After seeing [Veritasium]’s video on Blackbird, [Professor Kusenko] contacted him and said the performance claims and explanation were incorrect. After a bit of debate [Veritasium] proposed a wager on the matter, which [Professor Kusenko] accepted, and it was made official with a written agreement witnessed by [Neil deGrasse Tyson], [Bill Nye], and [Sean Carrol]. From the start, it was agreed that the entire debate would be made public.
[Professor Kusenko] made a very thorough and convincing argument, backed by calculations, against the claims in the video. He claimed the observations were due to a combination of gusty winds, a vertical wind gradient. He was convinced and that the vehicle would not be able to maintain a speed higher than the wind, directly downwind. By [Veritasium]’s own admittance, his original video could have contained more details and proof of performance claims of the Blackbird vehicle. He added these to the latest video and included two model demonstrations. The model that brought the concept home for us is at 13:46 in the video, and substitutes the propeller for a large wheel being driven by a piece of lumber being bushed across it. The second model, built by [Xyla Foxlin] was designed to demonstrate the concept on a treadmill. The 4th version of [Xyla]’s model was the first to be successful after she found out from [Rick Cavallaro] that the key design detail is the Vehicle Speed Ratio, which must be 0.7 or less. It is the pitch of the propeller divided by the circumference of the driven wheel, assuming a 1:1 gear ratio. All the 3D files and details are available if you want to build your own downwind cart. Continue reading “$10 000 Physics Wager Settles The Debate On Sailing Downwind Faster Than The Wind”→
If you search the outer reaches of the internet you will find all sorts of web sites and videos purporting to answer to free energy in the form of perpetual motion machines and other fantastical structures that bend the laws of physics to breaking point. We’d love them to be true but we have [Émilie du Châtelet] and her law of conservation of energy to thank for dashing those hopes. So when along comes a machine that appears to violate a fundamental Law of Physics, it’s reasonably met with skepticism. But the wind-powered vehicle built by [Rick Cavallaro] looks as though it might just achieve that which was previously thought impossible. It’s a machine that can move with the wind at a speed faster than the wind itself.
A fundamental law of sailing boats is that when they are sailing with the wind, i.e. in the same direction as the wind, they can’t sail faster than the wind itself. Sailing boats can go faster than the wind powering them by sailing across it at an angle to create lift from their sails, but this effect doesn’t work as the angle tends towards that of the wind.
The vehicle in the video below the break is a sleek and lightweight machine with a large propeller above it, which we are told is not the windmill power source we might imagine it to be. Instead it mimics the effect of a pair of sailing boats sailing across the wind in a spiral around a long cylinder, and thus becomes in effect a fan when turned by the motoin in the craft’s wheels. The drive comes from the wind working on the craft itself, and thus as can be seen from the motion of a streamer on its front, it can overtake the wind. It seems too good to be true at first sight but the explanation holds water. Now we want a ride too!
We’re not sure how many of you out there own a boat large enough to get its own integrated computer network, but it doesn’t really matter. Even if you can’t use this project personally, it’s impossible not to be impressed with the work [mgrouch] has put into the “Bareboat Necessities” project. From the construction of the hardware to the phenomenal documentation, there’s plenty that even landlubbers can learn from this project.
In its fully realized form, the onboard computer system includes several components that work together to provide a wealth of valuable information to the operator.
What [mgrouch] calls the “Boat Computer” contains a Raspberry Pi 4, a dAISy AIS receiver, an RTL-SDR, a GPS receiver, serial adapters, and the myriad of wires required to get them all talking to each other inside a weatherproof enclosure. As you might expect, this involves running all the connections through watertight panel mounts.
Combined with a suite of open source software tools, the “Boat Computer” is capable of interfacing with NMEA sensors and hardware, receive weather information directly from NOAA satellites, track ships, and of course plot your current position on a digital chart. The computer itself is designed to stay safely below deck, while the operator interacts with it through an Argonaut M7 waterproofed HDMI touch screen located in the cockpit.
For some people, that might be enough. But for those who want to do big, [mgrouch] further details the “Boat Gateway” device. This unit contains an LTE-equipped WiFi router running OpenWrt and all the external antennas required to turn the boat into a floating hotspot. Of course it also has RJ45 jacks to connect up to the other components of the onboard system, and it even includes an M5Stack Core with LAN module so it can display a select subset of sensor readings and navigational data.
As the Raspberry Pi in its various forms continues to flow into the wild by the thousands, it’s interesting to see its user base expand outside beyond the hacker communities. One group of people who’ve also started taking a liking to it is sailing enthusiasts. [James Conger] is one such sailor, and he built his own AIS enabled chart plotter for a fraction of the price of comparable commercial units.
Automatic Identification System (AIS) is a GPS tracking system that uses transponders to transmit a ship’s position data to other ships or receiver stations in an area. This is used for collision avoidance and by authorities (and hobbyists) to keep an eye on shipping traffic, and allow for stricken vessels to be found easily. [James]’ DIY chart plotter overlays the received AIS data over marine charts on a nice big display. A Raspberry Pi 3B+, AIS Receiver Hat, USB GPS dongle and a makes up the core of the system. The entire setup cost about $350. The Pi runs OpenCPN, an open source chart plotter and navigation software package that [John] says is rivals most commercial software. As most Pi users will know the SD card is often a weak link, so it’s probably worth having a backup SD card with all the software already installed just in case it fails during a voyage.
Sailboats have been traversing the Atlantic Ocean since before 1592, sailing through sunshine, wind, and rain. The one thing that they’ve all had in common has been a captain to pilot the ship across this vast watery expanse, at least until now. A company called Offshore Sensing has sailed an unmanned vessel all the way from Canada to Ireland.
The ship, called the Sailbuoy, attempted the journey last year as well but only made it about halfway before the mission was abandoned. This year, however, the voyage was finally completed, and this craft is officially the first unmanned ship to cross the Atlantic Ocean. The journey took about 80 days using sails and a small set of solar panels to drive the control electronics.
Using this technology, the company can investigate wave activity in specific areas of the ocean without having to send out a manned vessel to install a permanent buoy. The sailbuoy simply uses its autonomy to stay in a particular patch of ocean. There have been other missions that the sailbuoy has been tasked with as well, such as investigating the aftermath of the Deepwater Horizon oil spill in the Gulf of Mexico. With a reliable craft like this, it becomes much easier, safer, and less expensive to explore the ocean’s surface.
[Leo Sampson Goolden] is a boatbuilder and Sailor. He’s a prime example of a dwindling group of shipwrights who build sailing vessels the traditional way. In 2017, he was given the opportunity to buy Tally Ho, a Yacht built back in 1910. Once a proud ship, Tally Ho now sat as a shell under a shrink-wrap tarp. Her deck was rotted, her keel cracked. Any sane person would have moved on. Thankfully [Leo] is not quite sane, and began a quest to bring this history ship back to its former glory.
Tally Ho isn’t just an old boat. She is a 48-foot long gaff cutter yacht designed by the famous Albert Strange and built in Sussex, England. Tally Ho won the 1927 Fastnet Race (corrected time) when rough seas caused all but two boats to bow out.
To say [Leo] has his work cut out for him would be an understatement. Tally Ho lived a hard life, from racing to fishing. A complete restoration was needed. In fact, it would have been cheaper and easier to build a replica rather than restore the original. [Leo] wanted to save Tally Ho though, so he bought the boat for one dollar, and began to put all his time, effort, and funds into restoring her. This work includes carefully documenting each piece as it is removed.
Some of the tools and materials are traditional – such as chisels and red lead putty. But [Leo] is using power tools as well, including a custom-built chainsaw mount for shaping the keel. His videos are entertaining and illustrate many techniques of boat building. Wherever possible, [Leo] adds captions to explain the meanings of boat building terms, as well as explains the different terms used in England and the USA. In the latest video, you can watch along as [Leo] creates a Dutchman to fill in a knot in the keel. Can check that out in the video after the break.
For those not familiar with sailing, it might seem like an obsolete way to get around on the water. This isn’t 1492 anymore, and it’s pretty easy to go out and get a boat with a motor to get where you need to go. Sailboats, however, are still one of the most efficient ways to travel. There are essentially no fuel costs, and maintenance on them is often easier than on a boat with an engine. Not to mention the fun involved in flying a hull on a catamaran. Anyway, if you’re [gwilken], you can bring your sailboat even further into modern times by building your own sensor array for it.
The ultimate goal of this project was to get all gauges and sensors reporting data to an iPad, rather than to random gauge clusters around the ship. This includes environmental conditions, speed, and motor status (most larger sailboats have a motor for getting around the marina). A Raspberry Pi ties it all together, including a GPS antenna for monitoring location. [gwilken] also includes a WiFi antenna and a cell antenna for maintaining a network connection for reporting all of this information. With this connectivity, he can also control some functions of the boat as well.
[gwilken] made the decision to ditch the conventional gas motor for a more energy-efficient electric motor. This also has the perk of being essentially maintenance-free, and can even charge his battery in regen mode while his boat is under sail. The sailboat is now fully equipped for the 21st century, in a similar way to another boat’s gauge cluster that was recently featured.