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The promo video has a perfectly flat body of water. I'd be interested to know what impact waves have on a hydrofoil.
by zknill 3y ago
The promo video has a perfectly flat body of water. I'd be interested to know what impact waves have on a hydrofoil.
- Phenomenit 3y agoThere is another video on their channel that shows the technology in rougher weather and sea, seems to work fine.
- roflyear 3y agoWhich video? None of the videos I see show in rough conditions - the worst is probably "better than average" from spending time on the ocean.
- Phenomenit 3y agoThis one: https://www.youtube.com/watch?v=2i2Zf9WVlNY https://www.youtube.com/watch?v=2i2Zf9WVlNY
- 0xNotMyAccount 3y agoAll 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.
- Tempest1981 3y agoCool, definitely a smoother ride than the adjacent boat.
- RationalDino 3y agoThat 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.
- jdmoreira 3y agoThis 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.
- RationalDino 3y agoYes. 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.
- HALtheWise 3y agoI don't think the primary target for these boats is the ocean, they're mostly designed to operate on lakes, bays, rivers, etc
- travoc 3y ago...so places where 5 knot speed limits are often enforced to prevent wakes.
- SamBam 3y agoSince they barely produce wakes when they are hydrofoiling, these rules can probably be changed.
- nine_k 3y agoBut during the transition to the hydrofoil mode and back they produce a lot of waves and wake; seen this many times firsthand.
- sorenjan 3y agoThey have been given permission to drive at 12 knots because they produce much smaller wakes. https://www.hamnen.se/varldens-snabbaste-elfartyg-far-kora-fort-i-lagfartsomraden/ https://www.hamnen.se/varldens-snabbaste-elfartyg-far-kora-f...
- HALtheWise 3y agoCandela 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-faster-than-cars-and-subway/ https://candela.com/candela-p-12-enables-public-transport-fa...
- roflyear 3y agoWhy 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 https://www.youtube.com/watch?v=PebbX8uzyPI
- wood_spirit 3y agoThere 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.
- roflyear 3y agoCan you link? I don't see anything that is more than "average" waves for the sea.
- Sayrus 3y agoI think the video wood_spirit is referencing to is https://www.youtube.com/watch?v=2i2Zf9WVlNY 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.
- roflyear 3y agoAlso totally different boat eh. Those waves are probably a little bigger than they look, but yes, definitely "better than average" I would say.
- wood_spirit 3y agoA 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.
- helsinkiandrew 3y agoVideo of one of their smaller "speedboats": https://www.youtube.com/watch?v=2i2Zf9WVlNY 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/ https://candela.com/faq/
- sergioisidoro 3y agoThat video has the title "extreme weather". That's a very liberal use of the word "extreme"
- mbrameld 3y agoIt's extreme relative to the operating capabilities of the hydrofoil.
- silvestrov 3y agoNow try the North Sea on a windy day: https://www.youtube.com/watch?v=TYzIWngs_T8 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.
- Gud 3y agoI doubt these small taxis are designed for the North Sea though.
- chrisco255 3y agoNo these are mostly meant for rivers and intercoastal waterways. They're not going to be used for intercontinental travel.
- tyfon 3y agoThey would be perfect for the public boat transportation system in the Oslo fjord between the islands there.
- tauntz 3y agoHydrofoiling 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-b8f1-11eb-98b6-49bcde121acf.jpg https://images.delfi.ee/media-api-image-cropper/v1/02cc3aa0-...
- nine_k 3y agoThe Greek apparently still operate hydrofoil boats between islands on Mediterranean sea. Sea, not river.
- riffraff 3y agoSame in Italy. Both sea and lakes.
- KWxIUElW8Xt0tD9 3y agoI recall a hydrofoil on Lake Garda -- obviously lots of power required -- it was much louder than the normal ferries on that lake.
- nine_k 3y agoSome 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.
- ge96 3y agojet foil in Japan https://www.youtube.com/watch?v=e_lKISuF5Y4 https://www.youtube.com/watch?v=e_lKISuF5Y4 edit: shorter video
- tim333 3y agoI think that's a Boeing 929 Jetfoil. They've been going since 1974 https://en.wikipedia.org/wiki/Boeing_929_Jetfoil https://en.wikipedia.org/wiki/Boeing_929_Jetfoil
- HumblyTossed 3y agoWouldn'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.
- acyou 3y agoHere'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=imaxguy 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.
- eschneider 3y agoAbsolutely 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.
- acyou 3y agoInteresting, 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.
- stcredzero 3y agoI 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.
- btbuildem 3y agoI 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.
- devindotcom 3y agothey 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.
- deleted 3y ago[deleted]
- yencabulator 3y agoIt'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.
- aidenn0 3y agoThe 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.
- chrisweekly 3y agoIn 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.
- smileysteve 3y agoI 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.
- jasonwatkinspdx 3y agoDepends 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.
- mlhpdx 3y agoFoiling 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.
- briffle 3y agoNavier 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.youtube.com/watch?v=HQbT4pr5ylE&t=6s https://www.navierboat.com/ https://www.navierboat.com/
- spanktheuser 3y agoI 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.
- Candelaboat 3y agoMikael 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 https://www.youtube.com/watch?v=xIp9OkMzZkM
- mstade 3y agoI 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.