[HN Gopher] Hydrofoiling
___________________________________________________________________
Hydrofoiling
Author : AndrewDucker
Score : 123 points
Date : 2021-05-11 07:44 UTC (15 hours ago)
(HTM) web link (www.tbray.org)
(TXT) w3m dump (www.tbray.org)
| sethbannon wrote:
| There's a YC company that's building hydrofoil container ships to
| lower the GHG emissions from shipping.
|
| https://www.boundarylayer.tech/
| inreverse wrote:
| A similar company: https://freightfish.io/
| unwind wrote:
| Hadn't seen those, really interesting, thanks!
|
| Also can't help smiling at their use of "BLT" as an
| abbreviation for the company name, I guess we know what their
| Official Company Lunch is going to be [1]. :)
|
| I wonder if there has been any progress, the site is kind of
| ... light on the details. The prototype single-container ship
| was cute, though.
|
| [1]: https://en.wikipedia.org/wiki/BLT
| raverbashing wrote:
| Interesting, and the video is informative (though a bit short)
| but we always want to know the caveats
|
| - Why hasn't this been built before? Yes, minor hydrofoil ships
| have been built but why not cargo ones? (Constructor
| conservatism? Some issues that others have run into? Lack of
| technology before that)
|
| - How does this fare in a marine thunderstorm?
|
| - How many customers are time sensitive (but not much) so as to
| fit their window?
|
| - What kind of problems can going 4x the speed on an open ocean
| can create?
|
| - Is the actual cost 4x less once you factor everything in?
|
| My bet is that this makes sense for shorter routes (like
| multiple ferry routes in Europe), maaaybe for "shorter" cargo
| routes, not so sure for the longer routes (though China-LA is
| not "too long")
| Candelaboat wrote:
| There's a lot of vaporware out there, but this foiling ferry
| has been paid for by the City of Stockholm and will launch
| next year:
|
| https://candelaspeedboat.com/public-transport/
| nradov wrote:
| Fairly large hydrofoil ships have been built before so it
| will probably work from an engineering standpoint. But the
| economics are questionable. They're betting on finding
| customers who want a middle option between slow, cheap
| container ships and fast, expensive air freight. I'm
| skeptical that many such customers exist.
|
| Hydrofoils obviously can't operate safely in heavy sea
| states. When a storm comes up they'll have to delay sailing,
| or route around. That will add some unpredictability to
| delivery schedules.
| nicoburns wrote:
| > Yes, minor hydrofoil ships have been built but why not
| cargo ones?
|
| I'm assuming that the additional of the weight of the cargo
| means that you would need to go much faster in order to lift
| the ship up on the hydrofoils, and this makes it infeasable.
| imglorp wrote:
| Also you need to lift your fuel and you might get into a
| rocket equation type problem. Fuel is less dense than water
| so one might imagine it contributes a little to buoyancy
| but aloft, you're paying to lift it along with the cargo.
|
| Fuel means range so that all might get back to the mission:
| ferry or transoceanic.
| mannykannot wrote:
| Airplanes also have to lift their own fuel, yet are not,
| in practice, hostage to the rocket equation (though
| early, grossly inefficient jets may have experienced
| something like it.) Three things that make the rocket
| equation a problem for orbital launches are, firstly, you
| have to take along the oxidizer as well; secondly, you
| have to do much more lifting (and, considerably more
| significantlty, accelerating) than an airplane; and
| thirdly, without dynamic lift, all the lifting and
| accelerating has to be done directly by engine thrust.
|
| Also, while fuel oil is buoyant, it still has mass and
| weight, and the fuel in a ship contributes its own
| weight's worth of displacement. Displacement, in turn,
| causes wave resistance.
|
| The larger a ship gets, the less significant,
| proportionally, both wave and friction drag become,
| reducing the incentive for foiling. It seems significant
| that the YC company mentioned elsewhere in these comments
| (Boundary Layer Technologies) positions itself as
| competing with air freight rather than shipping (and, as
| flying in the thin air of the tropopause is pretty
| efficient compared with generating lift in water, I would
| guess part of their calculation involves building much
| larger-capacity vessels than current and projected air
| freighters.)
| Candelaboat wrote:
| Check out our foiling ferry P-30 that already is paid for by
| the city of Stockholm and will be launched Q4 2022:
|
| https://candelaspeedboat.com/public-transport/
| adolph wrote:
| It is interesting that the illustrations use traditional
| looking props rather than ducted or shaft-less rim-driven
| thrusters.
|
| https://www.researchgate.net/project/RIM-DRIVEN-THRUSTER
| sails wrote:
| Hydrofoiling seems to be having something of a grassroots style
| renaissance, with incredible interest across all of boating,
| sailing, windsurfing, kitesurfing, surfing and pretty much any
| other board/boat water sport.
|
| I find this peculiar because hydrofoils were seemingly much more
| common in the 80-90's in industrial applications such as ferries,
| but now suddenly have become hugely popular in recreational
| space, and rapid innovation in the design and construction of
| foils across all of the domains. Very interesting if you are
| interested in boats and water sports.
| JJMalina wrote:
| Foiling has made it possible to do all of these sports with
| less power. I can now go windsurfing in 12kts on the same size
| sail that I would use for 20kts.
|
| I remember seeing foils in the late 90s and early 2000s but
| they weren't available to purchase. I wonder why. Maybe it's
| because the construction process hadn't been commercialized
| yet.
| mechhacker wrote:
| Yep
|
| I've been hydrofoil windsurfing (and have tried
| wingsurfing/wingfoiling as well).
|
| Hydrofoiling has extended the lower range of wind speeds that I
| can go fast in. For instance, around 10kts wind I can pump the
| board and sail to get on the foil and go about 20mph. Pros push
| this even lower, to about 7kts wind speed.
|
| I can also go upwind much higher and downwind deeper, at speed,
| than I could with just regular windsurfing on a fin. Control is
| a bit difficult downwind for me, still, but it's fun.
|
| Paris Olympics in 2024 will have hydrofoil windsurfing. There
| was also a race this weekend around Lanzarote, which was almost
| 10hrs of racing and 130 something miles traveled on windsurf
| foils.
| Candelaboat wrote:
| Mikael at Candela, the C-7 maker, here. Hydrofoils have a
| number of benefits, among them are: less slamming (up to a
| certain sea state), less drag and better fuel economy, and
| smaller wake. Boeing 929 Jetfoiler from the 1970's onwards and
| the Russian hydrofoils that were produced in large numbers
| during the 1950's-1980's largely used hydrofoils because they
| made smaller wakes (Russian river rockets) or handled choppy
| water well (Boeing, in Hong Kong and Japan).
|
| At Candela, we use hydrofoils to reduce the energy usage, to be
| able to make an electric boat that has long range at high
| speeds, above 20 knots. Conventional hulls are hard to
| electrify since they need so much power. However, we use a new
| type of hydrofoil: fully submerged hydrofoils, that are more
| efficient but needs active stabilization from computers and
| software. The on-board Flight controller adjusts the hydrofoils
| at 100 hZ, or 100 times per second, which makes for a craft
| that won't pitch or heave. This tech was available in the
| 1970's - it's basically a very similar Flight controller as in
| an inherently unstable jet fighter like F-16 - but thanks to
| drones and smartphones, the price reduction of sensors makes it
| possible for us to offer this tech in a leisure boat.
|
| And - we're scaling our electric hydrofoil tech to commercial
| ships. Right now, we're starting the construction of the
| world's first foiling electric shuttle ship for the city of
| Stockholm. At its launch next year, Candela P-30 will be the
| fastest electric ship ever at 30 knots, as well as most energy-
| efficient ship ever built. Energy usage is 1/10th of
| conventional diesel ships. Check it out here:
|
| https://candelaspeedboat.com/public-transport/
| usrusr wrote:
| The 1980ies did not have foil sailing which is just incredibly
| inspiring. And that in turn is most likely enabled by carbon
| fiber manufacturing having become somewhat mainstream (and much
| better), even if it may not be entirely impossible to do in
| steel.
|
| Also, for industrial applications (and for recreational without
| self-imposed restrictions), high frequency automated active
| servo control is now very much in the realm of practicality.
| Back then it was all self-stabilizing, which led to some very
| bumpy rides.
| seryoiupfurds wrote:
| Well, there was the Hobie Trifoiler.
|
| http://trifoiler.info/media/index.php?title=Main_Page
|
| https://www.youtube.com/watch?v=zXSgZCDVWOM
|
| I don't know if modern consumer-level designs are
| sophisticated enough to be using much CFD, but it definitely
| seems like the easy availability of CAD should be playing a
| role.
| modernerd wrote:
| Hydrofoiling might be old but lithium batteries and electric
| motors have spawned a bunch of eFoils companies (electric
| hydrofoils):
|
| https://fliteboard.com/
|
| https://liftfoils.com/
|
| I get friends who aren't into surfing sharing links to these
| things just because they look so fun.
|
| They're not quite Gravity Industries[1] cool but they have an
| "Iron Man on water" feel to them, and they're an interesting
| entry point into watersports for people who can afford to buy
| or hire the things.
|
| [1]: https://gravity.co/
| iancmceachern wrote:
| I've been wanting one of those electric foil boards for a
| while. There are patents involved which is why the market
| hasn't exploded yet, but some folks have been making their
| own DIY versions with pretty great success:
| https://foil.zone/t/filips-budget-3d-printed-hydrofoil/1968
| hyperpallium2 wrote:
| I saw one of these electric hydrofoil surfboards in the
| distance off the beach last thursday.
|
| It looked like a landspeeder, and felt like watching a fake
| youtube video.
| modernerd wrote:
| Land Speeder and Speeder Bike eFoils are crying out to be
| made.
|
| The closest thing I found was the "HydroFlyer":
|
| https://www.thehydroflyer.com/
|
| The riding position is somewhat different to an efoil
| Speeder Bike, though, where your legs would presumably
| start in the water like with this design:
|
| https://foil.zone/t/efoil-motorcycle/6432
| chrisweekly wrote:
| Wow that looks like fun. And while $13k isn't pocket change,
| it's about the same as a new motorcycle or high-end (e-)MTB.
| IOW not totally inaccesible pricewise. hmm...
| ako wrote:
| Maybe carbon fiber technology has improved and has become more
| affordable?
|
| I'm in the proces of learning to use a kitesurf hydrofoil, it's
| funny to see the gps tracks from a smartwatch on strava, very
| messy, like a child scribbling.
| londons_explore wrote:
| Am I correct in saying the key difficulty of a hydrofoil is
| making sure the boat never gets too high (and the hydrofoil
| leaving the water, causing massive mechanical stresses on the
| supports and failure) or too low (and the boat slamming into a
| wave at high speed, causing a very sudden stop and injured
| passengers)?
| Candelaboat wrote:
| Mikael at Candela, the hydrofoil boat maker, here. Yes, that's
| a key difficulty that has to be solved by using sensors that
| detect flight height, and distance to the waves, among other
| things. If the foil leaves the water, you ventilate and come
| down. We use a flight controller, a kind of computer, to
| perform these calculations. Some sailing boats have wands, ie a
| mechanical stick that detects waves in front of the boat,, but
| using ultrasonic sensors and adjustable hydrofoils is a way
| more accurate solution. Check us out here: candela.com
| SahAssar wrote:
| This is explained on wikipedia:
| https://en.wikipedia.org/wiki/Hydrofoil#Foil_configurations
|
| Basically, yes, for fully submerged hydrofoils you need to make
| sure you don't get too high or low. For surface-piercing you
| don't, they self-stabilize.
| krupan wrote:
| Skiing or wakeboarding behind this would be pretty rough except
| on really smooth water. What else do people use a little boat
| like this for?
| Candelaboat wrote:
| Waterskiing behind a Candela C-7 here:
| https://www.youtube.com/watch?v=pAMlAcSEI1I&t=10s
| jrwoodruff wrote:
| I don't think you -could- wakeboard behind this, right? The
| whole point of wakeboard boats is to displace as much water as
| possible in a controlled way. Skiing would be interesting
| though.
| krupan wrote:
| You could wakeboard, it would just be kinda boring without
| the wake :-)
| dzhiurgis wrote:
| Charging these by marinas with solar shade seems obvious fit - it
| protects the boat from weather plus their batteries can balance
| grid as they are only used like 0.01% of time.
|
| Question I have - do hydrofoils use ground effect to generate
| extra lift?
| sesuximo wrote:
| I'm guessing no because you have to travel pretty fast for an
| air wing to have an effect (~50-200mph), but you travel
| relatively slower for the hydrofoil to perform well (10-30mph).
| (These are very approximate numbers I made up from experience
| riding on different types of boats. They are not physical
| limits or anything like that!)
| dzhiurgis wrote:
| I think TeamNZ were talking about supercavitation for next
| foils so speeds can go well over 100km/h in next few years.
| barbegal wrote:
| Water is considerably different to air and there is no
| analogous effect for ground effect in water.
|
| Edit: I realise now that you mean hydrofoil as in the boat
| rather than the submerged wing (it's confusing that they both
| have the same name). I don't think the ground effect from the
| boat's hull contributes much to the lift but it is something
| that the designers of the AC75 boats take into consideration
| https://www.sailmagazine.com/racing/36th-americas-cup-differ...
| nixy wrote:
| I think the OP is referring to ground effect above the water
| surface, as employed by for example eraknoplans
| (https://en.wikipedia.org/wiki/Lun-class_ekranoplan)
| jojohohanon wrote:
| I would speculate no, as it seems a trade off between
| inherently stable and inefficient (standard v shaped hull)
| and inherently unstable, but more efficient (inverted v).
|
| Ekranoplans have wings and aerodynamic control surfaces.
|
| I also wonder (this may be the primary reason) if the
| speeds a hydroplane achieves are sufficient to generate
| much lift in air from something the size of a boat hull.
| mrfusion wrote:
| So why aren't hydrofoils used almost everywhere? Who wouldn't
| want less drag?
| SigmundA wrote:
| One mistake going too shallow and you will probably rip the
| foils off doing significant damage to boat. Thats my theory why
| they aren't more popular except in specific applications. Fuel
| costs are always an issue with boats and foils are well known
| to reduce them along with smoother ride.
|
| Most normal pleasure boats regularly go in shallow waters and
| pull up on the beach etc. If you look at the skegs of any of
| these boats you will see where they have dragged or struck
| something and a normal outboard doesn't stick down anywhere
| near as far.
|
| It's cool the the Candela can retract the foils, but again
| forget to do it one time and those foils looks very expensive
| and what do they do to the hull as they are being ripped off.
| Candelaboat wrote:
| Mikael at Candela here. Because it's super hard to make the
| control system for an inherently unstable boat. It took five
| years of R&D to make it work in all manners of situations,
| banked turns etc. Conventional boat builders don't have access
| to software and control systems engineers, and tech companies
| seldom invest in the marien sector. But once we got it working,
| there are no real drawbacks, only benefits. Smooth, quiet, and
| fun to drive. Check out candela.com for more videos.
| jpm_sd wrote:
| Big waves and high winds will cause your vessel to go unstable
| and crash. Ocean-crossing cargo vessels have to handle all
| weather conditions.
|
| Hydrofoils significantly increase draft and nobody wants to
| dredge their ports and canals 20 feet deeper.
|
| Also drag is proportional to velocity squared, so you can save
| a ton of fuel just by slowing down a bit. Much easier than
| designing a hydrofoil cargo ship.
| nradov wrote:
| Many hydrofoil designs are retractable so in ports they don't
| draw much more water than a conventional displacement hull.
| Agreed on the other points.
| SigmundA wrote:
| Only if you remember to retract them.
| breck wrote:
| This is anecdotal but in the past ~5 years I've noticed foils
| popping up in more and more places (in Oahu).
| rmac wrote:
| Has anyone seen hybrid propeller / jet-pump boats or foils?
|
| It seems like it would make sense to have a gas engine and
| propeller to get the foil on-plane from stopped, then when
| "gliding" switch to a battery powered jet pump to keep it at
| speed.
| kbenson wrote:
| The Candela boats he links to were discussed here[1] a while
| back, in case anyone is interested in that discussion.
|
| 1: https://news.ycombinator.com/item?id=24222208
| uncoder0 wrote:
| Sailing has pushed Hydrofoiling to the next level there are 100m
| boats coming out that claim to be able to do 2.2x wind speed
| downwind. One of the things I miss the most living in Central
| Texas is sailing on trapeze and foiling. If I were back near the
| coast I'd buy one of these: https://iflysail.com/
| nixy wrote:
| Candela will also provide boats for a trial with the Stockholm
| Public Transport system, which currently employs quite a few
| traditional boats for transport around the city.
|
| https://www.mynewsdesk.com/candela-speedboat-ab/pressrelease...
|
| https://candelaspeedboat.com/public-transport/
| w_t_payne wrote:
| My friends also have this electric propulsion startup:-
| https://www.radpropulsion.com/
| korse wrote:
| I take it the author hasn't heard of E-Foils or jetfoils?
|
| Maybe not a family transport option, but we're talking a
| surfboard filled with 18650 cells (or similar) riding on a
| underwater wing driven by a jet or small propeller.
|
| They are relatively old with companies building competition
| models at least five years ago.
|
| The technology at heart is an outgrowth of the portable electric
| vehicle industry and hydrofoil development in the windsurfing
| commnity.
|
| If you think this article is neat, I would check out the
| technology. You can build a performance board yourself for sub 3
| grand US (possibly less if you are willing to vacuum mold the
| board yourself).
|
| Good resources are available from the portable electric vehicle
| or electric skateboard communities. Board building has been
| covered in depth by generations of surfers.
| pp19dd wrote:
| Engine lost compression in two cylinders on my 5.7 GL Volvo
| Penta. ~ 300 HP, leaky exhaust riser. Took the opportunity to
| look into an electric option that can bring a 4,700 lb boat on
| plane, comparable power that is in production and available.
|
| - Evoy hurricane inboard, 600 kW: NOK 1.497.000
|
| - Battery pack: medium range, 252 kWh: NOK 1.476.000
|
| In US dollars, that's $360,000 and I'd have to ship it from
| Norway. Closest second option was about half that price using BMW
| i3 batteries, at half power. Meanwhile, a new marine engine was
| $10,000 by comparison, or to repair exhaust and rebuild to last
| another 17 years, $5,000.
|
| Boating is a luxury and I can't excuse it in environmental terms,
| same as I can't excuse electing not to walk 2 hours to my local
| starbucks for a consistent grande pike I enjoy in favor of
| brewing my own. But marine electric is currently nowhere near
| being a practical solution, and you cannot hydrofoil in all
| boating conditions, especially in choppy waters, or where there
| are seasonal floating obstructions.
|
| Boats do have notoriously small efficiencies (1-4 mpg) in both
| displacement and planing modes, but consider that for an
| automobile to have its 25 mpg average we pour approximately
| 124,000 gallons of crude oil per mile every 5-10 years for a two
| lane asphalt road, a coarse byproduct of refined petroleum.
|
| My whole point here is not to equivocate in any terms, but that
| it's easy to overlook externalized costs. Moving an object
| anywhere is a difficult problem.
| Scene_Cast2 wrote:
| Wait, don't foils handle fine as long as the chop is within
| reason? And if the waves are higher than the foil clearance,
| it's not like regular boats would do that well either.
|
| Worst case, couldn't you go slower and just act like a regular
| boat?
| pp19dd wrote:
| Imagine cruising at 30-40 mph, angled so you cut through
| waves perpendicularly. Mostly you head straight, but you do
| need to lazily avoid some crests and troughs, aiming for that
| sweet middle. You then see a mostly submerged log 30 feet
| ahead, just barely under the surface.
|
| You now have two choices, steer to the left or right of it.
| Those split-second decisions have consequences, depending on
| which way the prevailing waves are headed. Say if you turn
| toward port, you might be parallel to the waves which you
| never want to do: they can capsize you. So you don't turn to
| port.
|
| Heading toward starboard might be a better choice, but it's
| still not perfect - you might head toward a crest that will
| definitely slam into your bow violently. Or there is another
| boat wake you now have to deal with that wasn't a problem
| seconds ago. In either case, you need to alter your speed to
| either avoid it or cut through it more gently. You start
| dropping off plane, cut through a favorable section, and then
| angle yourself and go wide open throttles to miss a trough.
| Maybe you rise back on plane before you avoid it, or just
| slightly afterwards but on most V hull powerboats doing all
| this is not a problem. In normal traffic, this might happen a
| few times a minute.
|
| But hydrofoils have two things going against them right
| there. They have massive drag at lower speeds and thus
| maneuver poorly in an emergency, taking more time to
| accelerate on plane or change direction. Then the weight
| ratio is a challenge: they need a lot of power for cruising
| speed, so they weigh more than you'd expect and then weight
| management is one of the primary design concerns. That all
| means the propeller is optimized for power over acceleration,
| and that means that these three congruent design choices have
| painted you into a corner, limiting collision
| maneuverability. Hydrofoils handle rough seas far worse than
| any conventional hull shape and more importantly, colliding
| with anything underway is far less forgiving than striking an
| object on the bow or outdrive.
|
| Emergencies notwithstanding, being normally outside a
| propeller's designed operating range and you have cavitation
| and ventilation problems, which then erode the propellers.
| And that weight constraint means fewer seats, fewer people to
| carry, so less efficient per capita.
| Candelaboat wrote:
| Mikael at Candela, the maker of C-7, here. This post is
| inaccurate and frankly makes no sense. First, the waves
| will never capsize the boat. Due to low cog, it's virtually
| impossible to do - we've tried. You can manoeuvre just fine
| at all speeds, but at high speeds it's correct that you
| might not be able to avoid running over a log or other
| submerged objects. Same goes for regular planing boats at
| high speeds. If you hit something, the foil will withstand
| smaller objects - branches, debris - but is designed to
| come off should you hit a bigger object, such as a log.
| While the foil breaks off, the hull will stay intact and
| avoid damage. Now, on the other hand, if you hit a log with
| a conventional boat, there's a risk the hull is pierced and
| the boat sinks. Regarding the "weight ratio": hydrofoil
| boats are super energy efficient and need very little power
| at cruise speed compared to a traditional hull, which is
| why we use them for C-7. At 22 knots, the C-7 uses about 25
| hp, which is pretty remarkable for a 25-foot boat. We have
| a passenger capacity of six persons, but have actually
| taken off with 10 persons on board - using a motor rated at
| 65 kW!
| SigmundA wrote:
| How much does it cost to replace the foils should you
| tear them off? Because honestly on a pleasure boat say in
| Florida where I am your not going to hit a log but you
| will drag bottom at some point due to shallow waters and
| tides. Most outboards have some sort of skeg damage due
| to dragging bottom or strikes. Replacing props and lower
| units or repairing the skeg is very common.
| karmicthreat wrote:
| My guess would be treat it like when you pull the chute
| on a Cirrus GA aircraft. Total loss, but you didn't die!
| pp19dd wrote:
| Mikael, my hats off to you and your fine product and
| sweat you poured into it. My apologies if in any way I
| seemed to criticize performance of your craft, far from
| it. I know nothing of it, and electric is going to be the
| only way in the near future. The context got shifted
| toward it somehow.
|
| My general skepticism regarding hydrofoils comes from,
| quite frankly, not seeing that much damage with them
| because they don't exist 'in the wild' so much here to
| establish a conventional sense for most U.S. east coast
| watermen. Plenty of other issues that everyone I know is
| familiar with, most commonly groundings and striking
| objects, and occasionally catching cage lines on props.
| The petrol-era weight bias sticks around and this is
| where I hope you show us very wrong. I'd love to see some
| rough water videos of your C-7.
|
| My original response from where everything else stemmed
| from is that right now this isn't a practical conversion
| for a common man with something like a 27' cabin cruiser,
| certainly not in the pocketbook. I do not know how much
| the C-7 costs, but was my sticker shock that far off?
| Candelaboat wrote:
| Hi, no problem, just wanted to clarify. The price is 250
| 00 euros, which indeed is expensive for a 25 foot boat,
| but still about 100 000 euros less expensive than
| conventional electric boats that can go fast - but not
| that far.
|
| The price stems from a high production cost, the whole
| boat is built like an aircraft, in carbon fiber (the
| designer used to work at Eurocopter) to be as light as
| possible. The weight of the hull and deck is about 240
| kg. So our main goal for the future is to reduce the
| costs - by a lot. But think about C-7 as the Tesla
| Roadster. But our foiling ferry for the city of Stockholm
| will be launched next year, and then people using the
| Stockholm public transport system can go foiling for
| 2EUR.
| Candelaboat wrote:
| Mikael at Candela, the maker of C-7 here. Yes: The hydrofoils
| reduce slamming by about 95% in waves that are up to 1,2
| meters. If they're higher than that, you can always go slow.
| The boat has a 40 kWh battery pack in the keel, so it's a
| very stable craft even at slow speeds. Check out Candela.com.
| acdha wrote:
| Is biodiesel getting much interest in boating? Given the cost
| disparities I wonder whether it'd make more sense to explore
| emissions controls with a non-fossil fuel until a better
| battery technology emerges.
| bosswipe wrote:
| If the goAl is reduction of emissions or generic environment
| friendliness biodiesel is not a solution. Especially if the
| biodiesel comes from palm oil.
| acdha wrote:
| It very much depends on the source - palm oil is a disaster
| but if there are alternatives it seems like it would be a
| net win for CO2 if you could avoid additional fossil fuel
| extraction. I'm thinking of a guy I knew who used to
| process oil from a local restaurant's deep fryer - that
| would be problematic getting the formulation right for an
| advanced car engine but my (possibly completely incorrect)
| understanding is that marine Diesel engines are a lot
| simpler and there isn't an obvious path for short-term
| replacement the way there is for an EV.
| magsnus wrote:
| ~840 HP (1.4*600) to bring it up to plane with an electric
| motor but just ~300 HP to do it with a diesel engine? It's
| obviously more expensive but not that much more expensive.
| pp19dd wrote:
| Check out the electric co's site, and maybe it'll explain it
| better than I could have at a broad pass. But that inboard
| was their entry-level motor that actually existed.
|
| I suspect their power declaration is marketing language
| claiming burst power, and that its nominal cruising range is
| well under it but regardless of any of that, the batteries
| costing $180,000 is still an issue.
|
| Edit: forgot one important thing for that power matching, the
| weight. Replacing an engine and full gas tank -- the electric
| motor + mid-range battery pack overall adds about 2,500 lbs
| to the boat, so it'd be a 7,200 lb boat at that point and I'm
| not sure I could trailer it anymore.
| LeifCarrotson wrote:
| I'm not sure what you're putting that in, but there's been some
| increasing noise in the ski boat world for electrics (eg. [1]
| and [2]).
|
| Electric power density in either volume or weight is OK in a
| car, where once you've accelerated you're rolling on low
| resistance tires on a smooth surface and the weight is less
| important. But in a boat you're fighting the equivalent of the
| rocket equation where the force on your planing hull has to
| have more batteries to lift more batteries to go farther.
|
| It's fine, though, for a lot of watersports uses, where you
| want to put out hundreds of kW for a few seconds to pop a skier
| up, do a set, talk to your skier without asphyxiating them in
| exhaust fumes and without shouting over engine noise, and then
| plug it back at the dock. Less fine for cruising, where you
| want a tank of fuel to last you whole day. You only need enough
| energy storage to outlast human quads and forearms, not more to
| outlast human bowels!
|
| [1] http://www.ltsmarine.com/english/lts-water-ski-boat/
|
| [2] https://nautique.com/models/super-air-nautique-
| gs22e/overvie...
| timbray wrote:
| Note that the Candela people have videos of their boats running
| smoothly in waves up to 1.2m.
|
| People used to say that electric cars were "nowhere near being
| a practical solution" until suddenly they were.
| aidenn0 wrote:
| The spec sheet for the C-7 says "Wave height 5 cm when
| foiling[1]."
|
| The C-7 is a toy. I have no doubt that they can make a non-
| toy at some point in the future, but the future isn't here
| yet.
|
| 1: https://candelaspeedboat.com/candela-c-7/
| Candelaboat wrote:
| Hi, I work for Candela in Sweden. 5cm is not the wave
| height the boat can handle. 5 cm is the height of the wake
| the boat produces, so almost no wake. You can go foiling in
| 1,2 meter high waves in 30 knots - check out this video:
| https://www.youtube.com/watch?v=m7I0pVpnytM&t=8s
| aidenn0 wrote:
| Thanks for the clarification. Could you maybe update your
| product page? As someone who lives on the open ocean
| (rather than a bay), the first thing I look for is
| maximum swell or wave height a boat can handle.
| Candelaboat wrote:
| Good suggestion - thanks!
| inetsee wrote:
| I have to say that I think the Spec Sheet may be in error.
| I looked at the videos on Candelas website, and it looks to
| me like there's significantly more than 5 cm between the
| water surface and the bottom of the hull.
| pp19dd wrote:
| Water under all those videos on their homepage is what
| we'd basically call smooth as glass. That's definitely a
| calm +/- 5 cm wave range.
|
| Here is what a 1.2 meter one looks like, just exiting an
| inlet: https://www.youtube.com/watch?v=rV41E9PQwiU
| Candelaboat wrote:
| Mikael at Candela here. It's supposed to be "wake", not
| "wave" - sorry for this. The wake behind the boat is only
| 5cm, so no wake damage here:) The boat handles waves
| nicely, we can fly in up to 1,2 meter high waves - watch
| this:
|
| https://www.youtube.com/watch?v=m7I0pVpnytM
| 0xbadcafebee wrote:
| > People used to say that electric cars were "nowhere near
| being a practical solution" until suddenly they were.
|
| FWIW they were the most common automobile type at the turn of
| the 20th century. The naysayers were just internal-combustion
| apologists.
| Gravityloss wrote:
| Another solution that increases efficiency is to travel slower
| and design the hull for that. Non planing boats look like
| sailboats or retro motorboats.
|
| Most boat owners can't afford a hydroplaning boat.
| [deleted]
| usrusr wrote:
| Isn't that a bit of a tautology? Most boat owners can't afford
| a boat. (Talking about recreational of course)
| Gravityloss wrote:
| No. Hydroplaning boats cost multiples of regular boats.
|
| Three kinds.
|
| Regular planing boat. Cheap and fast but very inefficient and
| thus can't be electric.
|
| Hydroplaning boat. Fast, efficient so can be made electric.
| But very expensive.
|
| Non planing boat. Cheap, efficient. Can be made electric. But
| is slow.
| hnzix wrote:
| TFA cites speed as a constraining factor for their particular
| needs: _" attractive for the "tugboat" flavor of pleasure
| boats. Which is perfectly OK unless you want to cover some
| distance and get there fast."_
| ansible wrote:
| A sailboat is the original "carbon free" way of propulsion for
| boats and ships. No, it is not as fast as a hydrofoil, but it
| also won't run out of power except under rare weather
| conditions (utterly becalmed).
|
| Not that boats don't do a lot of environmental damage in other
| ways. Bilge tanks, anti-fouling paint flaking off, etc.
| sesuximo wrote:
| Anti fouling is the only thing I can think of that's really
| bad about boats. The rest seems ok/not worse than living on
| land.
| gnopgnip wrote:
| For a cruiser a hybrid electric system has a lot of benefits.
| Basically it uses the conventional diesel engine, prop, gearbox,
| and adds an electric motor that bolts on. So if something goes
| wrong, all of those parts can be serviced worldwide. The electric
| motor is a form of redundancy, and can also be used as a starter
| if the starter fails, and the diesel motor can function even if
| the electric motor fails. At low speeds the electric motor only
| is used. The electric can be used at the same time for some extra
| power. For short trips with shore power you can get around
| without using any fuel. And you can recharge while cruising with
| the electric motor working as an alternator, allowing you to
| spend most of the time on only electric, extending your range.
| dzhiurgis wrote:
| Some boats charge batteries via shaft while on sail. Otherwise
| diesel generators aren't mechanically connected.
|
| What I do wonder is whether automotive range extenders can be
| retrofitted instead of marine gensets. Seems way cheaper.
| jeffreyrogers wrote:
| > The core ideas behind the Candela C-7 aren't that complicated:
| Electric powertrain, battery, hydrofoils, software trim control.
|
| I enjoyed the article, so I'm not trying to pick on the author
| too much, but I always find it funny when technical people say
| this about engineered things. Each of those things is literally
| an entire discipline and you could still spend a career (or at
| least many years) only working on one of them. I think we have a
| tendency to think that because we can understand something and
| have taken some of the magic out of it that it isn't complex.
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