This is actually quite interesting from a wind-powered cargo perspective. Normally stories like this are about ships that can carry 2,000 TEUs (a measure of freight containers) while the biggest conventional ships carry 20,000 TEUs. This ship can actually carry 7,000 cars while the biggest conventional car carrier manages 8,500. It's in the same ballpark with far less fuel usage. It could feasibly replace car carriers on routes where wind is an option.
I'd pay money to be a passenger on the maiden voyage.
They should definitely include a few passenger cabins, as many freighters have. I have never been on a cruise - has zero appeal to me, but this would be awesome.
I'd like to see more detail about this project, though.
As others have commented, pure wind power is not going to be commercially feasible. There's too much variation in weather to work within current logistics demands.
They do anticipate that it will take 12 days to cross the Atlantic, compared to 8 days for fossil fuel vessels. Is that to have enough slack in the schedule to sit idle for the port entry if the winds are good and they arrive early?
But, I hope it's a success.
The Gulf Stream [1] is very real and very consistent. I think we forget the important role this system played in the rise of the United Kingdom and the United States as global powers.
As the ship also has an engine, the wind situation probably more decides about the amount of fuel used rather than the schedule.
But indeed, it would be attractive to have a passenger section.
I’m guessing that the ship is actually battery powered (or something similar) and the sails are only used as windmills to charge the batteries (or supplement the primary fuel). So unless the wind conditions are really unfavorable you can still have pretty predictable crossing times.
No, the renderings are very clearly solid wingsails. People have tried schemes like you suggest with propeller hybrids, but it's much less efficient than just a sail, and a solid wing is about 3x more efficient than a simple sail at the same area. Don't underestimate how much force can be generated by a couple 100 square meters worth of wing.
> The ship will be equipped with five retractable, telescopic wingsails that can rotate 360 degrees. The masts will measure 80 m (260 ft) for a total height above the waterline of 45 to 105 m (148 to 344 ft). That would also make it the tallest ship in the world. The rigging will be made from steel and composite materials and resemble airplane wings. An auxiliary engine will be used to navigate harbors and provide emergency power.
> While the design is meant to be usable for different types of ships, the first version is planned to be a 200 m (660 ft) long roll-on/roll-off ship with a capacity of up to 7,000 cars. Such ships will be used on transatlantic routes and are expected to perform the journey in 12 days, longer than the current average of eight.
> Open-sea trials with a 7 m (23 ft) prototype were conducted in the summer of 2020 and are scheduled to continue during the fall. Commercial orders are expected to start in 2021, with an entry into service in late 2024.
I know it's a bit impolite to doubt their math on displacement and speed and all that, but it seems like a bit of a stretch to me.
The boat is 200m long and the sails only occupy about half of that. The all-down configuration is 45m and the all-up is 105m so I'd guess the sails are about 70m tall. So 70 x 100 = 7000 sqm of sail area. That's approx. equivalent in area to a wind turbine with an 83m diameter rotor. Doing one of those online wind turbine calculators with an efficiency of 40% (limit of 59% ala Betz) comes up with about 1.5MW or a little under 2000 horsepower.
Most of the big boats like this start around 10,000 hp and only go up from there so I can't help but wonder what's going on here. I guess it could have a very efficient shape and go slower but that seems unlikely to make that big of a difference to me.
A typical large windjammer from the final years of sail carried about half that sail area on a vastly smaller ship; lengthwise about half, but the displacement/tonnage difference would be huge. So yes, this seems quite underpowered, even taking into account that the modern airfoil shaped sails are certainly more efficient and have less windage than a traditional square rig.
My guess is that the idea is that in low winds they use the engine to boost speed.
Keep in mind a solid/3d airfoil is about 3x more efficient than a bermuda rig, so it's going to be dramatically more efficient than a square rigged tall ship, particularly upwind.
The target speed is around 10 knots. Commercial cargo vessels are designed at 20-23 knots, some lower at 15-18 knots (slow steaming), rounding it at 20. So they need about a quarter of the power to maintain half the speed.
From the wikipedia article: "Such ships will be used on transatlantic routes and are expected to perform the journey in 12 days, longer than the current average of eight."
I 100% get that half speed = 1/4 drag and thus 1/4 power. That makes sense.
But I'm not sure how to reconcile half speed with not at least doubling the trip duration. New York to London is 3000 nautical miles. At 10 knots that's 300 hours or 12.5 days. If there are boats doing 20 knots then they should arrive in ~6 days rather than the 8 quoted.
It's even worse than that, for a drag force proportional to the square of the speed, the power is proportional to the cube of the speed. As for the transatlantic voyage in 12 days vs 8 or 6 I don't know on what they based it. Maybe ships don't always go at the nominal speed as it may not be economical to do so. 8 days is 15-16 knots, so this corresponds to a more economical slow steamer. As they pitch an environmentally friendlier solution, a comparison to the next best thing (slow steaming) may be more apt. Using the cube-law, ~2/3 the speed ~= 0.3 the power. And only 1/8 if you compare 10 to 20!
For a ship this size, I'm guessing that you need to factor in at least 1/2 day at each end coming and going from port, possibly a full day. It's likely that cruising speed only matters for total number of days minus 2 regardless of trip distance.
While I'm not a naval architect, but your comment is nice reminder that naval hull drag is cubic with speed:
For reference, see this document [1] from the US Naval Acadamy.
"It will be observed from the figure that the doubling of speed of the Navy YP from 7to 14 knots increases the power by a factor of 10!" [1] p.7
"Ship power is roughly proportional to the cube of the speed" [1] p.8
Hence the installed power you estimate may just work out.
I do have many questions about the about sail handling and rigging. Stowed and raising these things are non-trivial! Telescopic mechanisms can have all sorts of issues, especially when loaded - like in a building storm!
So while the entire concept really excites me, I'd love to see them iterate at smaller scale before trying to go full scale.
[1] Chapter 7, RESISTANCE AND POWERING OF SHIPS
U.S. Naval Academy:
> "I do have many questions about the about sail handling and rigging. Stowed and raising these things are non-trivial! Telescopic mechanisms can have all sorts of issues, especially when loaded - like in a building storm!"
I had some downtime while living on a marina for a bit, so I read a bunch of the research literature. Freestanding wingsails that can fully rotate like this have the neat property that they can "weathervane" with very little drag. In fact a bare mast on a traditional sailboat with the sail down generates a lot more drag than the wing, due to turbulence vs laminar flow.
It's not clear from these renders, and I'm not motivated enough to dig into it, but most designs I read about in this category are self trimming. Saildrone is a good example, where it uses a 2nd smaller wing on a boom to control the overall angle of attack of the wing. Change the setting on the "tail" to change the angle of attack. The wing will follow the direction of the wind no matter how it shifts. So controlling these boils down to a small electric actuator, which is easy to make controllable via a screen, software, or what have you.
In fact one of the motivations for people experimenting with this stuff at more modest scale is it could be huge for adaptive sailors, because it makes sail handling so trivial.
Gentle reminder that a good 100 years ago all freight ships were wind powered. I once had the pleasure to talk to someone who served on one of the German Flying P-Liners until the late 50s. His stories were more than amazing. He said that once they failed to pass Cape Horn for 100 consecutive days. On another, more pleasant trip, they had the greatest weather that a sailor can dream of, tailwind and sunshine from start until end. Things have certainly changed a lot, but relying on the weather for shipping is certainly still a challenge.
A lot of things have changed since then. Most importantly: we have weather satellites and internet. Even hobby sailors can now get precise weather information for all oceans of the world to plan their routes. Just check windy.com. A 100 years ago, there was no weather information available beyond what you saw when you looked out of the window and the current air pressure. You had to detect weather changes by the change of the air pressure. This makes a huge difference in planning your voyages.
On top of that, a modern wing sail is much more efficient than the sails used in the old cargo ships and of course, the modern ship comes with an engine. Bad or no wind will cause more engine use, but not the ship getting stuck in one place.
Amazing beauties, shame there's only a few of them left.
> He said that once they failed to pass Cape Horn for 100 consecutive days.
IIRC those Flying P-Liners were used a lot on the Chilean guano trade. So they had to go round Cape Horn against the prevailing winds on the way out. And with a square rigged ship not being the best for beating against the wind, it sounds believable.
if this ship is purely wind powered and basis on the published info this seems to be the case, i.e. there is no main engine of any type/fuel for propulsion - commercially it’s not viable.
Shipping is highly optimized for arrival to a destination/port on a very narrow time window. Even delays of a couple of hours will be extremely expensive. For example, late arrival to SUEZ means that the vessel will join the end of the convoy at a premium rate costing hundreds of thousands of USD in additional fees. Not only that, Ports and Charterers (Liners) are working basis specific arrival times, you cannot simply arrival late because the wind was not favorable.
It could work as an assisting system, such as Flettner rotors , skysails ,etc
It has an ‘auxiliary engine’ for port manoeuvring and ‘emergency power’. This ship is being designed for the Atlantic route and I imagine will be sailing with the trade winds to get more consistent winds (Clockwise around the Atlantic). The reason this is being built for roro cars rather than traditional cargo is probably due to the logistics.
It seems pretty likely that this also has a significant amount of generator capacity on board. Even small sailboats often have to run their engine or generator during passages to top up their battery.
I understand what you say. But maybe it's time to forget about that kind of time optimization and replace it by an optimization for fuel efficiency... Else we'll be stuck in the past...
If fuel savings are great enough, this could be irrelevant, and planned around.
And there could be a premium for the service. I could see Tesla paying extra to ship electric cars with burning bunker fuel. As a customer I’d pay extra for that.
Well, their website claims "90% lower emissions than a vessel with a diesel engine" so evidently they use some form of engine, or they'd be claiming 100% lower! i would guess it's like most sailing boats, and it has a small(-ish) engine and prop for use when docking/maneuvering up close/no wind, and also a genset for onboard electrical power.
You'd probably do the same thing that powered ships do: build extra time into the schedule so that you never arrive late. This ship probably needs more padding because it relies on the wind, but the whole concept seems to be that that's an acceptable tradeoff for the environmental gains.
I've said it before but I love how these futuristic sail-powered cargo ship designers completely ignore a millenia of sailboat design history. But OK, I'm sure they know better - look at the pretty CG renders!
That's right. They do know better. While the luminaries of the past were great for their time, their techniques are those of laymen compared to us, as ours will be to our grand-children. We take from the past what designs were good then and we throw away what no longer suffices. This is the nature of progress, and why road transport vehicles today share very little in common with those of the preceding millennia.
Remember, that it is not just those who say "this is new, therefore good" who are fools but also those who say "this is old, therefore good".
Old sailboat designs are old, but no longer competitive.
Old communication media (printed text, for instance) are old, but very competitive.
In all honesty wouldn’t we? We might have been refining sails and sailing for a millennium, but only recently did we get steeled hulled container ships with vastly different hull profiles and CFD modeling to tell us what’s actually effective.
Biplanes worked great for most of the history of aviation, but we can do better now with math.
> only recently did we get steeled hulled container ships with vastly different hull profiles
The hull shape of a steel hulled windjammer is not vastly different from a modern container ship of similar size. Very similar length/beam/draft ratios, both have pretty "boxy" hull shape midships. The big difference is the bulbous bow, which doesn't make much of a difference at the lower speeds a sailing ship spends the vast majority of its time, and of course the stern with the propeller.
> Biplanes worked great for most of the history of aviation
To nitpick, if we consider the age of flight to start with the 1903 Wright flyer, biplanes were mostly obsolete by the mid-1930'ies. So about 30 years out of a so far total of 118 years.
Reminded me of a company called Norse Power which is basically retro fitting wind sails to existing fleets. Still in the testing phases but they were saying that the savings on fuel etc were substantial enough to take note. Not the article I read but still some info: https://www.marinelog.com/technology/sea-cargo-to-retrofit-r...
As the OP, I'm confused why the timestamp says it was posted an hour ago when I posted it yesterday, and how it got the subtitle. I'm happy it's on the front page of course, but I don't really get the HN mechanics behind it?
From Wikipedia- it's being developed by Wallenius Marine, which is a ship design, building and management company which was spun off Wallenius Lines in 2003 but is still owned by the same group.
Wallenius Wilhelmsen seems to be a joint venture of Wallenius Lines of Sweden and Wilh. Wilhelmsen of Norway.
The web site touts that they combat climate change with a nice concept. But it's a bit ironic that the target product the ship will transport are cars, one major consumer of fossil fuels and a big source of CO2.
By the time this ship type enters service, hopefully a lot, if not the majority, of cars are electric. It is very fitting to deliver electric cars with a ship which doesn't use much fuel.
How do they plan to load/unload cargo containers from this ship? At most of the worlds ports cargo containers are loaded and unloaded from the above the ship using dock craines, but the wind sails and the (roof?) on this seem prevent that.
Under Cargo it simply says it is capable of carrying 7,000 cars in the cargo hold. It doesn't appear to be set up for shipping container cargo. It is possible that top-loaded shipping containers don't work well with the sails/airfoil that need to be above the ship.
