About Kimball Livingston

Kimball Livingston is a former senior editor, and now editor-at-large, for SAIL. His work also has appeared in Sailing World, Cruising World, Soundings, and more. Over three years, Kimball sailed the Centennial Transpacific, Centennial Newport-Bermuda, and 100th Chicago-Mac. His blog posts appear courtesy of his website www.KimballLivingston.com.

Kimball Livingston’s BLUE PLANET TIMES 2010-08-09 15:55:00

Leslie Greenhalgh, TEAMORIGIN

So Keith Mills (Sir Keith) has a field day with the “1851 Cup” and about five minutes after his Team Origin boys win their match against BMW Oracle he gives an interview to the Times on Sunday, claiming that the only possible motive for choosing multihulls for America’s Cup 34 would be to give the Defender an advantage. But, the last time I checked, the America’s Cup team with the most background, depth of experience, and longterm success in multihulls was Alinghi (despite losing a couple of races last February). So, by this logic, is Ernesto Bertarelli called back to center stage?

The jungle drums are all beating multihull, multihull, and right now the top BMW Oracle players are in San Francisco for further talks with the City and the Port about The Venue.

Dare we hope they might settle this sooner rather than later?

In Cowes for their private match, the Team Origin folks had a lot of face time with BMW Oracle Racing CEO Russell Coutts, and he must have given them cause to believe that the Defender is leaning toward multihulls as the platform of choice. They made clear they don’t like it. Mills first made his mark in advertising and marketing, so we know he’s not just winging it when he has his lieutenants firing salvos, though I note they were not exactly on the same page.

Team Origin CEO Grant (ex-Alinghi) Simmer: “Oracle are two years ahead in that technology, so the rest of us would have no chance. We believe that multihulls is the way it’s going to go, but there’s no challenger that wants to do multihulls.”

Skipper and Olympic gold medalist Ben Ainslie: “If we have to do multihulls, then we’ll have to do it, but we’d be playing catch-up.”

Mills: ” There’s no point in spending millions of pounds on a challenge that’s unwinnable.”


Meanwhile, I hope the Oracle folks stick to their knitting and don’t look outside. The marine layer is 2,600 feet deep.That’s not the postcard view of San Francisco Bay, but they’re selling plenty of sweatshirts at Fisherman’s Wharf this week.

A Full Head of Steam

Today we’re at Steam Up, a model yacht gathering that is exactly what the name tells you. It’s all about steam. Real steam engines, in miniature.

What would inspire a former military pilot, now retired from a career in finance, to spend three years building something like this . . .

Well, the inspiration would come from something like this, the original S.S. Tahoe, which Alan Zulberti happens to believe is one of the most beautiful vessels ever . . .

The original S.S. Tahoe was launched in 1896 with all the luxuries and the latest advances, including electric lights. Having outlived her time, she was mis-scuttled in 1940. Yep, mis-scuttled. The plan was to sink her in relatively shallow water, where she would be an attraction for the patrons of glass-bottomed boats, peering into the famously clear waters of Lake Tahoe. Instead she slipped away to the depths.

But in miniature, the S.S. Tahoe has returned . . .

It takes about ten minutes for the S.S. Tahoe’s miniature boilers to build up a full head of steam, and I’m not going to even attempt to describe the lavishness of the riveted copper hull, but Alan’s other big little project was PT-588, with operational armaments, rocket launchers, twin-screw torpedoes that top 60 mph and more. You can read about that model in all its gonzo glorious detail right here.

The Frequency Control Board is for assigning and separating wavelengths . . .

Some people, of course, find it impossible to pass without stopping for a look, but that’s part of the idea . . .

Spreckels Lake, Golden Gate Park. August 8, 2010.
An annual event of the San Francisco Model Yacht Club.
One final toot . . .

Ducks Have Right of Way

Moody ducks, but that’s not what we’re talking about. Photo by Dave Kneale

There is more than one way to approach the game of yacht racing.

I figure every one of them has value.

I figure every one of them matters.

You can go aspirational. It’s about climbing the ladder. Winning an Olympic medal, perhaps, or winning a class championship, or winning the season on your local pond, or just getting through a regatta with top-half finishes in every race. You get to define “winning.” That belongs to you. But you’d better be keeping a journal, taking notes, following the example of Dennis Conner and leaving yourself “no excuse to lose.” Whether you’re sitting on carbon fiber or plywood, twitching a tiller or trimming a sheet—or hiking hard, hoping to eventually get to move up to being a trimmer—it is a fine thing to be obsessed with sailboat racing.

Needless to say, Antoine Screve and James Moody, two young Americans who just won the 29er sailing at the Volvo Youth Sailing ISAF Worlds in Istanbul, are living, sleeping, waking in that mode. That would be Screve and Moody in the picture at the top of this story.

But you could also say to yourself, it’s a lovely day on the water, and it’s more fun to be out here if we’re playing a game, and while we play the game we try very hard, but we know it’s all horsefeathers, so who cares how it comes out.

Take away either mode, and as a sport, we lose.

I got to thinking about the difference while I watched X-Class models race on Spreckels Lake, Golden Gate Park. This is the only place in the USA with a fully-commissioned free-sail fleet. Meaning, racing in the old way, without radio control, and the differences between free-sail and radio control are huge.

Radio-controlled competition uses Appendix E of the Racing Rules of Sailing, which makes only a few changes to the rest of the book. I’ve watched people get pretty wound up in the middle of a models race, same as they do in what the model sailors call “people boats.”

Passion rules, but ducks have right of way.

(btw, a few years ago I wrote a feature, Pond Life, for SAIL Magazine, and it drew the biggest response I’ve ever had to a magazine story. This model stuff is serious. Further btw, 2010 is the 40th anniversary of the American Model Yachting Association. Happy birthday.)

Free-sail competition deserves a bit of explanation.

Spreckels Lake was purpose-built in 1903, with the north shore of the lake running parallel to the seabreeze. The same reliable, westerly seabreeze that gives San Francisco Bay its sporting character. There is just a minor curvature to the north shore, to please the eye, and having a shoreline parallel to the prevailing wind is what makes free-sailing here a pleasure. Races start downwind, go the length of the lake, and return. The art and science—it takes both—is to tune your boat slightly out of balance, so that it will sail itself out into the lake, far enough but not too far, lose balance, turn, and sail back to the shore.

Your job, downwind and back, is to walk along and meet your boat. You carry a 5-foot, 4-inch stick, and you are allowed to touch the bow once, to turn the boat back into the lake, and your are allowed one course-correction touch to the stern. Two boats race together. Anything more would be mayhem, but there usually are multiple races under way.

At the bottom of the course you take your boat in hand and reset the sails to tack upwind. Each race is thus two races in one. If you split, the upwind-leg winner takes the tie break.

Occasionally you see a boat that isn’t set up quite right, sail off toward oblivion.

Occasionally you see a grown man run.

And make adjustments.

What I’ve never seen is a free-sail competitor yelling. The yachts are each a thing of beauty, restful to the senses, and yes, some boats are faster than others, and some skippers are more skilled than others, and fast boats and smart skippers are likely to come up winners.


That wonderful, celebrated seabreeze that blows in as reliably as ever is all chopped up these days by the forest that has grown up in Golden Gate Park since the lake was created. Think random puffs. Random shifts. A fickle finger of fate always ready to stick it to you.

You must be at peace with the fundamental absurdity of the game.

May it always be so, and so lovely.

The San Francisco Model Yacht Club dates to 1898 and these days occupies a WPA-built clubhouse at Spreckels Lake where the members not only preserve the treasures of the past but also keep them trim and active.


The powerboat side of the Model Yacht Club gets the south shore of the lake for their fun and games, and the club’s second annual Steam Up on Sunday, August 8 from 1000 to 1600 will be a delight. If you’ve never seen a steam-powered six-footer, exquisitely detailed and puffing proudly along, your karma is not complete.

Full disclosure: Dress warmly. The marine layer is 2,000 feet thick.

Spreckels Lake is on the western, seaward side of San Francisco, and I happen to live on the western side of San Francisco, and just at the moment, in my sentient, front-of-computer mode, I’m wearing two layers of fleece over a wool sweater. You photographers will have noticed there were no, ah, highlights in my photographs of the X-Class.


The one hundredth birthday of what we believe to be the oldest still-active boat in Southern California was duly celebrated last weekend at Los Angeles Yacht Club’s Catalina cove, Howland’s Landing.

Friends and family turned out . . .

Owners Bill Wright and Deborah Bird were in fine form . . .

Among the many well wishers was George Griffith—the man who long ago envisioned the Cal 40 and made it a reality, and changed the course of boat design—dropping by to pay his respects . . .

It is special to see one boat in one family for 99 of its first 100 years. We told the Siwash story in this earlier post.

My thanks for the photographs go to Fin Beven and to Walter Savage Wright’s descendant, Heidi Fuller. It was Walter Savage Wright who bought the boat in 1911, for his son, and set Siwash on her way. He couldn’t possibly have imagined.

Downwind Noir: The Record


“Because it wasn’t there.” Sir Edmund Hillary

All photos by Kimball Livingston

Oops, I guess that’s a slight misquote of Hillary. But how else to introduce Rick Cavallaro, who invented an unproblem and then solved it—to the consternation of many an internet flamer—and opened up new possibilities in wind energy extraction, all while proving that, yes, it absolutely is possible to build a machine that will go dead downwind faster than the wind, using only the wind.

Then to be told, “It might work in practice, but it will never work in theory.”

This was the team setting up . . .

And this is the thing in action . . .

There might yet be someone arguing that the concept in question can’t work in theory or in practice. It can be hard to let go of words such as these from a leading figure (quoted in full, recanting, at the end of this story) who declared, “These loonies were pursuing a pointless goal, doomed to failure . . . I dismissed it as utterly impossible.”

A certain Nobel laureate was less graphic but no less scathing.

But that was then, and this is now, and the machine created by the “loonies” of the Thin Air Designs team has busted 50 mph and gone three times faster than the wind, dead downwind. Using only the wind. More than once. I’m telling you.

Given the tight strictures imposed for an official record, the run submitted for ratification was “only” 2.8 X. This is now official, certified by NALSA, the North American Land Sailing Association, at 27.7 mph in a wind of 10 mph.

In nearly 20 runs over two days, in the high heat of the high desert, while thin snow still veined distant mountaintops, every run exceeded 2 X, and if things work out over the next few weeks, these guys are going for an official 3 X.

Through a series of unlikely events I found myself named as one of two NALSA observers for all of Cavallaro’s officially-timed runs, and I’m believing the same principle would also work on that more complicated interface we call water, should anyone be motivated, though that seems even more unlikely than the story I’m relating here. I mean, if Don Quixote tilted at windmills . . .

How could I resist a project labeled DDWFTTW?

At El Mirage Dry Lake in the Mojave Desert, over the July 4 weekend, I watched this pretty agricultural, mixed-technology contraption top 50 mph more than once in winds that never got out of the teens. It doesn’t begin to tap the potential of the concept.

Actually, it does begin. Certain elements were machined to a fare-thee-well; others were merely good enough to test the concept on the cheap. When early trials last spring exceeded expectations, aerodynamic fairings were carved out of foam. Velcro holds them in place. The driver sits in a web of netting, inches above the desert floor. Yes, that’s a bicycle tire . . .

But the machined parts are no joke. At speed, the craft is developing 500-700 ft lbs of torque on the prop shaft—close to the torque output of a supercharged Corvette V8 . . .

The left axle is longer (a wider stance) to account for prop torque . .

And the propeller diameter is 17.5 feet. Notice an inkie-winkie delamination on the blade of the prop . . .

Yes, prop. There isn’t a sail or even a wing on what was known as the BUFC, the Big Ugly #&*! Cart, until Joby Energy and Google put some sponsorship behind it. Now, with a nod to landsailing speed record holder Greenbird, Thin Air Design’s BUFC thingamajig is known as Blackbird.

No sail, no wing, but, aerodynamically speaking, there is no fundamental difference between the angles of a spinning propeller blade and the angles of a sail that is being tacked downwind, hot.

Sailors know that an ice-boat, for example, can tack downwind, building apparent, and beat a piece of paper blowing in the wind. What Cavallaro can do is beat a piece of paper, big time, right down the paper’s track.

What did the wind know, and when did it know it?

Believe me, I’d have found it hard to wrap my mind around this if my introduction to Rick Cavallaro had come from anybody other than Stan Honey. But here came Stan, with Rick in tow, and also JB Borton (chief engineer, machinist, and project bodhisattva). Stan, most readers will know, is arguably the world’s greatest ocean navigator, and he was a founder of Sportvision, the revolutionary software company that, among so many things in broadcast sports, “paints” football’s yellow first-down line, shows the path of a pitch in baseball, and tracks telemetry for NASCAR . Stan is also now on the case of developing better America’s Cup broadcasting for BMW Oracle Racing. Rick Cavallaro is the chief scientist at Sportvision. JB Borton is a world champion in soaring aircraft and the director of manufacturing for Sportvision. Rick is a kitesailor, and if you check the t-shirt you can guess what these guys do in their other lives. That’s JB on the left . . .

Stan introduced me to this pair at a talk given by the fastest sailor in the world, Richard Jenkins. In 2009, in a very-different landsailer of his own, Jenkins fulfilled a ten-year quest by hitting a record 126.2 mph at Ivanpah Dry Lake in the Mojave Desert. Of course Stan, Rick and JB wanted to lend an ear. Jenkins’ talk to a lunch group on the San Francisco cityfront was very nearly his only public outing since becoming a world record holder.

Bob Dill, left, former speed record holder, and Richard Jenkins

The DDWFTTW project was different, but.

Three times windspeed is quite an interesting multiple, the more so when you consider that the goal was a “mere” double, and most people thought that was impossible. I mean, how can you use the wind to outrace it?

On a different level of thinking, however, Jenkins’ wing-powered Greenbird was constantly fighting sideslip with fat tires and a wide track en route to an absolute speed record. Going DDW with the goal of “simply” outrunning the wind eliminates that problem while, admittedly, opening others.

Borton, left, and Dill check the breeze. Or we could caption this—Elvis, if you’re out there . . .


I wish I could explain, but it’s best to turn the job over to Cavallaro, who notes that ice-boats and land-yachts routinely tack downwind at a net gain. That is, you could release a balloon and race it downwind, and win.

So a guy with a brain-teaser fetish might naturally (or unnaturally) fall to wondering how to go directly downwind faster than the wind. At fasterthanthewind.org you can read:

“With a bit of thought it occurred that one could reproduce the aerodynamics and physical constraints of the land-yacht by simply having the sail follow a continuous downwind tack, but wind that tack into a spiral. Two such sails would simply form a propeller. By gearing this propeller to a set of wheels, you could constrain it to follow the same downwind path that the sail of the land-yacht follows, but on a steady downwind tack. So it seemed such a vehicle could in theory be constructed quite simply.

“Sometime around 2004, Rick posted this brainteaser on an internet forum expecting to get some right answers, some wrong answers, and a few exclamations of “wow,that’s pretty cool”. What he got was a stink that ran across thousands of pages over countless internet forums. Many people (including some aero and physics PhD’s and professors) were certain it could not be done. Absolutely certain. More than a few were insulting of Rick’s intelligence and sanity.”

Several of them have had to adjust.

Myself, I tell it this way.

My job as Observer #2 was to stand behind the vehicle, sight the wind, share information via radio and arrive at a moment when Chief Observer Bob Dill—a past president of NALSA and until a year ago the fastest sailor in the world—would decide that we had a proper downwind setup. Dill was stationed at the bottom of the course. Wind speed, wind direction, vehicle speed and vehicle direction were each closely calibrated—and recorded—at multiple locations, mobile and stationary. The breeze at El Mirage was up and down, and oscillating. The goal was to select a stable patch of breeze and run in that. When Dill and I agreed that we had what we wanted, we would give the team a go. Often, I jumped aboard a chase vehicle to observe the entire run. For once, I didn’t have to worry about salt water on my camera, but I’m still clearing the dust . . .

Some runs began from a dead stop, accelerating as the breeze moved the vehicle, but NALSA rules have always permitted a hand push, and JB usually put his back to it. Frankly, I don’t believe that pushing affected the final numbers on any of the runs. The cart will get itself to wind speed, push or no, and then it goes to work. But we did not correct for push/no-push.

It is important to understand that the propeller and the rear wheels are directly linked via chain drive.

Which also was the weak link. The best multiples were available in true wind speeds of 10-12 mph. Running in winds in the mid-teens got the machinery to the edge of its built-capability. The BUFC was still accelerating on its fastest run when the chain broke at 51 mph.

Rick studies the results of a run . . .

So we would launch, and the yarns on the Blackbird would be blowing forward, downwind.

Then, trust me, some combination of factors—windage, the propeller—would eventually get the thing going at the speed of the wind. The telltale yarns that had blown forward would go random; up, down, out, about. This is the point where, intuitively, the action ends, except—with the propeller and the wheels linked, the wheels are now driving the propeller, and the propeller is turning through what we have agreed is zero mph of apparent wind. Dead air. But a propeller in motion has no trouble chewing into dead air and putting it to work for horsepower and speed. This is when the thing really begins to work. Voila. The telltale yarns blow back as the darned thing takes off, living up to JB’s quip that the point of the project is, “If my hat blows off, I can catch it.”

But, now that this has been done, we can imagine the possibility of enhanced energy extraction, can we not?

So there we were, unshaved but showered-down and burgering-down under the neon at some diner-dive in or near beautiful Palmdale, California and feeling pretty good. It wasn’t my project. I was there as a journalist double-billed with the title of Official Observer #2, and it wasn’t my job to create a success, but I would have been disappointed if the thing had been a fiasco, you bet. I had other options for my July 4 weekend, 2010. The same could be said for Bob Dill, who deserves to be recognized beyond his nexus of landsailing and iceboating. Beyond the fact that he once held the sailing speed record (on land) at 116 mph, this is one constructive, imaginative, generous s.o.b. Last spring he invited the Thin Air Designs team to NALSA’s “America’s Cup” event at Ivanpah Dry Lake, and what he saw convinced him to become a supporter, rather in the way that, while Richard Jenkins was working his booty off to take away Bob Dill’s speed record, Dill aided and abetted at every turn. This is not a story about Bob Dill, but while we’re not on the subject, in all honesty, I think you ought to know.

We enjoyed, shall we say, a frank and wide-ranging conversation, stimulated by garlic fries that you might not easily find beyond the culinary inspirations of Palmdale.

Or Lancaster.

Or wherever we were. Somewhere in the conversation, Steve Morris—he’s the team aerodynamicist who designed the propeller—mused, “The truth is, there are a lot of crazy wind energy projects out there.”

And Rick declared, “That’s what we bring to the table. We’re 20 percent less crazy.”

The Thin Air Designs team . . .

Steve Morris, Chris Fields, JB Borton, and Rick Cavallaro


It’s been probably five years since I met Richard Jenkins at Ivanpah Dry Lake, 40 miles outside of Las Vegas. He was deep into his determined march toward the landsailing speed record, but years away from fulfillment. These days he’s into, ah, kiteboats on San Francisco Bay and, in the winter, chasing a speed record on ice. But just as Rick, JB, and Stan once showed up for Richard’s talk at St. Francis Yacht Club about hitting 126.2 mph at Ivanpah, Jenkins showed up at El Mirage to watch the Blackbird run. We could see his rented Ford blowing up a cloud of dust as he raced toward us across the lake bed. He stepped out of the car and announced, “You’d think that with all the years I’ve spent in the desert, I’d have known to bring a hat.”

Jenkins stayed for most of the day and observed most of the runs. Until he wrote a “guest editorial” on the project blog, Rick says, “I had no idea he was such a raging skeptic.” But Richard Jenkins is a reformed skeptic. Here is what he shot with his video camera. I like it because it was not shot by a member of the team, and the vehicle self-starts. Looking closely in full-screen mode, I have no problem seeing the telltales change as the craft accelerates through windspeed.

Here is what the Richard Jenkins wrote about the experience.

“One night, I was happily drinking my beer and tending to my inbox of endless, boring emails when Lester, my landsailing buddy, texted me a link to fasterthanthewind.org. Lester knows a lot, and if he says this needs my attention, then it gets it. I am not sure if it was how many beers I had had, or simply the inane nature of the quest, but I laughed enough to email all my friends to share the absurdity of their mission. My heart is split between belittling idiots, and saluting eccentrics, and this downwind quest lay somewhere in the middle. These loonies were pursuing a pointless goal, doomed to failure, but there was genuine merit in the myth and their enthusiasm.

I dismissed it as utterly impossible. Traveling through zero apparent wind, with no stored power? Impossible. Why would you even attempt it? (Though I’m no stranger to that question myself!) But had I been asked to bet at that moment, I would have just lost a lot of money.

A few months later I actually met the idiots in question and, to my surprise and concern, we not only have a few mutual friends, but they seemed to be technically credible. But, everyone makes mistakes, and I let them off as decent people with a blinkered view of fundamentally flawed engineering….

A few months later they were claiming success, and if it was not for another great friend, Bob Dill, advising that they were actually correct, I would have discarded their claim as an April fool. I thought about the possibility that I was wrong, and then considered that as Bob was getting on and had a bit of a shake with his stopwatch finger; maybe it was he who was mistaken. There was, however, a growing momentum of technical people (who should have known better), saying that these idiots have actually proven that it is possible to travel faster than the wind going directly down wind.

Not content, I had to witness this myself. When I heard it was on for the official record at El Mirage, I jumped on a plane and went to check it out.

The video speaks for itself. These guys are not idiots, but sincere, genuine, technical people who took a myth and made it real. It works. It starts from rest, trundles to true wind speed, then powers to a multiple of about 3 times the true wind speed.

To all fellow skeptics, start baking that humble pie, or eat your hat. Your choice.”

Richard Jenkins


As the sun sinks in the west, we are riding the shoulders of giants . . .

Photos by Kimball Livingston


And what rough beast, it’s hour come ’round at last, slouches toward Bethlehem to be born? All photos by Kimball Livingston

Below, friends, is a document that I want on record at the Blue Planet Times. I’ll be referring to it on Monday, when I write the story of the first vehicle ever to go
Dead Down Wind Faster Than The Wind.

Using only the wind.

This is the opening salvo in my account of the DDWFTTW project, and this is the highly-technical submission made to the Board of NALSA, the North American Land Sailing Association, requesting that it ratify a multiple of 2.8 times the speed of the wind, dead downwind, using only the wind.

That record has now been ratified.

I came into this story as official observer number two, which is how I came to make an excursion recently . . .

Down half the length of California from San Francisco to the Mojave Desert . . .

Past the windfarm . . .

Past the Pleasant Valley State Prison (?) and past not one but two grass fires in the Tehachapis . . .

For a quick survey of El Mirage Dry Lake with the Thin Air Designs team . . .

Steve Morris, Chris Fields, JB Borton, and Rick Cavallaro with the thing

And then to a restful slumber, freeway side . . .

And then back to the dry lake and down to business.

Next, a clear look at the machine itself, and a much-clearer account of what I’m talking about: The mission, the action, the success. Below, the promised document. Good luck with it. I’ll be more anecdotal, next time out.

Report for the Submission of Data
Supporting a World Record Run in the Category Dead Downwind Vehicle

Prepared by Rick Cavallaro
12 July 2010

On July 2nd and 3rd of 2010, the Thin Air Designs team made a number of runs with their wind powered vehicle, the Blackbird, on the El Mirage dry lake bed in Southern California. This was done in a bid to establish the first world record in the category of wind powered vehicles capable of exceeding the wind speed steady state – directly downwind. This report will present the data logged in accordance with the rules for this new category as set forth by the North American Land Sailing Association (NALSA). On hand from Thin Air Designs were:

Rick Cavallaro – Vehicle designer, builder, and driver
John Borton – Vehicle designer and builder
Steve Morris – Aerodynamics consultant
Chris Fields – SJSU student contributor

On hand representing NALSA as official observers were:

Bob Dill – Member of NALSA board of directors
Kimball Livingston – An editor of SAIL, deputized by Mr. Dill

Others on site included Richard Jenkins (world land speed sailing record holder), four engineers representing Joby Energy (primary sponsor of the Blackbird), and several others who had been following the project.

Vehicle Description

The Blackbird is a vehicle designed and built with the sole purpose of traveling directly downwind, faster than the wind, powered only by the wind, steady state. It has a tricycle configuration and a 17.5’ diameter propeller on the top of a set of pylons over the vehicle’s rear axle. The propeller is connected to the rear axle through a simple chain-drive transmission and ratchets. This configuration permits the wheels to turn the propeller via the fixed ratio transmission, while allowing the prop to freewheel during braking. The prop pitch can be controlled by the pilot “on the fly”. By design, such a configuration cannot be accelerated through the use of stored energy/momentum. The vehicle makes no use of any controls or actuators other than those operated directly by the pilot with human power.

Analysis demonstrating that the vehicle is capable of DDWFTTW

In order to run in this NALSA category it must be demonstrated that the vehicle is capable of going directly downwind, faster than the wind, powered only by the wind, steady state. While this has been a hotly debated topic on the internet, the principle has been demonstrated many times with working models and has been analyzed both by the ThinAir Designs team as well as by noted aerodynamicist Mark Drela. See Drela Power Analysis and Drela DDWFTTW Analysis.

The following case study will demonstrate the principle in simple terms:

Consider a cart with an electric generator driven by the rear axle and a propeller driven by an electric motor. We’ll assume the following reasonable set of parameters:

Electric generator efficiency: 85%
Electric motor efficiency: 85%
Propeller efficiency: 85%
Coefficient of rolling resistance: 0.02
Vehicle gross weight: 650 lbs
Coefficient of aerodynamic drag: 0.3
Projected frontal area: 20 sq-ft

For the purpose of this analysis we won’t consider the issue of accelerating to speed, but rather the cart’s ability to maintain faster-than-the-wind speed and further accelerate from that point. Thus we’ll tow the vehicle up to a speed of 20 mph in a 15 mph tail-wind and then let it loose. In this situation the vehicle will experience a relative head-wind of 5 mph. We’ll adjust the generator output such that it produces 20 lbs of retarding force at the wheels. This tells us the wheels will be putting power into the generator at a rate of 20 mph x 20 lbs (400 mph-lbs). But the generator will only produce 340 mph-lbs due to its 85% efficiency.

We deliver that power to the electric motor. But we get only 289 mph-lbs at the motor’s shaft due to the motor’s 85% efficiency. This power is working to spin the propeller, but the propeller does only 245 mph-lbs of work on the air due to its 85% efficiency. Given the vehicle’s relative airspeed of 5 mph, we can see that the prop will be producing 49 lbs of thrust.

Given our vehicle gross weight of 650 lbs and coefficient of rolling resistance of 0.02, we can calculate that we’ll lose 13 lbs of thrust to rolling resistance. We lose another 20 lbs at the wheels due to the retarding force caused by the electric generator. This leaves us with an excess of 16 lbs (49-13-20).

Finally, we have to consider the aerodynamic drag we experience in this state:

Aero_drag = Drag_coeff * frontal_area * ½ * rho * Vel * Vel

In which rho is air density and vel is the relative air velocity experienced by the vehicle.

Aero_drag = 0.3 * 20 * ½ * 0.002329 * 7.333 * 7.333 = 0.376 lbs

Where 0.002329 is the air density in slugs/ft^3 and 7.333 is our velocity in ft/sec.

Subtracting our aero drag of 0.376 lbs from our excess thrust of 16 lbs, gives us a remaining excess thrust of 15.6 lbs. This shows that the vehicle will continue to accelerate from this state.

The simple explanation is that the vehicle acts as a lever between two media (the ground and the air). Like any lever we can trade a small force over a large distance for a larger force over a smaller distance. This is how we get more thrust from the prop than we create drag at the wheels (since the wheels are moving over the ground faster than the prop is moving through the air –due to the tailwind).

Proof that the vehicle performs best Dead Downwind

As can readily be seen from the above analysis, the vehicle performance is driven significantly by the prop efficiency. This of course is primarily a function of the Lift/Drag ratio of the propeller airfoil at its operating angle of attack. The propeller on the Blackbird is based on the NACA 6412 airfoil which has it’s maximum L/D at 4.0 degrees, and has a twist such that the airfoil at each spanwise station is presented at that angle of attack (AOA). When the relative flow is aligned with the propeller axis, that AOA can be maintained at all spanwise stations throughout the complete rotation. Any cross-wind component from the right will cause the AOA for the top blade to increase while the angle of attack of the bottom blade is decreased. A cross wind component from the left will have the same effect in the opposite direction. In both cases the AOA will depart from it’s optimum value to varying degrees over the full rotation of the prop in this case – reducing the propeller performance – and thus the overall performance of the cart. The cart employs no other aerodynamic surfaces that can take advantage of a cross-wind component.

Analysis of 10 second run submitted

It is easiest to review the following data with the use of the “AnaGraph” analytical plotting program provided – but all data is in ASCII format and is described in detail below. The following can be seen by opening “avg_speed_ratio.agr” in AnaGraph.

The subject run begins from a dead stop at 588959.4 seconds (as measured in the DAPS format and used throughout). The downwind cart is pushed by hand (by JB) and released at 588977.0 at a ground speed of 11 mph. From this point the DW cart accelerates monotonically, by wind power alone, up to and through the 10 second measurement period from 589060.8 to 589070.8.

During this period, the DW cart achieved a 10-second average speed of 27.665 mph while the wind had a 10-second average speed of 10.01 mph.

During this period the DW cart maintained a 10-second averaged heading within less than 5 degrees of the 10-second average of the true wind direction.

Over this same period, the DW cart averaged a 2.77 multiple of true wind speed, while it’s absolute speed increased from 26.84 mph to 28.81 mph.

Contents of “conflated5.txt” by column

1 time1 Seconds (from beginning of week I believe)
2 cv_lon Chase veh. longitude (deg)
3 cv_lat Chase veh. latitude (deg)
4 cv_gps_speed Chase veh. gps speed (mph)
5 cv_gps_heading Chase veh. gps heading (deg; 0.0 is east, 90 is north)
6 cv_rel_windspeed Chase veh. relative windspeed (mph)
7 cv_rel_wind_dir Chase veh. relative wind direction (positive to the left as with magnetic heading – but intentionally offset to avoid the null – see readme.txt for val)
8 dw_lon Downwind cart longitude (deg)
9 dw_lat Downwind cart latitude (deg)
10 dw_gps_speed Downwind cart speed (mph)
11 dw_gps_heading Downwind cart heading (deg; 0.0 is east, 90 is north)
12 true_wind_speed True wind speed measured at chase vehicle and computed from chase vehicle relative wind velocity and GPS velocity (mph)
13 true_wind_direction True wind direction measured at chase vehicle and computed from chase vehicle relative wind velocity and GPS velocity (deg; 0.0 is east, 90 is north)
14 dw_gps_speed_10_pos 10-sec avg DW cart speed (computed from GPS position at +/- 5 seconds
15 dw_gps_speed_10_vel 10-sec avg DW cart speed (computed from GPS speed and heading)
16 dw_gps_hdng_10_pos 10-sec avg DW cart heading (computed from GPS position at +/- 5 seconds
17 dw_gps_hdng_10_vel 10-sec avg DW cart heading (computed by averaging GPS speeds and headings)
18 avg_wind_speed 10-sec avg true wind speed measured from chase vehicle (JB’s car)
19 avg_wind_dir 10-sec avg true wind direction measured from chase vehicle (JB’s car)
20 avg_speed_ratio (10-sec avg cart speed) / (10-sec avg wind speed)

DAPS WindLogFile* content/format

1) Time in seconds (from the beginning of the week I believe). Most of these files have several lines at the beginning with very low numbers for time. This is what happens before the GPS begins to lock. I simply discard these lines completely – there’s nothing interesting on them.
2) Lon in decimal degrees
3) Lat in decimal degrees
4) GPS Speed in mph
5) GPS Heading in degrees (this is NOT in the normal way you’re used to in NMEA strings. This is done in the more typically mathematical coordinates. 0 is a heading of due east. 90 is due north. 180 is due west, and 270 is due south. So it has a 90 degree offset relative to NMEA strings, and an opposite sign.
6) Windspeed in mph (measured by anemometer on vehicle – not true wind speed)
7) Wind Direction in degrees (in the more typical NMEA sense). NOTE however that there is an offset for each sensor given in the readme file. These sensors were intentionally rotated so that the NULL was not aligned with the nominal wind direction to be expected during operation. Measured by anemometer on vehicle – not true wind speed)
8) Lon standard deviation (in degrees – I think)
9) Lat standard deviation (in degrees – I think)
10) Number satellites in solution
11) HDOP Horizontal dilution of precision.
11)VDOP Vertical dilution of precision.
I think VDOP may always zero in these files and is not valid

“dist.txt” content/format

1) Time in seconds (DAPS format)
2) Distance (in feet) between JB’s chase vehicle and Steve’s stationary vehicle
3) Distance (in feet) between DW cart and Steve’s stationary vehicle
4) Distance (in feet) between DW cart and chase vehicle

Legend for “dist.agr” plot

Red: Distance between chase vehicle and Steve’s stationary vehicle
Green: Distance between DW cart and Steve’s stationary vehicle
Blue: Distance between DW cart and chase vehicle
Black: True wind speed at chase vehicle
Grey: wind speed at Steve’s car

Legend for “avg_speed_ratio.agr” plot

Red: 10-sec avg DW cart speed (mph)
Green: speed ratio (10_sec_avg_cart_speed / 10_sec_avg_wind_speed)
Blue: 10-sec avg cart heading (0 is east, 90 is north)
Black: 10-sec avg wind direction (TO direction; 0 is east, 90 is north)

NOTES for 7-3-2010:

Offset between GPS time measured by Dill receivers and DAPS units

589525.5 DAPS = 71111 Dill gives: 518414.5 offset


Dill-5, Dill-7, and Dill-9 are the self-contained logging GPS receivers placed on the downwind cart by Bob Dill

Steve’s car (stationary for all runs today)
DAPS Unit #28
Wind vane with tail straight forward: 92.8 92.8 92.8

Ground station
(was Chris’s car on 7-2-2010 – stationary for all runs on 7-3-2010)
DAPS Unit #62
Wind vane with tail straight forward: 87.2 90.0 88.6 91.4

JB’s car
DAPS Unit #7 (active chase-vehicle for all runs on 7-3-2010)
Wind vane with tail straight forward: 264.4 264.4 261.6 263.0 264.4
Avg: 263.56

Steve’s car arrived at: -117.61553071, 34.65265540
At DAPS time: 590334
At a heading of 239.5 deg (DAPS format)

Every Hundred Years

Siwash at Cueva Valdez

Once she held the Around Catalina record, now she’s 100 years old and it’s time to party. So if you hear a bit of shouting this Saturday, coming from the direction of Howland’s Landing, Catalina, the action is probably on the deck of the redoubtable Siwash, a piece of floating history.

Is there another Southern California raceboat still floating, still active, that’s older? Much less a boat that has been in one family for a century?

There’s no knowing what the builder, Charlie Fulton, intended to call the 47-footer he built in Wilmington, on the shores of Los Angeles Harbor. What’s certain is that this high school kid, Howard Walter Wright, hung around every day, lusting after the boat as it came together frame by frame. And come time to launch, some disgruntled yard worker chalked the world Siwash on the transom—it was a not quite gentle dig at Fulton, who had some Indian blood—and Fulton decided to paint the name on and let it stick. (Go ahead, try to insult me.)

Siwash was Fulton’s boat, but only for a while. The lucky young Wright had earlier been gifted with a 28-footer, but his persistent mooning over Siwash was rewarded when his father bought the big boat for him as a high school graduation present.

Howard Walter Wright, left, aboard his first love, with his father, Walter Savage Wright, on the tiller; en route to Mexico in 1913

“Los Angeles was a little town in 1910,” says Bill Wright, who was a graduate student at Scripps in 1982, when he bought the boat for a dollar from his brother, Howard, who in the 1970s had bought it for a dollar from their father, who had inherited it from his father in 1959.

In 1912, Siwash won the Around Catalina Island race with Howard Walter Wright at the helm and a crew of Stanford fraternity men. The family story has it that she set a record that stood for some 25 years. According to Stanford lore, Siwash sailed the course in 12 hours, 14 minutes.

“We should have gone around in ten,” her skipper said, “but the boys got terribly seasick up by the west end of the Island.”

“Granddad sailed the boat around quite a bit,” Wright says. “It went as far south as Turtle Bay and Scammon’s Lagoon, and it was all over the Channel Islands. Around 1939, granddad had the new rig put in—the rig we have now—which is a gaff yawl setup designed by an up and coming fellow named Olin Stephens.”

There was, btw, no engine.

Howard Walter Wright on Santa Cruz Island at the end of a successful boar hunt

Photos courtesy of the Wright family.

Present owner Bill allows, “I’m not really an avid wooden boat owner, but Siwash is a member of the family.” The boat is berthed in Alamitos Bay and sails under the colors of Los Angeles Yacht Club. And, Siwash continues to be a regular visitor to the favored coves of Catalina.

Live from Beyond the Moluccas

Courtesy of NOAA Okeanos Explorer Program, INDEX-SATAL 2010

One of the gems among American museums is the Exploratorium—because it is all about exploring, not just showing. A whole generation has grown up with the Exploratorium’s interactive, engaged and engaging activities on-site in San Francisco, and on Wednesday, July 28, the Exploratorium is taking us on a live webcast tour of deep waters and strange creatures in Indonesia.

This is new science from a new platform on its maiden voyage. Think ocean exploration beamed live to students, the public, and fellow researchers all at once from a part of the world that NOAA chief scientist Steve Hammond calls, “an exciting place geologically and biologically.”

Since June, U.S. and Indonesian scientists have been working side-by-side on two ships, the Okeanos Explorer and the Indonesian research vessel Baruna Jaya IV. They are focused on the water column and benthic environments in unknown ocean areas in SATAL – a contraction of Sangihe and Talaud – two island chains stretching northeast of North Sulawesi. (My inner geographer was helped by thinking of the area as south of Mindanao.) A new multi-beam sonar unit has taken deep-ocean mapping to new levels of sophistication—only five percent of the ocean floor is mapped—and on the “fun meter” side, these folks are poking around the seafloor using the Little Hercules remotely-operated vehicle.

The NOAA Ship Okeanos Explorer was commissioned in 2008, with accommodations for 46 crew and technicians. However, the starting premise was that most of the science team would be working shoreside. On this maiden voyage, live images from the seafloor and other science data are flowing over satellite and high-speed Internet pathways to scientists standing watch in Jakarta, Indonesia and Seattle, Washington.

Sorta like the rest of us, but better equipped to understand what they see.

Courtesy of NOAA Okeanos Explorer Program, INDEX-SATAL 2010

I’ll be tuning into Wednesday’s Exploratorium webcast at 1500 PDT here, both live and archived. There will be additional live webcasts on August 3 and August 5, same time.

And I like this musing from Senior Survey Technician Colleen Peters, regarding the life of the oceanographer:

“In my opinion, Ocean Exploration is about 25% exhilaration and 75% perspiration. It is incredibly exciting to be on the cutting edges of technology, and getting to look at areas of the world’s oceans that have never been observed before. However, what most people may not realize is how many days at sea it really takes to get those few good images, that one great map and the dive that will change the course of history.

Courtesy of NOAA Okeanos Explorer Program, INDEX-SATAL 2010

“Being at sea is like living on a perpetual Tuesday. It’s not as bad as dragging yourself to the office Monday morning after the most amazing weekend away, nor is it like the anticipation of leaving work on a Friday afternoon with two whole days of freedom to relax and recharge still ahead of you. Tuesday is just after the start of the work week, but with many more days to get through to reach the next break.”

Wow. Perpetual Tuesday. See you on Wednesday, Colleen.

Visit the Exploratorium online here.

Cats 1, Cameras 0

Photo by Gilles Martin-Raget

The breeze got a bit feisty in the south of Spain recently and cost the America’s Cup defenders a day on the water of comparing camera angles, etcetera between monohulls and multihulls. The intent of the exercise is to have a practical test of which platform communicates more excitement to a television audience, but two-time Olympic gold medalist Roman Hagara of Austria put it this way, “For us, the waves were fun, but for the TV guys, it was a little wet.”

Ah yes, so much handier to have the shoreside vantage points of San Francisco Bay.

As of Sunday, however, four days of the “TV Trials” have been completed in the waters off Valencia, where the BMW Oracle Racing Team is still headquartered, pending a venue announcement for America’s Cup 34. You can view rough cuts here.

The word from the team:

VALENCIA, Spain (25 July 2010) – A strong sea breeze on the final day of the America’s Cup television trials concluded what has widely been regarded as a highly successful evaluation.

Over the past four days two high-performance monohulls and multihulls have been loaded with a plethora of cameras and microphones and put through match racing maneuvers to help find new camera angles and test surround sound format.

Racecourses were also modified by changing the percentages of upwind and downwind work to see if it helped keep the yachts engaged at close quarters.

“I’d have to rate the trials an unqualified success,” said BMW ORACLE Racing CEO Russell Coutts. “We plan to do this again in the coming weeks and months, but I think we found some things that work that we’d like to explore again down the road.”

One camera angle that got people’s attention was at the top of the mast looking down on the yacht. In HD format, the picture jumped off the screen with clarity and crispness. Those angles combined with the surround sound format helped create an immersive experience.

The trials were also used to test monohulls versus multihulls and the excitement they lend to television. A new yacht design is being created for the 34th America’s Cup, and concept papers have been issued to rule writers to create a monohull and multihull design.

Paolo dos Reis, on the Course, of Course

Even getting the course wrong in the “long distance” race was not enough to distract Brazilian champion Paolo dos Reis from his domination of the Windsurfing Nationals on San Francisco Bay. Paolo was able to skip Saturday’s final race, swallow the points, and still win the title with one point to spare of Maui sailmaker Phil McGain. A separate slalom event went to another Brazilian, Wilhelm Schurmann, with McGain second here as well—on a comeback regatta, after quite an absence. Full results here.

Plastiki’s Voyage Nearly Done

What began as a statement about the wasteful use of plastic is now a nearly-complete, 8,000-mile voyage across the Pacific. David de Rothschild’s 60-foot Plastiki left San Francisco Bay on March 20 and arrived last week on the coast of Queensland, Australia. That’s 400 miles north of the target, Sydney, but considering the gales that kicked up, late in the passage, and the fact that the world’s first recyclable boat was never designed to “point,” good enough is good enough.

Plastiki is scheduled for a Monday arrival in Sydney Harbour, its 12,500 recycled PET plastic bottles still in place and still in view, providing some 68 percent of the vessel’s buoyancy and making their own visual statement at the cost of otherwise-fair hullforms. The Kiwi company, High Modulus, consulted on the structure, which is made from fully-recyclable Seretex.

And let’s hand it to the team. They’ve succeeded in generating a lot of publicity and a lot of attention for their cause: “To see a significant reduction in the amount of manmade waste heading out to landfill and sea. We believe that with a small effort and some smart thinking everyone could reduce their use of single purpose plastic bottles, plastic bags and styrene foam. It’s achievable if we work together on making small changes in our lives.”

Arriving in Sydney, Plastiki and its crew of six will be met at the Heads and towed to the National Maritime Museum in Darling Harbour, where it will be on display for the coming month. More at theplastiki.com.


Brazilian champion Paolo dos Reis is still the man to beat (except that nobody’s beating him) at the US National Windsurfing Championship and Formula North Americans on San Francisco Bay.

Photo by Erik Simonson

As of Friday noon, the breeze was still building, but Stanford professor Francis Ludwig’s wind model was showing a working wind slot, sure enough . . .


What’s wrong with kids today?

Old (fast) Dogs

In the prognostications I saw, Phil McGain wasn’t even listed as a contender for this week’s Windsurfing National Championship. Why would he be? McGain blew off the racing circuit years ago in favor of a more recent obsession, running and competing in marathons and triathlons. Heck, the only board he owns is that six-year-old thingamajig that’s been hanging around the garage and—

No to overdo it, Phil McGain is president of Maui Sails, and it’s not as though he ever quit putting in time on the water. It’s not as though he ever quit thinking about sailing fast. But the 1989 world champion in course racing really did drop out of serious competition circa 2005. He came to San Francisco Bay for the Nationals with no particular expectations except to fly his sailmaking brand, and then found himself and that six-year-old board in second place after two days and seven races. “I think everybody’s surprised,” he said. “I’m a little bit surprised, myself. It’s been a while, but I feel as if I haven’t skipped a beat.

“I’m 47, and I’m racing guys in their twenties, but my fitness level is probably the best it’s been since my own twenties.”

The Formula boards that are being raced through Saturday along the San Francisco cityfront—right where I figure the America’s Cup match will be sailed circa 2014—have been through quite an evolution in McGain’s time. “If you go back twenty years,” he said, “the equipment was 12.5-foot boards with daggerboards and sliding mast tracks. I think our biggest sail was a 7.4 [7.4 square meters]. Go forward from that and there was a time when the boards were 27 inches wide. Now they’re 36 inches wide and our biggest sails are 12 meters. The idea is to have super-high performance in the light air that most of the world sails in. But I live on Maui, where we see a lot of 20 knots and 30 knots, and here we are beating ourselves up on San Francisco Bay.”

He wraps up with a grin as if to say, but of course.

Brazil’s Paolo dos Reis was the series leader after two days and clearly the man to beat for the overall title. McGain in second was a few points back with a lead of another few points over five-time Brazilian national champion Wilhelm Schurmann. Except that when you separate out the concurrent Grand Masters category, McGain—he’s Aussie by birth—is sailing in a category of one, with a double-digits lead on points.

Photo by Richard Ressman, Photosurgeon

There was that one race on day two when McGain got “a killer start” but then was afraid that he had killed himself by being over the line early. To be safe, he went back, re-started deep, and then climbed all the way through the fleet to finish first and ask himself, Did that just happen?

The races are being run by St. Francis Yacht Club, which has adopted an aggressive approach to re-defining windsurfing in the USA. A year ago the club bought itself a fleet of Techno 293s and set about building a junior windsurfing program. The Techno Worlds will be sailed in these waters a year from now, with the expectation of an international fleet in the hundreds of young windsurfers. The U.S. windsurfing rep at the Qingdao Olympiad, Ben Barger, conducted a youth clinic here last week. Here is what the man had to say: Ben Barger on youth development

As noted by USA 4, Steve Bodner, it’s been winter wetsuit weather on San Francisco Bay. The marine layer dropped a few hundred feet on Wednesday, to “only” 2,100 feet, and will probably clear further as the week goes along. With any luck there will be sunshine at Crissy Field for the wrapup racing on Saturday, and maybe a bit of freestyle competition as well. The racing also counts for men’s, women’s, and age-category titles of the Formula Windsurfing North American Championship. You can find the event website here.