Foiling Electric Boat
candelaspeedboat.com
candelaspeedboat.com
The deep V profile the Candela's bow looks like it would handle dropping off the foil or hitting a big wave pretty well, and the 100 Hz foil control loop is reassuring, but my experience on little foiling sailboats would keep me cautious on one of these for a while. However, getting a boat to pop out above the waves is such an amazing feeling that I'd take a ride on one of these in a heartbeat (just maybe with a helmet!).
Some foiling sailboat crashes for reference -
I've read some on the subject, and got a book by a famous boat designer, Kotaro Horiuchi, which describes the actions of the float controllers you are talking about as well as other aspects. Foil boats have to be fairly lightweight at the moment, which is why the america's cup boats are designed the way they are.
I've also seen those e-foil surfboards but have never tried them as the price point seems absurd.
My board (and all the foils I see on surf gear) just have enhanced static stability based on some combination of dihedral, a fuselage, and a negative lift rear wing, very similar to an airplane. That's because it's down to a shift of body weight, sailing forces, etc.
It's become all the rage in the last 2-3 years with things still not quite standardized. I had to drill out my foil-approved board to get larger M10 bolts in there.
I do lurk on that forum and check out the projects people are making, there's a lot of really cool work done to 3d print propellers and other structural parts and bring the cost of manufacturing down. Between rapid prototyping and chinese BLDCs / ESCs, small electric vehicles like e-foils are actually reasonably priced to build yourself.
If you are used to it, landing unexpectedly is quite undramatic. This can happen if you foil at the lowest speed limit, or if you attempt to cross a wake or seastate that is beyond the capabilities of the boat, which is approximately 1 meter of wave height.
Water is fairly forgiving when landing unexpectedly at the speed at which the Candela Seven can operate, although you might get a bit wet.
As you mention, the deep V hull cuts waves pretty well, but we also have algorithms monitoring the position of the boat in 3D space, looking for signals that indicate a treacherous seastate or an unfavorable position of the boat. This means that we won't do the nose dives that you see in the sailing videos.
Be sure that we have landed unexpectedly quite a few times to get to where we are! :D
To sum it up, when you are accustomed to flying with the Seven and you know where the limits are in terms of wave handling, then it's no different from riding in a regular boat in choppy seas or high waves. Unruly seas require alert sailors, in all types of boats.
We're publishing a short video soon, purely focused on running through waves from large passenger ferries. Sub to our youtube to know when.
Check out our videos from the Caribbean and a comparison with an 8 meter aluminum boat in a choppy archipelago condition.
Can we foil in every single wave height there is? Abosolutely not, but our boats outperform regular boats in comfort in weathers where you'd normally bring out your 8 meter daycruiser/open boat.
It's also worth remembering that in rough seas, you can go down from the foils with no issue. You just cut the efficiency down to regular boat levels...
Even if not foiling, can you still take the boat out with, say, beaufort 8-9 weather? That's more similar to what I was expecting in the "high waves" videos, and is not unusual to encounter when commuting or spending the day elsewhere, depending on your area (obviously, it starts being unpleasant if you want to spend the day at sea on a speedboat).
Edit: now realizing it, but your target market is probably only going to go out with calm weather in protected seas, given the price point and finish. I hope that sort of product will get mainstream at some point.
My boating skills aren't that fresh anymore, despite living on one during my childhood, and spending a good chunk of my youth close to the sea. I might thus misremember or exaggerate things, but I am fairly confident of the above.
Below that it seems to me like it behaves more or less like a regular boat. Regardless, I'd probably avoid speeds above 10 knots if I found myself in relatively high seas, and I'd just avoid going out in that kind of boat altogether if I had the option. If you do find yourself in that kind of sea though my experience is that most swells tend to come from one direction so you can find a good bearing surf the waves, zig-zagging if need be. Adjusting speed as need be is crucial in rough seas for sure.
It does have a reasonable draft without the foils extended it seems, 1 meter, and at 2.4 meters wide it seems like it could be pretty stable actually. It'll be interesting to see once my buddy gets his delivered.
The reality is that it's the sea state that matters. A sheltered lake or estuary could only have 30cm waves with 40 knots of wind, whereas the open sea would have a 1.5m+ swell with 1m waves on top.
Open water with a low probability of colliding with anything near the surface? Yeah, this looks like a blast!
The dynamics of a sailing boat are far more complex than a motor boat. The drive comes from halfway up a huge lever (the mast) over the foils and its position relative to the forces produced by the foils is constantly and suddenly changing both on its own due to gusts and shifts in the wind and also caused by the sailor's inputs.
A motor boat pretty much only has to deal with going up and down over the waves.
It's like the difference between solving a linear equation and a higher order differential equation.
Just because you can buy a boat, that doesn't mean you can afford a boat.
Obviously it depends on what you're going to use the boat for, but for me personally it's all recreational. Boating makes me happy, and as much as I'll cuss and swear every time I have to do maintenance and upkeep I still think it's worth it.
I'm sure you know the old adage of the two happiest days in a boat owner's life: the day you buy the boat, and the day you sell the boat. Still, we never learn. :o)
17 knot min foiling speed sounds quite fast, especially for water skiing in any sort of surf, but the Candela looks fantastic for getting around the lakes / bays on shorter hauls.
I don’t do enough miles a year boating to care about the minor amount of fossil fuels I burn. I would be really interested in the foil tech with gas powered outboard. The foil boat must be must much more fuel efficient with a gas motor?
I'm not sure how much worse the efficiency is at lower speeds though, and there's almost always lower speeds involved for extended periods as you move through no wake zones.
Additionally, emergency capacity might be an issue (an extra fuel can isn't really possible), and if you do run out of power, it's not like someone could offer one or bring one, you're really looking at a tow, from what I can see.
Very cool though.
Note: I used this[1] for some quick info on what kind of fuel efficiency the bowrider got at different speeds, and used fuel tank size to estimate range.
The foil would get damaged pretty quickly, before actually killing most of the fish it comes into contact with.
The concept is very very old and well known. So there must be practical reasons why this was not commercialized.
However, the foil can take quite a beating.
Regarding commercialization, which is a great question in itself, our experience tells us that it's due to: 1. It's hard to build controllable foils, especially in a "miniaturized" size like a 8 meter boat. 2. the technology to enable sufficient speed of electronic foil control hasn't been cheap nor good enough prior to the advent of consumer drones & smartphones.
Is it to maintain a set height or change height too. I know that too high, and the boat becomes unstable.
I know that retracting the foils is a simple thing, relatively speaking.
However, if you are actually controlling the foil angle, isn't the technology available for decades? I mean there are cooling water pumps that change the impeller vane angles during operation at 400 - 700 RPM, there are helicopter blades that change angles, ship propellers can also change angle during operation, etc. There are many examples.
What technical problem have you specifically overcome in this case?
We then use the outputs to control the angle of attack, along the longitudinal axis of the foil, essentially twisting it. The R&D that has gone into making this work reliably enough for a consumer product is our secret sauce.
Anyway, congrats on the product. It feels awesome.
>How many boats have you delivered?
>As of March 2019, we have delivered 10 boats to customers in Sweden, Finland, Austria, the US and the British Virgin Islands.
>When can you deliver?
>We still have a few production slots available for deliveries for the summer of 2020. Scroll down and go to the order page to reserve one.
Fiberglass is relatively easy to work with requiring very little tooling investment. You can also easily "clone" other boats by taking a mold of the hull.
This means there are A LOT of mom and pop shops making amazing boats all over the world.
12 boats for these guys seems pretty good to me. Its very unproven technology and boaters don't like that. The sea is a rough environment and most wil prefer tried and true solutions with long supply chains for parts and service.
Be careful about this. In a truly strange exception, american boat hulls are protected by US copyright law... the dreaded DMCA.
"Title V of the Digital Millennium Copyright Act, the Vessel Hull Design Protection Act, provides sui generis protection for an “original design of a useful article” (where “useful article” is limited to boat hulls)."
https://www.law.cornell.edu/wex/vessel_hull_design_protectio...
Larger boats with a cabin and accommodations are common as party boats but this seems a bit too small.
Remember that boating is very locally adapted, with many boat models from Sweden never being exported to other regions, due to regional preferences and sea conditions.
A super nice diesel boat like this would cost 20-50k. And 50 nautical miles range is... not much. I love boats, but it's hard for me to imagine the use case here. Hopefully it's like Tesla and all improves very rapidly (price, range, etc) after the early batches.
This is plenty of range for day trips throughout the Spanish, US, and British Virgin Islands. You could do multi-day trips if you planned your overnights at the various marinas with power hookups (e.g. Scrub Island, Cooper, etc.)
Or indeed the Stockholm Archipelago, which I imagine is what this is designed for.
A 22 kW charger, like a semi fast one you'd find on the road, which is about a 1/5th of the strength of a first gen Tesla Supercharger, would fill our battery 0-100% in 1.5 hours.
I agree that's an insane price for a boat under 30 feet, but new boats are stupid expensive these days.
E.g. https://www.boattrader.com/boat/2019-pursuit-s-288-7560060/
> High frequency data logging for enhanced
> support and fleet learning
When will manufacturers finally learn that these are NOT pros, they are very serious cons‽‽‽
I do not want my data sold, and unless you plan to pay me a rate I set, my data is not an asset you can use in developing your business.
We could have gone for trying to make people quit buying, using and spending on boats, but that seemed a lot harder than creating a better alternative to regular boats.
5 years of R&D, sweat, tears and big load of broken foils later, we are in full production with a boat that reduces local emissions by 99%, compared to fossil boats.
And guess what, boating could arguably also be done with a 100% reduced emission footprint. It's called sailing.
Btw: what did I miss that owning and operating a boat is one of the biggest outdoor activities (especially small motorboats?)?
As far as the tech goes: it looks interesting, but safe the "we are making the world a better place" part.
Our boats consume roughly 1 kwh per NM, from the grid. Swedish electricity generation emits about 15g of CO2 per kWh. That's even better than 99%.
Even in the US, in 2013, with 500g of CO2 per kWh, the emissions from a Candela are still 85% lower. And at least 99% lower locally in the water where the boat is being used.
It would be fantastic if all boating was done by sails, but saying that's the solution is like saying Tesla shouldn't have innovated on the automobile because there is already a technology for moving around on roads: bikes.
Do you suggest that nothing should be done about emissions on the water?
maybe speed is a problem here. and if you are slow, it's a lot less.
Also burning at least 50€ (I'm not sure about tax exemptions for nautical fuel, but in Europe 1.5€/l is very likely) for a short trip of ~30km back and forth (which you could hike in a day - though not on water) underlines that whatever you consider "boating, the mass hobby" is something done (to great environmental cost) by a very, very small minority.
And yes I'm all for taxing the people with enough money to burn today so that they won't have to do that tomorrow - and reducing emissions of global sea trade as well.
Mostly, that's throwing money into a hole in the water, but...
The homepage claims superior ride and comfort in bad sea states.
Although hydrofoils are limited to about 400 tons, apparently, there have been several successful naval missile boats used by both sides in the Cold War.
Wings in ground effect is another thing that’s cool.
For a limited definition of bad sea states--the FAQ says the limit before you might unexpectedly land is about 1m wave height, which wouldn't be a serious issue for an ordinary boat almost 8m in length [1].
That said, I do think there's a place for hydrofoils on sheltered bodies of water. There is (or was, 10 years ago) a regular hydrofoil ferry service that runs between Petrozavodsk and the island of Kizhi [2], which cuts travel time dramatically compared to a traditional ferry.
[1] https://www.rms.nsw.gov.au/maritime/safety-rules/before-boat...
https://www.youtube.com/watch?v=wJLnJx9SzR8
https://thesarnian.com/guernsey-history/condor-1-hydrofoil-f...
I went on one once. It was disappointing. Going above decks was no longer allowed, so it was a bit like a very bumpy airplane ride with everyone sitting in their seats and nervously eyeing the sick-bags.
Limitations on sea states. This gets dangerous when the waves very suddenly start striking the hull. The hull doesn't impact the bottom of the wave but mid-wave, slamming into it in a way a normal hull never would. Limitations on cargo capacity (too heavy and it won't 'fly') which is why large hydrofoils are normally limited to passenger services. Increased draft at low speeds (ie when not flying). Moving parts below the waterline are always a fouling hazard. When that delicate foil hits something it doesn't end well. Outboard engines are mounted in a way to survive such events by folding backwards. A lifting foil cannot do that.
These all lead to a dangerous senerio. Say you are driving a hydrofoil in increasingly bad conditions. Because you are 'flying' slightly above the waves you don't notice that they are getting worse. Then one slams into the hull at full speed, or something breaks, and you can no longer 'fly'. The non-foil boat would have turned back long ago, but because you were flying above most of the waves you are now deep into a situation your craft was never meant to handle.
Sure, it's perfectly doable to put hydrofoils on any type of hull, especially passive hydrofoils. We tried, and it wasn't especially nice, nor efficient.
The trick is to use fully submerged ones. But those are much harder to keep stable, as they are inherently unstable. That's were our secret sauce is. We can control them through software similar to what you see in drones. Also, we've created the mechanical and structural components necessary for wave handling.
You won't find this type of innovation, especially the software, in any other boat in production. That's the new stuff.
or would the software installed in one of the many sailboat designs using foils prevent their high accident rate?>
Show me an electric (or dead-trees powered for that matter) boat made for one person that can foil or at least plane and maybe I'll be interested.
For reference I made this bike which weighs the same as the person it transports and has batteries that last 10 years for $300 at almost the same range/speed, the bike including everything is $3.000 so 100x cheaper:
https://translate.google.com/translate?hl=&sl=auto&tl=en&u=h...
Do you also think that a Tesla Model 3, transporting 5 adults, but weighing in at above 1500kg is a bad idea?
Electricity is not an energy source.
EROEI is already below 10 on the dead trees we use today (down from 100 a century ago, that's 10x or 1000% down).
And you need dead-trees to build nuclear and hydro. Solar and wind are useless.
A weight ratio of equal between transport (including energy storage) and transported is the only solution.
Personally I find the half weight of lithium to not compensate for the complexity/price, so I recommend lead-acid.
Can you expand on what you mean by dead-trees are needed for nuclear and hydro?
And can you expand on what you mean by solar and wind are useless?
Based on what I've seen EROEI seems to be for wind, solar not so much due to product costs, but wind seems to be above the 7 threshold.
Solar and wind are not something you can decide when you want it and the EROEI is only ok if you subvention the manufacturing and/or grid with dead-trees, when you look at it from a system perspective they are utterly useless.
The numbers only look good through the debt lens.
Both solar and wind have very short lifespans.