Electric ferry uses a long extension cord [video] | Hacker News Reader

Electric ferry uses a long extension cord [video]

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338 pointszdw224 comments

Electrified marine transport is an interesting challenge, though there are a few options available.

Notably, canal and river traffic can rely on electric traction provided by onshore "mules".

That terminology is borrowed from the original practice of having mules haul barges along canals, and reveals the immense enhancement in efficiency of water-borne transport. A single mule might haul a cart weighing a tonne or so across level land (and far less climbing any sort of grade). The same mule could haul a barge on a flat and still canal carrying 20--40 tonnes of cargo or passengers.

For passengers, the comfort of canal travel (no jostles, bumps, or broken axles as with a coach) was an immense improvement. The effect of the Erie Canal, a four-foot-deep (1.2 m) ditch from the Hudson river to Lake Erie was immense in opening up the US interior in 1825. Further, canals and their locks mean that the work of lifting (or lowering) cargo is done by the "roadbed) (the river) itself. In the case of the Erie Canal, 172m (565 ft) of elevation gain in net.

This is the origin of the term towpath:

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

This is the only context I have ever heard "towpath" in. What other contexts are there?

Oh, only that context, it's just that when I first heard of the C&O towpath I didn't understand why it was called that.

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

Not a new idea: Chevaux électriques, meaning "Electric horses" (electric towpath tractors, halage=tow).

https://de.wikipedia.org/wiki/Treideln#/media/Datei:Courchel...

https://de.wikipedia.org/wiki/Treidellokomotive

http://ronfleur.centerblog.net/6408563-halage-des-peniches-p...

https://www.ronquieres.org/le-village-de-ronquieres/vieilles... (last image bottom right)

http://www.traitsensavoie.fr/spip.php?article308

http://www.traitsensavoie.fr/IMG/jpg/cheval_electrique_bethu...

http://papidema.fr/traction_vn_extra.php#chevaux-elec

Not a new idea...

FWIW: I wasn't claiming that.

FWIWI wasn't claiming the contrary juste expanding with something I thought interesting. Replies are also intended for everybody else on HN.

Fair enough, and strongly agreed on the last.

No need to “well actually…” someone just for discussing something interesting

"Yes, and ..." is a wonderful notion from the world of improv:

<https://www.liveabout.com/yes-and-improv-game-2713213>

It contrasts with "no, but", most often, though also "well, actually", as you note.

(This is of course a "yes, and ..." comment. ;-)

And thank you.

I love this, never thought to apply it in that way. Thanks!

So I think it's interesting we had these at the end of the 19th century. Battery electric automobiles were also invented really early. It doesn't mean it's a bad idea unless you have a bias for new things

Electrification is fairly easy once you have generators, motors, and even modest transmission infrastructure. Many early generator plants were for quite limited service areas, or even single applications such as a factory or electrified rail system. Some of those later expanded to sell surplus or additional power, Duke Energy (now the Southern Company) being once such instance, I've recently learned.

The basics of electrical traction design were optimised to a large extend fairly quickly, especially relative to ICE technologies, which are relatively more complicated, and high-power (as well as high-reliability) ICE propulsion took considerably longer to develop. So, 1860s--1920s or so for electrical vs. 1890s--2000s for ICEs, which saw improvements in basic design, metallurgy, machining, emissions controls, injection, and computer controls, among others.

The alternative was steam locomotion, which was still being used in the West into the 1950s, when diesel-electric traction largely replaced it. China didn't retire its last commercially-operating steam locomotives until the 2010s, and possibly later. (There's a set of photographs of a train engineer who'd graduated from steam to high-speed rail over his career, and possibly within only a decade or so.)

In the past decade or so we've seen increasing limits on ICEs, most especially of their fundamental characteristic of carbon emissions, whilst EVs are benefiting from incremental advances in battery and other technologies reaching past a critical tipping point.

Almost no newly commercially available thing is a “new idea”, because the theoretical possibilities are typically explored well before a practical implementation is designed, built and brought to market.

> That terminology is borrowed from the original practice of having mules haul barges along canals

The Panama Canal has mechanical mules, but they are only used to keep ships on course, not to propel ships (https://en.wikipedia.org/wiki/Panama_Canal_locks#Mules)

Disadvantages of towing are that it requires a towpath alongside the water, that overtaking is difficult, and that making tight turns can be difficult (the puller always pulls the ship closer to the canal or river shore, requiring the use of the ship’s rudder to keep it on track. In tight turns, the pull direction is closer to orthogonal to the shore, requiring more rudder)

Because of these, I think battery-powered ships with container-sized batteries that can easily be swapped may be a better solution.

If you could supply the mules like electric trains are supplied, you might just as well replace the powerful mules with lightweight power pickup runners that the boats connect to with a cord. Boats would only need a few minutes of battery power for situations that aren't as easy as running straight along the canal.

At that stage, just have overhead power lines for the boats… might spoil the scenery a bit though.

Exactly, chuck a pantograph on the boat and it’s job done!

The difficulty I think is that there aren't many board purpose-built for canals: they are purpose-built for canals and rivers and many navigable rivers are to canals like oceans to the rivers, much wider and unpredictable environment. That also makes that "pickup runner" idea I posted much harder than I first thought, and pulling mules (modern as well as actual). Historical pictures of badge towing show astonishingly long lines, I believe that this is because rivers tend to have wide shallow waters between the part that is deep enough for navigation and the part that is dry enough for a tow-path.

The good news is that multimodal boats should work just fine, might even be easy to make the electrified parts support enough autopilot to allow the time to be used below deck for engine maintenance and the like. Barge operation is mostly waiting anyways and getting rid of the last instances of unscheduled interactivity might be really easy (if it hasn't been achieved yet? Primary obstacle is that the market just isn't very big)

My guess would be that a wheel on a rail turns torque into force more efficiently than a propeller in water.

The mule can travel on an overhead rail, or have mules on each side.

Mules on each side compounds the already somewhat problematic passing problem, unless a canal consists of independent channels for each direction of traffic. That's only possible in some cases. For large shipping canals with locks, there may be distinct channels for a portion of the trip. In most cases though canals integrate with river, lake, and sea-based segments which would make that more complex. River-based mule tows would already be quite challenging in most cases.

"just" install vertical pairs of rails along both side of the canals. top rails goes south. bottom rails goes north. Pulling engine attached to the rail. Have a rule that the bottom rail tethered ship disconnects before crossing incoming vessels. The crew then reconnects to the trucks after passing. Make sure the cable are high enough that other ship can pass under. Or both ships disconnect. Or top rails ship has an arm that lift the slacked cables during the crossing, and the bottom rail ship has an arm that dunks the other cable bellow the incoming ship during the passing.

Rail or battery rail powered rail cars (basically an engine and a hooking system) on the rails pull the ship, positioned on the canal.

The rail trucks can have big V shape receivers for the crew to throw the tether ends to reconnect without having to stop and come ashore.

Of courses you then have to look at the cost and general burden of installing all this infrastructure, maintaining it, ensuring the safety of having the trucks not crushing anything, making sure the boat arms can ensure trouble free crossing.

But yay, you save a lot of fuel and it might be more efficient than the boats propelling themselves.

Or maybe for inland barges have some medium sized batteries, recharged at each lock, where you already have infrastructure, possibly with pantograph. There are already a bunch of these type of projects for buses with quick charge at multiple bus stops across their routes.

No need to install thousand of miles of pantographe cables above every canal. If the locks are too far, you can install the overhead lines every 10s of miles, on long straight with clear rules of passing.

Small fusion generators.

TAE, helion energy and ZAP energy are 3 well founded companies (combined $1B+) aiming at building ~50MW generators based on non-tokamak fusion.

The generators are small enough to fit on a truck and could easily power the biggest container ships.

If you've got the ability to build fusion generators, you've got the ability to create carbon-neutral analogues of existing fuels.

You've also got that ability without nuclear inputs, from conventional renewables (solar, wind, geothermal).

Those fuels can be far cleaner than bunker fuel, and a diesel or kerosene analogue burning in a well-tuned ICE or turbine would have limited negative effects. The marine-propulsion pollutants of most significant concern, aside from (fossil) CO2 are particulate, NOx, and SOx emissions.

All are far more prevalent with heavier fuels, and are concentrated largely along shipping lanes far out to sea, other than at ports. These tend to settle out / mitigate reasonably quickly, and I believe their long-term ecological impacts are fairly minimal.

The problems with nuclear marine propulsion are many, not the least of which are the 100--200 shipwrecks logged every decade or so, though you can add to that risks of piracy or terrorism involving nuclear propulsion. Keep in mind that present commercial fleets are on the order of eight thousand vessels. We've had experience with only about four hundred nuclear-powered vessels, virtually all military ships, of which about 170 are presently operational. The exceptions are three demonstration commercial vessels, the Otto Hahn, Savannah, and Mutsu, all of which failed to prove feasible, and a handful of Soviet-era icebreakers, now operated by Russia.

Fusion itself remains both technically and economically infeasable for any foreseeable future.

<https://old.reddit.com/r/dredmorbius/comments/3c52ll/shippin...>

There is this misconception that fusion is far in the future. But these startups are aiming at commercial fusion before 2030. For instance, Helion plans for net electricity by 2024, in two years. Maybe the employees and the investors of these companies are fooling themselves and this will never happen. But they could succeed...

I am just providing pointers so people could have a look and juge by themselves. I was pretty convinced by Helion and ZAP, less by TAE.

Because we are on HN, I can mention that Sam Altman invested $375M of his own money in Helion, so he is indeed a true believer.

I think the expectation is that fusion is still a very risky bet. The upside is large (or at least perceived to be large) so a lot of funding has gone into it, but the actual chance of a breakthrough large enough is still small

Fusion power was ~50 years away in the 60s, and still ~50 years away in the 90s. If it’s down to ~10 years now, that’s truly remarkable!

My hypothesis is that the years are getting longer.

Gah! The present commercial shipping fleet is eighty thousand vessels, not eight. Lost a 'y' there.

About 1/3 of that is devoted to liquid fuel transport (oil tankers), a percentage which is down from the 1970s when it was roughly half the global shipping fleet. The absolute number of tankers has increased AFAIU, but other carriers, particularly container ships, have increased in fleet size faster.

There are also bulk solid (coal) and gas / LPG (natural gas) fuel carriers, though both are smaller than the oil fleet AFAIK.

And though I focus on shipping, synthetic hydrocarbon analogue fuels would also be useful to aviation. Probably the only way that large-scale long-range commercial flight will remain viable, if it does at all.

Tankers have also gotten smaller, at least at the top end.

The big 500k+ Ton (and that’s not a typo, we’re talking about 8 times heavier than the largest battleships ever built) ULCCs like Knock Nevis and Seawise Giant went to the scrapers a decade+ ago.

For some of the pulsed fusion concepts like helion and zap, they're either very close to technical viability or to finding an unknown (at least by outsiders) deal breaker.

I'm much more sceptical on the economic viability. If it's past the edge of possibility with known materials now, there's no reason to think your reactor would suddenly last decades because you made a series kf incremental improvements from needing 10x the energy in as out to sorta do it once to 0.95x

"are small enough" => "would be small enough"

A serious question is the size of the fusion generator. They typically have volumetric power density far lower than a fission reactor or an internal combustion engine. I don't think they will fit in a small truck.

The suggestion is clearly fantasy.

Is this true of helion (ie. Does the plasma density more than compensate for duty cycle and small reaction volume)? They publish some of their stats, but I wasn't willing to put in the effort to turn it into an actual power density figure.

I do not have the data to compute their power density. They are still going to have limits on the power/area of radiation hitting the first wall; the impulsive nature of that radiation will make the problem tougher.

Aimed at building != actually exists or will ever exist.

The day we have fusion generation so small to be run on a cargo ship we also have teleportation.

I guess that helps explain how the ferry was only using 100 liters of fuel per day. Pretty high hanging fruit for electrification in that respect.

Something about many comments rub me the wrong way, which seems common on hackernews on some topics --lots of speculative or "why don't they just.." comments when one can easily look up the reasons for cable ferries existing.

Cable ferries (which this is) are simple and well-established. Cables guide the ferry from one side of water to the other, making operation safe, simple and repeatable, even in fast moving water. They deliberately have the cables lying on the floor. This keeps them out of the way of passing ships, and is the simplest solution. The winch part of the system must be on the ship, not the shore. It's very efficient for the ferry to pull itself along the cable. There have even been handcrank operated cable ferries. It has some other benefits, like acting as an anchor perpendicular to currents. No take up is required on the other side. It's scalable to long distances without having to add piers or towers. In this case, a power cable from one shore was simply added to replace power from diesel generators. This seems to throw people off into a tangent about batteries.

Why don't they just put batteries on the ferry? This mostly assumes that the ship is driven by a propellor and the cable is adding an unnecessary tether. But cables are already there serving other purposes, so it's a simple solution to lay a power cable along the same route and no real benefit to use batteries instead.

Why don't they just pull it from the shore? You would have to overcome the drag of the cables all the way from the shore to the ferry, the power and size of the cable would have to increase dramatically and it would be impossible to scale beyond some (short, I suspect) distance.

Why don't they just make the cable higher like a ski lift on each side to pull the boat? This would require a massive amount of tension, again increasing the size of the cable required. Like a ski lift, in practice you'd need the cable to go from one shore to the other and back in a continuous loop. This is definitely more complex, and loses some benefits of the cables, especially easily letting them rest for passing ships. The engineering problem and safety aspects, considering water level and side load from current would be much more difficult. It's not scalable without adding something like towers or piers.

Yes, the "pull the cable from shore" thing doesn't work well for simple reasons.

This is what the cable looks like with the ferry pulling itself across:

                 _-OOOO-_
    ____________/        \__________

This is what it looks like if it is being pulled from shore:

    ---------------OOOO-_
                         \__________

The cable has quite a lot of friction with the bottom and can pull the ferry without lifting up and blocking half the river. Boats still need to be very careful around ferries like this, but they can still coexist.

These ferries traditionally used to be "chain ferries" which had even more friction between chain and river bottom.

If I was in Hollywood I'd call Tom Scott and give him whatever he needs to make whatever he wants. Imagine something like a long form road trip documentary, stopping in at interesting places and doing interesting things but with the pull and budget of a studio behind him.

There is a long line of very popular YouTube stars who have tried to transition to making more "mainstream" entertainment content (TV, movies) and have failed spectacularly. Large YouTube channels have fine tuned all aspects of their production to be surfaced by YouTube algorithms and consumed by YouTube audiences. Making engaging content for Netflix/HBO or a movie theater is a completely different problem.

Just upload it on YouTube. Problem solved.

Yeah whenever I've seen a favourite creator put up an out-of-place piece of long form content, it sometimes even gets a calendar entry so I can give it my full attention later

Tom Scott tried to transition into TV years ago, once you view his delivery and not-liking-of memes through that lens it gives his character a new angle.

> If I was in Hollywood...

Hollywood essentially destroys almost everything it touches: the people that invest in film production insist on maximising their RoI at the cost of petty things like artistic integrity, historical accuracy, and such.

I enjoy independent video producers ("creators" is the term now, I gather?) on YouTube (and Vimeo, etc) like Tom Scott precisely because it isn't Hollywood.

What does he need the pull and budget of a studio for?

He has mentioned a few times now that he struggles with developing ideas and script writing, and is essentially bottlenecking his pipeline. I'd imagine a well picked writing team that doesn't lose sight of what makes his content great would be welcome, but also I don't doubt over the years he's explored this at length already

Fair enough. Although surely he could afford a writing team if he wanted to have one. I know this obviously isn’t a fair apples to apples comparison, but Linus gets like double the views and is able to employ 80+ people to work on the videos.

It would be interesting to hear Tom talk about his business, the way e.g. CGP Grey often does on his podcasts.

He already has a sizable production team including several researchers (which he recently publicly mentioned). I think the fact that Tom Scott is simultaneously a presenter and writer for his channel made it difficult to outsource the writing process. He is extremely good at delivering his own script at natural voice, but that's not guaranteed if anything changes.

My grandparents made a documentary years ago[0], they started on their own and interviewed the family but once HBO got involved in the project they were able to do things like get into the courtroom for a parole hearing. Few people would talk to them, but the same people would bend over backwards for HBO.

[0]https://m.imdb.com/title/tt1024663/

You know, I've been interested to observe why some YouTubers succeed hugely and others just stay specialty channels. For example, Tom Scott assembles stories that you possibly could find elsewhere, but what is it that makes his videos special to have gotten so many views in the 10s of millions?

Is it that his videos are relatively short and digestible in 5 min, and have some off-the-beaten path / uncommon / eye catchy subjects?

Does he just make the right combination of detail and high level takeaway?

Is it that he actually goes to the places to get live footage (versus those Youtube regurgitaters who explain a topic never having left their desk, with 200 ADD-style stock footage clips in a single video)?

Is it that he frames each video with a larger more philosophical question?

Is it because he has a friendly face?

I watch a channel with some quirky British/London guys on weird things about the city (https://www.youtube.com/watch?v=cTLCfl01zuE, https://www.youtube.com/watch?v=Na9iO_HEe14) but it has never taken off like Tom Scott (-- and this is amusing, despite Tom Scott having initially been the guy who designed their intro clip). Maybe it's just too local (no so-what for me) to feel like it's broadly interesting, or they don't lead out to the bigger theme so-what?

Maybe there's just some confluence of x-factors that propel certain people to fame.

Map Men definitely took off. Over 1M per video for the past few years. They (he?) just don't make enough videos to grow as fast as Tom's channel. YouTube rewards consistency A LOT.

Yes, I'm sure that's a factor too. Also, one of my first reactions was, unless you have an explicitly comedy kind of channel, maybe somehow audiences don't seem to reward British-style quirky humor that Map Men is full of. I love it, but maybe it causes people to feel it's not "professional" or professor-ly enough? Tom Scott definitely doesn't do humor, at most only wry ironic suggestions. The Map Men sponsorship endings themselves have been hilarious (Surfshark, NordVPN, Audible, etc).

> Tom Scott definitely doesn't do humor, at most only wry ironic suggestions

Tom absolutely does humour, but its the dry British variety as opposed to the quirky British variety.

Jay Foreman, the Map Men guy is actually an extensive collaborator with Tom Scott. I seem to remember Tom Scott did some video titles for him.

Also interesting is that Jay's brother is Beardyman the beat boxer that was a YouTube sensation some years ago with his cooking show!

https://youtu.be/K7NIxKseRus

I think it's because he records his videos in one take :)

Does he? I hadn't noticed. And do you think that's something people do notice and draws them in to watch?

He's always been the "one take" guy for me. And it's not as easy as it looks--he'll spend 10 minutes wandering seemingly-aimlessly around London, and pass by a certain landmark within 5 seconds of mentioning it in his script (which he also memorized). It's bananas and I don't think many people even consciously notice. That's why he's so happy when he nails it. I think it's cute! https://www.youtube.com/watch?v=hgRRFRaMFcc

With a bit of practice, you can nail this too. The trick is to have a few seconds you can add or remove with some comment/fact which you can leave out for timing.

You'll often do it in regular conversation with people - if you're in a hurry for some reason, you can explain something to someone quicker by leaving out some less important details.

Does he still record in one take? I'm pretty sure that's changed over the last few years as his production has changed from "guy with phone camera" to "actually having a semblance of a a crew".

There's also changes in camera angle, cuts to other views, etc.

I've been trying to pin down the formula Tom uses for a while now, and I've identified at least a few common factors.

Tom sticks pretty strongly to an upload schedule, for a start.

His videos also tend to be in the sweet spots for watch time.

His videos all follow a formula, with no start/end padding of note, so viewers tend to remain engaged for the whole duration and not click away or terminate the video early.

His scripts, delivery, fucking clothing choice, everything are all super consistent - which makes his content "familiar" for viewers (even, as one friend said, "comforting"). Tom Scott, the British chap in the red T-shirt, is a pretty solid and recognisable "brand".

Its also worthy of note that his videos entirely dispense with a lot of the "YouTube meta" (soyface thumbnails, YOU WONT BELIEVE..., clickbait, etc), which makes them feel more trustworthy and you never feel like you wasted your time watching some BS.

One of the things I do find interesting though is how Tom has mentioned a few times that production cost on those videos has grown - he has a crew, editing people, video folks, etc. Its no longer just Tom and a camera phone or gopro. However the end viewer sees fuck all difference between early and later videos, barring slightly better camera work (which could be natural learning over time), and better video quality (cameras got better).

Tom Scott did indeed present a TV show with Colin Furze... demonstrating, along with my other comment on this thread, just how small the world of successful YouTubers is

https://en.m.wikipedia.org/wiki/Gadget_Geeks

Someone pointed out a while back that the best way to gain success on there is basically to collab with someone already successful in the same "niche".

It basically acts as an endorsement of sorts.

Alternatively, start (or stage) a fight with them. A LOT of "YouTube drama" is deliberately staged engagement-bait.

How to destroy a YouTubers career in 2 easy steps.

For those interested in this, there is also a quite large battery powered ferry operating in Norway.

>The Bastø Electric is 139.2-metre-long and 21-metre-wide and was built by the Turkish Sefine Shipyard and has room for 600 passengers and 200 cars or 24 trucks.

>Bastø Electric uses batteries with a capacity of 4.3 MWh. The fast-charging system has a capacity of 9 MW.

https://www.electrive.com/2021/03/02/worlds-largest-electric...

Around a quarter of all ferry connections in Norway have been electrified. Often there's one electric and one regular diesel ferry operating in tandem. Bastø Electric is still the biggest one though.

While not fully electric, there's also the Color Line ferry operating between Sandefjord and Strömstad[0]. I happened it be in town for its inaugural voyage and it turned out to be a quaint little trip. As far as I understand it though, they more or less only run on electric power when navigating out of port, and back to diesel when at see and arriving. Enjoyable trip nonetheless!

[0]: https://www.colorline.com/sandefjord-stroemstad/color-hybrid

Hurtigruten also have two exploration cruise ships that with hybrid propulsion. I think they mainly use the electric part when close to shore and in harbour.

While Norway is to be admired I find it difficult to see their experience as applicable to the rest of the world when they have a 1.19 Trillion wealth fund which equates to over 22 million per person in Norway.

America invented the airplane then went to the moon. We started every large tech company. We essentially created or popularized everything that defines the modern era.

Excuses are why infrastructure and politics here sucks. We should bully the federal government for their failure here, just like Biden bullied LGA into renovating

Well, we also have a significant fraction of the population who think that the federal government does too much as it is. Even during the moonshot, there was a lot of pushback on the federal spending on the project.

It’s actually $220,000 pr person.

I don't think the wealth fund has much to do with this: it doesn't seem like it's significantly more expensive than other options, and indeed the video implies it's a cost savings over diesel. I do agree that this isn't really a general purpose solution, as it's not feasible on wide or busy waterways. What makes it work for Norway is that they've got a lot of little inhabited islands.

Washington State Ferries are working on electrification as well. If it works near plan, it should be an operational cost savings, and hopefully that'll pay for the capital costs.

Also, electric service upgrades should increase my home utility reliability, so that's nice for people on the island I live on.

Supposed to be less noisy which should be nice for aquatic life.

I think most electric crossings are fjord crossings, not island connections. Typically 2-6 kilometers.

You can watch the live value there: https://www.nbim.no/

I wonder if these electric ferries have diesel backup systems? A little 100 horsepower backup engine wouldn't use much space/weight/cost, but would still be enough to get the ship slowly home in case of other failures.

The energy required to move a ship isn't proportional to speed - so just a little slower saves a lot of energy.

Sort of off topic but the war in Ukraine has brought to my attention that we actually fire missiles with giant miles-long extension cords. Missiles. With extension cords.

I think those are just for control & telemetry. The actual missile has a battery on it usually.

Hardlines sound much harder to hack, except literally. Which brings chain-shot (I think they did this in cannons at some point) back to mind.

Anyone got a source for this? I’d be interested to learn more

https://en.wikipedia.org/wiki/Wire-guided_missile

I think the TOW missile is the most prominent example.

MILAN is very slightly older and probably just as widely used - especially out of US.

Those are wire-guided missiles, usually used to destroy tanks and other armed vehicles. The length of the wire is just few kilometers. The wire is needed to actually tell the rocket where to steer [1].

More modern approach to anti-tank missiles are those with lasers being used for highlighting the target [2], while the missile has a battery and a camera to find the spot. The other approach is to do on-the-fly image recognition [3].

Edit: interesting fact: DART space craft sent by NASA to hit an asteroid used a missile derived technology to recognize the image and steer itself into the target, since direct control from Earth was not possible due to communication lag [4] (also try googling "dart mission" to see google's doodle on the topic).

1. https://en.wikipedia.org/wiki/Wire-guided_missile

2. https://en.wikipedia.org/wiki/Laser-guided_bomb

3. https://en.wikipedia.org/wiki/FGM-148_Javelin

4. https://www.nasa.gov/press-release/nasa-confirms-dart-missio...

> The length of the wire is just few kilometers.

“just”

Wait, what? Why?

- Can't be jammed

- Simple

- No radio frequency indication of an incoming missile.

There must be other reasons as well.

I agree with the first and last point, but reliably unrolling a 4km wire while going 500 kmh cannot be simple.

They seem to work quite effectively, I've never seen a TOW fail. Downside is you need to maintain visual guidance of the missile through it's whole flight path.

While I don't doubt you, I will say that, technically, I've never seen a TOW fail either.

I'm envision that classic "look down and see a pile of rope unspooling around your leg right before you disappear out of frame" shtick.

Anyone involved in RC aircraft will gladly tell you that getting a stable radio link for video and control past 4km is anything but simple.

Even a basic analog video signal is orders of magnitude more data than what you'd be transmitting in a phone call.

Luckily, I am involved in RC aircraft. If my 5mm, $15 ELRS receiver can do 13 km without breaking a sweat, imagine what military-grade technology can do.

TOW missiles date back to 60s-70s, so I don't think they had access to tech that good at the time; for more modern efforts the Javelin (from the 90s) has equivalent range and no wires.

That makes sense, thanks. Isn't the Javelin unguided (or self-guided), though? This means it doesn't need wires not because communication with it is wireless, but because it doesn't need to communicate at all.

ah, true, I was misremembering how it did work, I though there was some guidance done by the shooter after the missile had been fired.

Isn’t it crazy how much effort we still spend as a race trying to kill each other.

As long as resources are finite, conflict is inevitable. It would be foolish not to prepare for it.

I think you have to stretch to attribute the Ukraine war to a resource competition. It's about cultural hegemony.

Or cartel like behaviour? Leader needs to look tough to survive.

Donbas region is a major industrial area for the past century.

No surprise Russia wants it.

Russia has controlled a substantial portion of the Donbas for 8 years and has simply let it rot. There's no investment or utilization of that industry.

“The Donbas represents one of the largest coal reserves in Ukraine, with estimated reserves of 60 billion tonnes of coal.”

It's only worth investing once you've really secured it against the other side retaking it.

I don't think the Donbass was ever secure against being retaken. Hence no investment.

It's still strategically valuable, because you're still taking resources from the enemy.

It also wasn't officially Russian territory. They were still playing the game of "these are separatists that just want to join Russia", so it wouldn't make sense to invest anything in what's really been an active warzone for 8 years. Officially annexing Donbas was probably always the long-term plan from the beginning, but for some reason that turned into "fuck it, let's take Ukraine instead".

It also reduces supply of many resources (for example noble gases since Ukraine is the world's biggest exporter and Russia is the second), leading to higher prices which Russia would profit from (neon prices went up 600% around 2014). In the current situation, they also didn't expect to have to wage a year or longer war or deal with crippling Western sanctions.

The eastern part of Ukraine has vast resource deposits that are worth trillions. What makes you think resource competition isn't a part of it?

The original reason for invasion (2014) was access to the sea. Logistics are crucial for an economy.

This is plain false.

Also torpedos (for example, from submarines)

Never heard about wire-controlled torpedoes before, but indeed this makes total sense. Radio waves don't travel far in water. There are quite some spectacular systems built to contact submarines underwater [1] operating in 3-300Hz radio frequencies but antennas are kilometers long consuming megawatts. Wired-controlled torpedoes would be able to easily get target guidance from the submarine. Since torpedoes don't move fast (unlike missiles) un-spooling and long distance wires should not be a problem (wires can have neutral buoyancy).

1. https://en.wikipedia.org/wiki/Communication_with_submarines

The key words are "still being used", wire guided missiles are actually an old technology. Israel suffered from Russian Saggers fired by Egyptians in 1972, a missile produced in 1963 and it wasn't the first.

I always wonder what happens to the wire afterwards.

I assume the wire is very very thin to keep it light.

That means it probably breaks down in the environment after a few years - with the time mostly depending on what type of enamel it's coated in.

We have 3 electrical ferries in Oregon crossing the Willamette but they use 3 overhead wires to deliver 3phase AC. Works great for short hops.

https://img.atlasobscura.com/dmMEj9y780YXqaTupI_kf8Iin74JjtD...

For example, the Canby ferry

I used to ride the Wheatland ferry as a shortcut into Salem sometimes growing up. I don't remember if the version I rode was electric, but apparently the most recent version has been de-electrified:

> "This most recent ferry differs from its predecessors in that it has a capacity of nine cars, rather than the six Daniel Matheny IV carried, and it has its own self-contained diesel-electric generator. As its source of electricity is now an onboard generator, the current ferry is no longer reliant on electricity from overhead wires. The overhead cable serves the sole purpose of bracing the ferry against the current."

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

Oh man! My girlfriend is gonna hate this but hitting all 3 looks worth a slight delay on the next drive through. They are close enough together that it could be a fun bike day as well. I have wanted to get the Cathlamet ferry for some time but for whatever reason it never works well with other travel plans. https://en.wikipedia.org/wiki/Wahkiakum_County_ferry

The ferries are great for bike rides, only $1 for Buena Vista and Wheatland and $3 for Canby. You can easily do all three in a day and it's beautiful countryside. Best to check before you go, they do break down from time to time.

I rode the Cathlamet ferry recently. It was great except its cash only and I had no idea. I got super lucky that someone else in line just paid for my ride.

I think this ferry between Helsingborg (Sweden) and Helsingør (Denmark) does it in the coolest way. Since 2018 the ferry has been running on batteries. Whenever it docks into any of the two ports, an ABB robot connects the charging cable.

One real cool thing here is that they have gotten it to work for 4 full years in a northern climate. That means a lot of extreme weather edge cases.

https://youtu.be/l93i87pZWhY?t=13

thats awesome it looks straight out of a scene from walle

With this setup I wonder why even have the motor on the ship? It's using an extension cord to get power to the ship so it can pull on the wire guides, but you might as well just have put the engine pulling the wire on the shore and have a "dumb" platform in place of the boat.

The wire would need to be parallel to the water at just above or below it and would always obstruct other traffic. This arrangement allows the wire to fall onto the seabed so ships can easily pass in front of and behind the ship, given reasonable clearances.

You want the engine in a place where the people who need to control it, or even kill it in an emergency, can feel what the engine's doing, and have control over that engine.

Cables are indeed pulled, the boat does not have a propeller. But the winch part is on the boat, not the shore. If on the shore the cables would either need incredible tension or incredible power to overcome the friction of the seafloor. By having the winch part on the boat, the boat can pull itself along without having to overcome the friction in the cable between itself and the shore. This way also has the advantage that the cables can be easily rested on the sea floor to allow other ships to pass by.

If the ferry uses 150-200 kWh/day, that's two Tesla batteries assuming no recharging during the day (so realistically, you could run it on one, since the ferry presumably isn't constantly moving).

Of course, the fixed cable avoids having to replace the battery every couple years, might be lighter/cheaper etc. - but it could absolutely be implemented using batteries.

(This assumes the numbers are accurate, the 100 liters of fuel vs. only needing 200 kWh seems odd.)

It would increase the weight of the boat though, by quite a bit so you'd end up needing a bigger battery. The battery also does not have 100% efficiency so add in another 10% for losses. You'd also need downtime to charge that battery up - about 15-20 hours if you use level 2 charging. Yes, 200 kwh seems oddly low.

Have you seen the massive size of that drum of electric cable on the boat? It weights definitely more than 1200 lb, which is the weight of a Tesla 100 kWh battery. So the boat would be actually more lightweight after replacing that drum with a battery.

Oh, it's a cable-guided ferry. Since it already has a guide cable, it may as well be cable powered, too. That's not uncommon, but usually the power is transmitted mechanically, like a ski lift.

Brighton Beach in England once had an electric-powered sea-going railroad with an 18 foot gauge. A ferry running on railroad tracks. More of an amusement ride than a means of transportation, like some Disney water rides that run on tracks.

I found this video about another type of crossing using a cable:

https://youtube.com/watch?v=OW24yLHmC20

I've ridden on one of those boats when I was in Basel. It was incredibly calming to cross the river with no noise from a motor.

There are also I think five different cable cars in the immediate Basel area that offer some incredible views as well.

You’ve now convinced me that I need to Basel :)

There is a link below the video to a Wikipedia article with similar ferries all over the world.

Newer ferries run by BC Ferries (in British Columbia, Canada) are being set up as optionally-electric. Two will be in service where I live soon, replacing a slightly larger single ship today.

The new ones have diesel engines running a generator, for electric propulsion. Once the mainland infrastructure is in place, they can be upgraded to run as plug-in electrics. I had a tour on one recently. Where there is one bank of lithium cells along one wall today, the room has space for another three or so.

FWIW, these are short trips, ~10 minutes each way. Under diesel power, they've made their way from a shipyard in Romania to get to Canada.

They say the ferry uses 150-200 kWh a day. If those numbers are right that wouldn't be a very big battery pack. The Hummer EV, for example, has a 212 kWh usable pack:

https://www.youtube.com/watch?v=ORKuZxrFr6A

https://www.youtube.com/watch?v=F9IUOR8lG3E

Still, it's a cabled ferry anyhow so also having a power cable makes sense.

Battery packs degrade so fast with constant use. They would replace it every year if not every month.

Nonsense; they are good for many thousands of cycles which generally translates into many years of continuous use. Mostly batteries degrade on a very predictable scale as well and very gradually.

All of this is well known and anticipated by companies that deploy batteries in ferries, and other short range boats. It's just economics. You have energy savings and a battery that is good for a given number of cycles and engine hours. Either that adds up or it doesn't. Basically, it will be years before you need to service them and you can just use math to calculate whether that's economic or not.

Apparently it does. That's why the use of batteries in short range nautical applications is booming. You have some range constraints but anyone operating within those constraints is looking at switching over already. Battery longevity is not the concern here generally.

Why not simply pull the ferry using the steel cables? In other words, put traction systems on both riversides and move the ferry using them. It even should be more efficient than a propeller-based propulsion system.

The ferry in the video uses cable based propulsion.

This is why hn needs a downvote button LOL

HN has one, it's just only accessible to those who have reached a karma threshold (501 I believe).

It pulls itself along the cables rather than using a propeller, yes, but the motor that's doing the pulling is on the ferry rather than on the shore.

To answer GP's question: I don't know, but given that this was a retrofit of an existing diesel-powered ferry I could guess that this was the cheaper way of doing it.

Yes, but the propulsion is on the boat rather than at shoreside like OP suggested (ie the cables are static)

The point is that on the current system motors which are powered by the electric cable are on the ferry, so it uses propellers to move. The proposed alternative is to use steel cables (which are already present) without any electric ones to pull the ferry, such system should be more efficient power-wise and easier to service.

So it doesnt have a cable spanning the river all the time.

But it already does have two steel cables spanning the river all the time. IIUC they get relaxed when ferry does not move and sink to the bottom to allow other ships to pass.

The cable is going to be submerged in the water and I think that you are underestimating the amount of force that it requires to drag the entirety of the cable through the entire length of the water.

If the ferry is pulling itself along using the cable, the cable doesn’t really even have to be under tension and there is a lot less stress and forces on the system overall.

This (friction or drag) is the correct answer. You would need either huge tension to keep the cables off the sea floor (and additional complexity to relax/lower as needed) or an impossible amount of power (and tension at the shore) to pull the boat. Think about how an anchor works, the actual anchor is just the end point and some length of chain is also laid on the floor. Drag of the chain, not the anchor is what actually keeps you from floating away.

Not really related but regarding energy usage: I was fascinated when I travelled in Rathen (Germany) with a ferry that uses just the power of a stream: https://en.wikipedia.org/wiki/Reaction_ferry

The German wikipedia entry has a small picture that shows how it works: https://de.wikipedia.org/wiki/Gierseilf%C3%A4hre

And the following technique seems to be even more convincing as the stream is never blocked from the cord: https://de.wikipedia.org/wiki/F%C3%A4hre#Rollf%C3%A4hre but probably more difficult for larger streams.

My guess is that there are several possible factors for this reason. Here’s some I thought up off the top off my head:

- It would be difficult to synchronize the movement of the two motors sitting on either side of the river. A single motor whose output is local to the ferry’s impulse is easier to control.

- The ferry can likely move somewhat independently of the cable, and the inverse of its current design makes this more difficult.

- When comparing the two approaches, the one with fewer moving parts in the system is typically the one that is easier/cheaper to build and maintain.

- It might be more difficult to properly maintain the steel cables if they are stressed in this way vs. the current approach.

- There might have been infrastructure already in place that made this approach easier to implement, and parts for a slightly modified boat are going to be easier to find than parts for a proprietary “raft pulled by a steel cable” system.

A very good question for which I haven't been able to find any official answers. Here are some thoughts: - Wear of the cable at the shore ends. Just as abseiling reduces wear on rope compared to lowering, ferry mounted drive means limited dragging across what could be possibly very abrasive surfaces at each shore (sand, rocks, etc). Instead cables get lifted up and lowered down gently. - A cable ferry pulls tension on one side allowing the other side to drop down. If you've ever navigated around a busy cable ferry you'll know that you don't wait for it to stop at either side, you just pass behind it based on current direction. To replicate this functionality you'd need motors for pulling from either side (which you've identified). In that light an electrical cable running to the centre is a quite efficient solution. - The ferry could require power anyway for a range of functions like raising and lowering the drawbridge (I wonder what the proper ferry term for this is).

We do that here between Vancouver Island and Denman Island

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

For those mega cargo ships, why is civil nuclear power vessels are not a thing? Seems they would massively reduce the footprint while providing better clearner power.

Servicing marine nuclear reactor units requires very special skills and is expensive. So is the initial capital cost. Servicing large marine diesel systems uses labor that is much more available globally.

Because it's all about cost. Those 400m container ships are ran by a low cost crew of 15-25 with some 3rd party maintenance personnel sprinkled in. Try fitting a more expensive fuel and more maintenance into that. On top of all safety concerns.

For ocean crossing vessels they are more closely looking at e-fuels and hydrogen since that gives the same benefitd at cheaper cost with not a too large change in the shore side infrastructure.

https://youtube.com/watch?v=cYj4F_cyiJI

On the NS Savannah, an interesting story.

Because they don't pay for pollution.

Answered in large part here: <https://news.ycombinator.com/item?id=33631996>

Cost, safety, scale (there are 80,000+ commercial vessels), reliability, crew training and costs, etc.

Combustion's highly proved, reliable, and safe technology. Range is sufficient for transoceanic transport. Emissions (both CO2 and other factors) are an issue, but could be mitigated with synthetic fuels, possibly biofuels (though even shipping would strain capacities required).

For big container ships, that's a good question. I think it comes down to: low quality diesel fuel is cheap enough, and the regulatory hurdles would (presumably) be immense.

(Something else worth noting is that about half of all ocean shipping is just moving fossil fuels around. If we could just stop using fossil fuels, that by itself could cut ship traffic in half.)

I've wondered about the viability of battery-electric ships. Crossing the Pacific on a single charge isn't realistic given current battery technology as far as I know, but it seems like it might be possible to have transcontinental undersea power lines on heavily-used routes, and buoys at regular intervals with charging ports. So you'd have a ship travel for a day, then stop a few hours at a buoy to charge. The ships would probably have a small backup diesel just in case.

With nuclear, you could also imagine ship convoys. You have one small-ish ship with mostly just the nuclear reactor that trails electrical cables that other ships attach to. No need for every ship to have nuclear reactor.

One could even imagine a government operating the power-plant ships. For instance, let's say the U.S. Navy were to operate a dozen power-plant ships that travel a fixed route across the Pacific. Any ship could, for a fee, connect to the power-plant ship and be supplied power as it makes its way to its destination, and then switch over to batteries or diesel if the convoy route doesn't go all the way there. It seems plausibly feasible.

You wouldn't want pirates capturing a nuclear reactor :| And protecting the ship at all times would be too expensive

This is pretty cool. I wonder what the effort would have been to instead have a battery charging / swapping process on one end. It would still be clean energy, charged on shore. I'm sure the batteries wouldn't be super light but you could have them in modules and you could engineer solutions for moving them.

Perhaps for situations where it isn't already cable guided this is still a practical approach. I'm pretty ignorant when it comes to the weight of the batteries and how much energy they can provide + etc… but if my Tesla is any indicator it doesn't seem too hard vs managing that cable back and forth

The batteries could even be attached cars themselves so moving them on and off would be really simple

Or with a thicker cable they could charge cars while they cross the channel.

Rechargeable batteries are not 100% efficient. I'd put good odds on this system being cheaper.

The captain said they use 150-200kwh a day, which would be around 2-3 EV batteries' worth (Model S has a 100kwh battery). That's split up between 88 trips, so there's plenty of opportunity to swap batteries.

So they could probably have some kind of battery system but I'm guessing since it's already "tethered" with a line just to cross, stringing an electrical cable was already easy to do and has simpler logistics than managing batteries.

Around a quarter of the ferry crossings in Norway are electrified. Usually there's one or two electric ferries and one diesel ferry. They charge while unloading and loading and during the night when there's fewer crossings. Before they had to take breaks during the day to charge, but now days I think they run all day.

Sort of common in the nordics. We have lots of them in Sweden, the self-service type for short crossings to sparsely populated islands, but the power cable usually drives a winch attached to a steel cable.

Thinking outside the box a bit I think there could be lots of applications for “long extension cords”. Especially when you consider how light and thin a cord could be when you use high voltage.

While annoying to route around trees and a bit of a hazard considering the possibility of running the cord over, using a corded electric lawn mower worked passably well for a small yard.

Seems like ideal use case for a battery. Use 1/week max, rest of time plugged in. I had one at my house and it was perfect for my small-ish yard.

Perhaps, my own yard is just on the cusp: one battery charge with a cordless mower gets me about 75% of the way there. One decent length extension cord gets it done in one go, and I'd much rather have it done at once rather than wait for a charge cycle.

yep, they are very light and maneuverable and not have a battery pack allows for more interesting designs. but I have run over the cord before. things went quiet for some reason.

This is an application where I find the old tech does a better job: push mowers.

I recently replaced my mower with an old push mower [1], someone local restores them and sells them for a reasonable price (much less than anything new or even a petrol or electric second hand mower.

It works so well I wouldn't go back unless I had more than about 200 sqm to mow. Modern push mowers are junk and put me off in the past, but the older ones are much heavier and better built. They cut grass cleaner than a rotary mower which is supposedly better for the grass too.

[1]: trademe.tmcdn.co.nz/photoserver/full/1857940265.jpg

> Modern push mowers are junk

They really really are in NZ at least. I saw some at Mitre10 the other day and they were pretty much all plastic, wtf?

Someone local to me as well buys second hand mowers and fixes em up, puts a better motor on etc. Works well - been a very long time since I've touched an old push mower though!

My old man runs a landscaping/gardening/mowing business so I grew up helping mow lawns etc and you're quite right they've just gotten so bad. We'd buy those commercial ones, and over the years they just got bigger, heavier and shittier - breaking all the time. Dad went back to using just basic older mowers and they work just as well.

You're correct that those old push mowers are better for the grass if you don't have the catcher on - which is the reason for some mowers having that "mulch" function (spitting cut up grass back out without a catcher).

Do you have any experience with this ?

Is it possible to have a 10KV x 100A power tether snaking around like this ?

There is a whole basket of safety requirements which kick in with higher power scenarios

They do this with large mining machinery such as the drag lines and bucket wheel wheel excavators. They don't move very far so extension cords are acceptable.

And in mining they run portable medium voltage wiring through the tunnels to baby substations. They even make plugs and sockets rated to 15kV or possibly to 35kV, the upper limit for "medium voltage" in NA.

Obviously you aren't going around plugging these cables in like they're attached to a reading lamp. They are on disconnects or circuit breakers and the circuit is de-energized before connection or disconnection. Otherwise arcing would destroy the connector. A faulted circuit would cause an explosion on connection likely killing or severely injuring an operator.

Electricians working on medium voltage circuits must have medium voltage training and certifications.

There are rather big excavators/shovels as used in mining operations, for large-volume material handling, that are powered by a tether. I guess they don't nimble around much but rather stay in roughly the same spot, filling trucks to haul the rocks away for smelting/processing.

I agree. What someone needs to invent is a good way of powering a tractor (or combine harvester) through an electric cable.

I don't follow, how are high voltage cables able to be thinner than low voltage cables?

The limiting capacity of an extension cord is the resistance it can carry - at high resistance the cord will basically catch on fire. High voltage can deliver much more power at lower resistance as compared to low voltage. The easy example is household power -- in the US, standard household electricity is 120v, so a common 14 gauge wire that can carry 12A at constant load would be able to deliver 1400 watts. If you use 240v, that same wire can deliver 2800 watts.

To extend that to extension cords -- if your boat/tool or whatever needs 5kw of power, at household voltage of 120v, you'd need a #4 wire which weighs 1.3 lbs/10 ft. At 240V, you'd need a #10 wire which weighs 0.3 lbs/10 ft. At 360v, only a #14 wire which weighs 0.13 lbs/10 ft.

So by tripling the voltage, you can cut down the weight of the cable by roughly 10x.

Thanks for the detailed reply, I really appreciate it! Now to go down the rabbit hole a bit more...

Basically, conductor weight is proportional to the current, while insulator weight is proportional to the voltage.

It turns out that our insulators are much more efficient than our conductors, so the trade-off is a non-brainier up to extremely high voltages.

> I think there could be lots of applications for “long extension cords”

Ok, now I'm wondering how much one can decrease the weight of a rocket if it starts plugged to some cable.

Any ISP gain at the beginning of the trip helps decreasing a lot of weight, but cables weight something too, and 1km or 2 of cable falling vertically is a hell of a hazard...

I have to admit, it sounds a lot crazier before you learn that there are already cables running along the channel that the boat uses. This also means that this can't generalize outside of channels that already have cabled crossings.

Given that constraint, I wonder about operating these ferries more like a ski lift then. If we're already stringing cables across the channel might it make more sense to keep them on shore away from the water?

Notably, this ferry is driven on a chain which crossed the channel already.

I suspect they would have gone for batteries if the route wasn't already anchored in

Yea, they only use 150-200 kWh per day, that's not a lot of batteries to store on a large ship like that (it's like ~5-10 EVs worth of batteries maybe? not the whole car, just the batteries!), even if you couldn't charge between sailings (which you could). I think it was probably a cost thing, too, as this system with a cable is probably way cheaper than batteries.

edit: I was trying to reinforce here that, although this application could easily have used batteries due to the low energy needed per day, it didn't because there was a better solution due to the pre-existing cable infrastructure. Certainly this cable method isn't useful for most ferries, and most ferries will be traveling further and faster and require way more batteries.

They use so little because the use the (steel) cable for traction (as I understand it) and not water. If they had to use a propeller in the water to cross a river, the consumption would be much more.

So in essence, there's symbiosis between electricity and running a cable-guided ferry. Otherwise you'd need more energy, therefore bigger batteries, etc.

I really dont think so.

There are just crossing 500m at 2-3 knots several times a day.

This is basically less than a semi rolling resistance which is maybe 1/5kwh/km?

EDIT: even so, x10 batteries 2mwh are still very reasonable for a boat which cycle daily

When he mentioned the steel cable, I wondered why they don't use an arrangement more like cable cars. It sounded like it is in case they break loose during a storm or emergency, so it useful to have the engine on board along with the back up generators.

Are the cables actually used for traction, or just a countermeasure against having to fight the cross current?

Yea, they pull themselves along the cable. The commenter above you was correct, it is way more efficient than props, plus it's way more efficient for high currents like this river. My comment was simply that they could have used batteries, but for this particular application a cable was perfect. I was reinforcing that this was a great confluence of constraints that enabled this.

I was also wondering this, you beat me to asking. If there is precedent for two cables why not connect them to make a long narrow loop of them like on a ski-lift; place an electric-powered winch on one end and an idler on the other?

Was neat to see the video, and I’m sure they have their reasons.

One reason may be that the cable sinks to the ground, which makes it possible for other boats to cross. If it was like a ski lift, the cable had to be more tensioned I guess, thus obstructing?

> it's like ~5-10 EVs worth of batteries maybe? not the whole car, just the batteries!

Batteries are heavy, batteries need recharging, batteries can explode, batteries wear out, batteries cost a lot to replace.. or you can have a cable that might snag, but probably won't if you keep tension on it.

And batteries in marine environments age much more quickly than those in dry-land applications. Salt loves anodes and cathodes.

Some teslas have 100kwh batteries. The Hummer EV has ~200kwh battery. Depending on how much extra capacity is needed to optimize for longevity of the pack, and charging, it might be far less than 10 cars worth of batteries. Potentially as little as 1.

Makes you think that there might be quite a few river ferries that could be converted quite economically.

The Ford F150 Lightning comes with either 98kWh or 131kWh of batteries depending on the package.

Wait a minute... in theory, there could be a ferry that depends on power from an electric vehicle driven onto the ferry. That would solve the logistics problem of moving heavy batteries on and off the ship. The ferry could initially use consumer vehicles and switch to customized vehicles when the economics make sense.

Unless something changes, I think the F150 lightning will be my next vehicle purchase. The electrical grid in my area can be spotty, and one of the big selling points for me is the ability to tie the truck into your house for use as a battery backup. The larger capacity truck would be the equivalent of over 10 powerwalls!

Furthermore you could charge them during the middle of the day and at night, and use the batteries during morning and evening commutes, which is pretty ideal.

As for the additional mass and displacement, the video mentions boats having to push water out of the way, but water also fills in behind the boat, so there isn't as much physical work involved as it sounds like.

Also safety, I'd guess. Fire has much worse consequences on ships than on land...

Worth noting is, the subtitles said "The ferry uses, each day, about 150-200 kWh" whereas the speaker said "the ferry uses today between 150 and 200kW". I'm guessing Tom Scott had him clarify later, but the units, and what could be assumed to be a timeframe or not, is not the same.

The boat used to consume 100 liters of diesel daily, which is equivalent to 1000 kWh in energy (10 kWh per liter). But after electrification they claim only 150-200 kWh usage per day. This doesn't add up. Were the diesel engines idling all day even when the boat was not moving?

It seems ok to me, EVs have about 13kWh/100km efficiency while an older gasoline car would consume 10l/100km. And yes, it's quite plausible that the engine was running during loading and unloading

You are right. I forgot to account for the fact combustion engines have a terrible thermal efficiency: about 20%, which gives the boat only 2 kWh per liter of diesel, meaning it was using 200 kWh daily, more in line with the electrical version.

Cool - another option could be beaming power to the ferry using microwaves, millimeter waves or lasers. The power transfer efficiency would be lower but saves the cable complexity and slacking/maintenance.

I think the losses on both sides of that invisible death ray would be more complex than a long extension cord.

That sounds like a good way to get cancer.

I’ve never seen this video but just from the description I thought, “That sounds like something Tom Scott would make a video about.”

Though I am a big fan of Elon Musk's Boring company I think his used of modified Tesla's to transport people in the tunnels isn't the best idea.

The old streetcars, like in Detroit, used to attach to an overhead wire to power themselves. I think you could have normal train cars using this method. In other words use the electric grid as opposed to batteries. I can't imagine a battery fire in an enclosed area like a tunnel.

Much better than NYC's subway using a live third rail which I believe has killed more people falling on to the tracks than the trains themselves.

Subway makes perfect sense, except when you are CEO of a car company. Then they are your direct competitor and suboptimal solution of Tesla's in the tunnel is used instead.

These are super common - all of SFs MUNI system is built using the overhead wires -- batteries in the individual cars are interesting because there's a ton of cost involved in electrifying the entire length of the tunnel to deliver as much power as a train needs. All of the substations, the physical electrical cables themselves, etc add a ton of cost to tunneling projects and long-term wear items that will require endless maintenance that often shuts down the lines.

Building a dumb cheap concrete tunnel and leaving the expensive parts in the cars themselves could be a very cost effective method of urban transport. Though I think the "use Teslas" is a dumb addition since a purpose built train car similar to the airport shuttles at Denver would be much more efficient and handicap accessible.

To clarify, the light rail (Muni Metro) and electrified bus lines use overhead 600 volt DC, but most of the bus lines are not electrified.

Electric trolleybus have been running in some cities pre-WWII [0].

I have seen them in Budapest, São Paulo, and Malatya.

[0]: https://en.wikipedia.org/wiki/Trolleybus

> I think you could have normal train cars using this method. In other words use the electric grid as opposed to batteries.

Like... most trains in Europe?

I'm amazed that you've never seen an overhead electric caternary, be it for a train, tram or light rail system.

https://www.openrailwaymap.org//mobile.php?style=electrified...

Everything except the black and pink is overhead electric, and I guess I hadn't realised how little of America is electrified.

When I clicked on this I thought, why not just have a cable-guided ferry instead? (Which already is a common thing) I assumed they'd have to make maneuvers not possible with a cable. But it already is?!

Then why not just tug the cable instead, much better efficiency then propellers.

Edit: ok, it is. Though what I've seen is that the motors are pulled from shore rather than on the boat. Which seems simpler, but this is maybe easier to retrofit.

Did anybody else know this would be a Tom Scott video before clicking it? He always finds the oddest most interesting things to show off.

Yes! I expected "this is going to be a Tom Scott video" before clicking the link. He has a niche in interesting esoteric infrastructure.

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