional color to the story was a collision with a whale. Gruesome. Big PR mess too. So now no more hydrofoils on the Salish Sea.

would be a perfect application for sonar, wouldn't it?

Also check out https://www.navierboat.com/, a competitor in this space.

And an amazing historical progenitor:

https://www.youtube.com/watch?v=E2i3EeUnku0

https://en.wikipedia.org/wiki/USS_Plainview

Raketa was a passenger, earlier and mass-produced one.

https://en.wikipedia.org/wiki/Raketa_(hydrofoil)

> Ferries are by far the most polluting form of transportation today

Interesting

The video also says that if it didn't plane up into hydrofoil-mode, it'd need to use enough energy to push 12 tons (full weight) through water. How much does it need to push in hydro-foil mode/what kind of percentage reduction are we looking at?

It fits 30, 20, or 12 passengers depending on configuration and cost €1.7m. Which EU country is willing to buy like... 100 of these?

It can't be cheap to ride if it can only hold 30 passengers max?

There are quite a few ferries with capacity around 30 passengers in service in Sweden. Most of them burning diesel.

Ah, shows how uncultured I am for not knowing that. I'm used to 30 people all crammed into one grocery aisle pushing each other for a $6 box of sugary cereal at WalMart in America so it seemed like an "insignificant" number in terms of transportation.

(slightly kidding)

There are? Where?

In the archipelagos near Stockholm and Gothenburg, for example. There's a list of the nationally financed routes here:

https://www.trafikverket.se/resa-och-trafik/farjetrafik/

Then there are regionally and locally financed routes as well.

The ferries in that link are all road ferries. Most of them take at least 30 cars, and a lot more than 30 passengers.

Most of the archipelago ferries in Gothenburg take around 300 passengers. The smallest one I could find on Styrsöbolaget's site takes 165:

https://www.styrsobolaget.se/om-oss/fartyg/rivo

While not a ferry, it looks like Sweden has water taxis.

Looking around I found a few listed at https://visitsweden.com/about-sweden/getting-around-stockhol... , for example, https://www.battaxi.se/our-boats says the m/s Alma ("Our fast all-round boat") carries 20.

I also found https://waxholmwatertaxi.com/services/taxi-boat/?lang=en says "We offer Taxi Boat for 1-12 passengers throughout the Stockholm archipelago."

I can imagine some people might pay good money for significantly faster transport + "eco friendly".

All those are private options for tourists and natural clients for Cadela; they explicitly want to go after the Commuter ferries 80, 82, 83, 89 [0]

Each of those lines has a dozen boats to guarantee frequent service. Including the private options you listed, there are more than 100 boats in Stockholm alone, with 30 passengers or more.

Every city in Scandinavia would likely want something similar; some (Olso, Copenhagen, Helsinki) already have a boat network for commuters and tourists, but every city on that list [1] has a bus network, is around a body of water, and would interested in a non-polluting option.

I’d be surprised if they couldn’t sell thousands for public transport in the region alone — let alone lakes in the Alps, shuttles in the Mediterranean and more.

[0] https://sl.se/en/in-english/getting-around/sl-service-networ...

[1] https://en.wikipedia.org/wiki/List_of_urban_areas_in_the_Nor...

The ferry between Kyrkesund and Härön is a good example. Yes, sorry for the Swedish chef bork bork, but the picture should be enough:

https://www.vastsverige.com/sodrabohuslan/produkter/personfa...

Hydrofoil’s vary quite a bit but on average your looking at ~1/6th the drag at the same speeds. Wave height limits depends on the design, but it’s actually more comfortable in moderate surf than a normal boat and worst case they default to a normal boat.

As to the economics, there’s a long tail of these things. High speeds enable more trips per day which offsets fewer seats. Consider 3+ million people per year visit the Statue of Liberty and it’s a 2 way trip. I doubt NYC would swap, but if they did they could easily buy 10 of the things just for that one route.

The current NYC water taxi boats look plenty fast, at least for the short routes between NJ and NYC, or Manhattan and Brooklyn.

While going around the Statue of Liberty and sightseeing, high speed is not necessarily your goal %)

Pricing will also be determined by marginal maintenance and running costs; Foils significantly reduce running costs; going electric reduces running, environmental, maintenance costs.

In Vancouver there are gas stations specific for boats, I heard from an attendant at one of them that occasionally yachts stop by and fill in $50,000 worth of gas (and pay cash according to him).

Hydrofoils in theory would cut a very significant chunk of that, even if still on gas-powered boats. Given that the technology has been around for many decades, I suspect there's got to be a showstopper that prevents its adoption (vulnerable to floating logs?), and I suspect simply making them electric won't alleviate that

But we've had those for decades, no? There's a bunch of "aliscafi" doing ferries in Italy for example, both at sea and on lakes.

Similar, but quite different.

The tradition foiling ferries rely on a surface based foil which does reduce drag significantly, is not as efficient as a sub surface foil, but are easier to implement because they "ride" the surface so they don't require balancing technology.

Candela is using sub surface foils, relying on water both above and below the foil which provides significantly more lift, and immune to surface irregularities (if properly predicted).

More like the logs are vulnerable to the hydrofoils. Those vertical wings look like they can slice anything in half.

Yeah, no. This is not Starwars or samurai anime, commonly found red cedar or Doug firs go from one to many feet wide

The problem with hydrofoils is that they don't scale up very well. Practically all larger designs were always gas turbine powered to even be able to supply enough power for initial liftoff and guzzled kerosene at laughably unprofitable rates. Much like ekranoplans and hovercrafts they didn't really prove to be economical in the long run.

This smaller bus-sized version might genuinely be at the limit of what makes sense with current battery and motor tech.

Why is this? Is it because the boat mass doesn't scale linearly with surface area?

I wish I could give a good explanation, but from what I understand it's more down to fluid dynamics than usual intuition would dictate.

The resistance curve [0] has unusual peaks where resistance is highest based on wave creation and interaction with the hull length [1], which interestingly makes longer ships able to reach higher cruise speeds more efficiently (why container ships are as large as they can be), but it also increases these maximums that need to be passed, making transitioning to planing even harder. Due to these factors you'd probably need beyond 8x the engine power to plane/foil with a 2x larger ship.

[0] https://amarineblog.files.wordpress.com/2017/06/basics-ofshi...

[1] https://calconcalculator.com/wp-content/uploads/2021/12/imag...

Off the cuff, I would guess it's a power-to-weight issue. People with yachts want to fill them up with granite countertops and pools and grand pianos and who knows what else. Whereas a hydrofoil boat needs to be built with more like airplane sensibilities.

In addition to other comments, I’ve heard/read somewhere that the skill to operate is more akin to piloting an aircraft so probably a large bit of it is retraining hurdles

“We use an advanced control system that stabilizes the naturally unstable boat in just about any condition. Sensors around the perimeter of our boats measure wave height and feed this information to our Flight Controller. Height, roll and pitch data are as well. The Flight Controller is then able to adjust the position at up to 100 times per second, in order to achieve stability.”

That’s from Candela’a own webpage, and the following older article mentions:

“Many of them have worked at aerospace and technology companies such as Eurocopter, Saab Gripen, and Volvo.”

https://www.torqeedo.com/en/news-and-press/blog/blog-2020-12...

I think Candela is basically what happens when you take Swedish engineering tradition, combine it with skills attained from building advanced fighter jets and the challenge of making electric boats have a reasonable range at all.

Some added bonuses you get: Barely any wake, so you can run fast without disrupting others or the wildlife / nature.

You're so close!

It's not the issues with tech but the whims of the uber rich that prevent adoption of most innovations.

They have the money and choose the profitable things to invest in, which are nearly always the opposite of the practical things that would help the most people.

Once you begin to see the world through this lens, it all makes sense. The best place to start is to talk to old people 40, 50, 60 years old plus. They'll tell you how so much of this was solved in the 60s and 80s and even earlier, but the powers that be suppressed any innovations that reduce fossil fuel usage, the influence of finance, the profits of the arms industry, etc etc etc.

> It's not the issues with tech but the whims of the uber rich that prevent adoption of most innovations.

Please provide a list of 25 innovations who's adoption was prevented by the uber-rich.

In addition to that, also provide a list of the uber-rich who participated in each instance of preventing each of the listed innovations from being adopted.

You got to spend money to make money. Larry Ellison and Oprah spend money on real estate, the Waltons on crushing American small business, and Buffet on fleecing poor people buying mobile homes.

The EV revolution and much cheaper space access can be traced to one billionaire. Bill Gates is curing diseases. Imagine what else could be achieved if the other rich put their money toward similar projects.

So in short, innovation beyond the lab stage requires major funding and few people want to take on the risk? Sounds perfectly logical. It's human nature to value the same amount of loss far more severely than the same amount of gain.

I suppose that's why most new tech is either deployed with government funding because they don't care about burning boatloads of other people's money for some small strategic gain, or by rich lunatics with a god complex that believe they can't possibly lose despite the risks involved.

I'm not going to do that, because the list is endless. It's more useful to list the practices which the uber rich use to suppress progress by the general public:

  * Rent seeking
  * Planned obsolescence
  * Commodification
  * Underselling to break competition
  * Duopoly
  * Regulatory capture
  * Private ownership of formerly public media
  * Deregulation to avoid environmental law
  * Tax avoidance
  * Austerity to break organized labor
  * Public relations
  * Jury tampering
  * Copyright and patent abuse
  * Divide and conquer strategies like othering
  * Pork barrel projects
  * Gerrymandering
  * Nepotism and generational wealth sequestration
  * Private school vouchers to undermine public education
  * Private prisons for the prison industrial complex
  * Free trade instead of fair trade

Now I just made this list, but it's probably at least 5 times longer than this, and we don't even actually know what well-connected networks of billionaires are capable of stopping.

The problem is that Gen X people like me or older watched as most true innovations were suppressed between roughly Kennedy's assassination in the mid-1960s and 2020. That looked like fossil fuel companies preventing nearly all research into alternatives like solar, wind and lithium ion batteries. Even though we had the tech to scale those by the 80s. See Who Killed the Electric Car and similar for in-depth analysis.

What we really needed were moonshots for key tech like lithium-ion batteries, blue/white LEDs, mRNA vaccines, etc etc etc which traditionally would have come from public funding like grants to universities. Instead we got monopolization by companies like Microsoft which bought up or killed the competition. Every billionaire CEO represents perhaps 1000 individual success stories that never came to be.

Millenials and younger don't see a lot of this struggle, because they were born into a world where keystone technologies already existed. Whereas I grew up without a telephone, cable TV or the internet. Take the rose colored glasses off and the actual reality I'm speaking of is readily apparent. We're watching the same Middle East proxy wars where established power structures dominate impoverished people of color as when I was a child in the 80s. Times everything, everywhere.

You want specific people? William Randolph Hearst created cannibis prohibition to ban hemp so as not to undermine the paper mills for his newspaper empire, which led to the racist War on Drugs stealing the lives of millions of people. And also prevented cars from running on hemp oil, even though Henry Ford made cars that could run on it. Before that were fossil fuel robber barons who monopolized shipping by rail. Wealthy conservative donors to the Reagan administration suppressed AIDS research and withheld World Health Organization funds which might have saved millions of lives. Wealthy Apple investors look the other way as workers at Foxconn commit suicide as long as profits remain high, when those jobs could be fully automated and those people could be working in other fields like alternative energy. Jeff Bezos and Charlie Munger enjoy constructing windowless buildings because it's cheaper than giving employees/students a say in their quality of life. Elon Musk killed twitter under the guise of propping up free speech (that he and right-leaning financiers approve of). Billionaires in Dubai build skyscraper monuments to their own egos as thousands of people struggle to survive in the streets around them. Whole countries in the global south are little more than banana republics propping up a single billionaire dictator to supply raw materials to developed nations while their people toil and starve for a lifetime to die penniless.

I've barely scraped the tip of the iceberg as to why we don't have stuff like UBI for working on our own inventions. The most appalling thing for me is that I thought all of this was common knowledge, but it's being swept under the rug of revisionist history. I can't even believe that we are still arguing about racial and class divides that I remember we were starting to overcome by the late 90s.

Old person here - this does not resonate with my experience at all. It's been the middle class driving consumer technology since the '60s at least. The stuff that was "solved" almost always turned out to be breathless reporting hyping technologies that didn't pan out for various reasons.

> I suspect there's got to be a showstopper that prevents its adoption Weves is one of them. Hydrofoils are sensible to waives

> I suspect there's got to be a showstopper that prevents its adoption

No, it's the other way around. Diesel-powered non-computer-controlled hydrofoils weren't good enough to overthrow regular diesel-powered boats. You saved some gas, but not enough for anyone to bother.

The pressure to go green and move to electric boats means that the energy savings from going hydrofoil is suddenly extremely interesting in order to make a boat that has enough speed and range if it's gonna carry batteries. Couple that with modern sensors and computing, and their hydrofoils can do a lot more on-the-fly adjustments to further improve stability and efficiency than the older ones. And these two factors combine to make something new, and you can't say "Well, hydrofoils failed in the past, so this will fail as well".

> In Vancouver

> (vulnerable to floating logs?)

That's a very local "you" problem. The various Swedish archipelagoes have completely different conditions than the Seattle-Vancouver bay area.

Possibly also specific to the Pacific NW area, Vancouver and the surrounding islands have the largest ferry fleet in the world, yet practically all of the boats carry up to hundreds of vehicles and hundreds/thousands of passengers. Something like this would replace, optimistically, one passenger ferry (Vancouver to North Vancouver), and perhaps a handful of water taxis.

I think they're super cool (I also love moth hydrofoils), but I'm not sure they're going to replace much given the current infrastructure. Perhaps though new use cases will happen because of them

The design language was screaming Polestar then I scrolled and it turned out it was indeed using Polestar batteries.

I'm wondering if this solution lands too much in between usable options.

Long sea passages might have rougher weather which is not great for hydrofoils and might be too long for battery ranges. In short passages in inland bodies of water (with better wave conditions for hydrofoils and friendlier to battery ranges), do you have enough distance to start gliding in order to get the benefits of hydrofoil?

The high speed ferry on Lake Como uses a foil (although not as smooth as this, I’d almost say it is semi-flying perhaps) and there is more than enough distance between the ports to benefit from this Candela boat. The slow stopper ferry probably wouldn’t be a good option for this foil version (depends on acceleration time to flight I guess) though as the stops are pretty close together.

When I used to visit the island of Ischia with some regularity there used to be hydrofoils connecting it to the other island and Naples. Worked great!

this is really really old tech, these transport vehicles already exist for about 2 decades now.

Here's one I used to take very regularly.

https://www.facebook.com/watch/?v=176682457397144

Correct me if I'm wrong, but isn't that Grafana being used in the boat dashboard? At least some of the widgets seems to either be very Grafana inspired, or straight up pulled from the Grafana UI.

Probably the last place I'd expect that memory-hungry and CPU-inefficient UI to appear.

I guess your comment deliberately begs: are there any better?

> Probably the last place I'd expect that memory-hungry and CPU-inefficient UI to appear.

In a prototype with batteries large enough to heat and power a house for weeks?

The power consumption of the navigation electronics is probably not a big concern.

I would have put linux and a fullscreen electron app on those screens.

I didn't read their comment as "drains the battery", more like "slows your computer down and eventually freezes". That could still be fine if you anticipate it (and as you said, it's a prototype) and the control system (throttle, rudder) doesn't depend on it.

Its almost certainly some RTOS like QNX.

Idea: Voith Schneider Propeller with changing blade path and angle such that it has thrust phase on one side and a lift phase on the other.

Basically it would be two giant low-speed spinning hydrofoil discs. Heavy low-end torque for a direct-drive electric motor.

Always cool to see boats like this, never ceases to amaze me. Would have been interesting to know more about power, battery capacity, runtime, charging and so on.

I'm into solar and LiFePo4 batteries and for those who have little experience with batteries or maybe lead acid, it's just so unbelievable magic how well this stuff works (Or how bad lead acid really is). And what is possible.

There is a lot of engineering ahead of us, but the energy transition is in my view more of a political topic than a technical engineering challenge.

It's funny that they mention, “Our mission is to build a public transport system that is as easy and as convenient as on land,” because Stokcholm’s public transport system does include (in Summer) similar boats that are, for passengers, just as easy and convenient.

I guess the current diesel engines are not as “easy and convenient” as the electric metropolitan rail, while this would likely be…

It is a fantastic project and one that every city should buy.

These have been around for a long time. SeaWorld had a hydrofoil boat experience back in 1965. I don't think the biggest problem was the lack of electrification but more the cost, safety, and limited areas where it can operate.

What are the reasonable size limits of this tech?

Does it have positive or negative economics of scaling (does hydrofoiling on bigger electric ships get cheaper or more expensive per weight unit), or is there a ship size limit where the equation flips?

I think it's not possible to fit enough batteries by weight to scale this.

Consider the Voskhod boat which at 28 tons and 60 km/h has to have ~800kW engine. To have any useful range the battery mass and charge time would be prohibitive.

Turbodiesel and/or gas turbine work just fine though.

https://en.wikipedia.org/wiki/Voskhod_(hydrofoil)

As length increases so do the support/balancing requirements between multiple foils (front vs rear); As weight increases, lift may want to be increased to keep a low liftoff speed. As lift increases, speed and maneuverability decrease.

Navier has a more smooth looking boat. It's also from the Bay Area so you know the tech is better. https://navierboat.com

"Ferries are by far the most polluting form of transportation there is"

Wow. Is that a fact? I always thought that water transportation was the next cleanest after railroads.

I once took the hydrofoil ferry from Seattle to Victoria, BC. It was fast, but it was still a 2 1/2 hour trip. Not sure what that ferry used for propulsion, but I assume diesel.

Hydrofoils were in fashion during the 70s. Many were built 7n Norway and sold to South East Asia. As seen on James Bond. I wonder why they disappeared

Navier is also doing something similar: https://www.navierboat.com/

Navier has been very self-promotional, taking the boat and its founder on a tour all across the US selling (investors) and the community on hydrofoil-based boats.

Interesting. But what are the (un)likely failure modes?

Dude, it floats. It has the same failure mode as any other boat.

WE HAVE DONE MUCH -- BUT THERE IS MUCH -- TO BE DONE

They tested an earlier version of the Candela in the lagoon of Venice, which has quite some waves caused by other motorboats. I don't think people were impressed.

Other than a Reuter's article[1] (and some very similar articles) hyping up the testing of what looks like a pretty normal boat but with hydrofoils, I can't find anything about the reception. Is this your personal experience? Do you know why people were unimpressed?

1. https://www.reuters.com/business/autos-transportation/swedis...

I attended the boat show, tried the Candela, and heard numerous comments about it.

Don’t know the specifics but there is a lot of hostility in Venice towards boats that aren’t respectful of the canal system, where wake can cause a lot of annoyance / damage.

Can't wait to cruise up to some Central California surf lineups with all my foiling buddies in one of these

Boat == airship

Hydrofoil == airplane

What's the business case for this? Where are people are willing to pay a lot more for ferry tickets (I have to assume these boats will be more expensive, and have a much lower weight capacity)?

Sort of related, a game I play (From the Depths) has an electric hydrofoil ship called the Candela in it... except its a Battleship with armed with large lasers and missiles.

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