Stu Johnstone
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Oct 13, 2009, 3:25 PM
Post #1 of 15
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I read with some degree of amusement the article in Scuttlebutt #2948 - WILL THE RIBLETS RETURN? In particular, because the ISAF RRS-53 has allegedly been dismissed for America's Cup #33? Riblets from 3M were one thing. "Hydrophilic coatings" are quite another-- e.g. the mythical "artificial dolphin skin". There's a lot more to the story on coatings and intrigue in the America's Cup than just the "riblets".
In 2002, I was working with friends at a major Midwestern university on the use of nano-particle technologies in batteries, capacitors, fuel cells and combinations thereof. One of the most remarkable "chance" meetings took place when after contacting George David via "Tomac" (Tom McLaughlin at North Sails), I was put in touch with United Technologies then Chief of R&D-- UTC was researching how to make better "inorganic" fuel cell membranes.
What came out of the discussion with our team and the UTC R&D guys was the fact that our nanoparticle coatings (consisting of 8-10 nanometer size particles made in my basement lab) were extremely "hydrophilic"-- e.g. the opposite of hydrophobic (like beads of water on wax). We then tested a hypothesis that our coatings might make water flow faster and perhaps also produce a thin coating on a boat that would act like the mythical "dolphin-skin"- the ultimate sailboat coating. Here's what happened and why it got mixed up in the America's Cup 2003 challenge in Auckland, New Zealand.
We tested our hypotheses by first doing the "contact angle" test - drop 1 cc of water on a surface with many different preparations and, using a microscope mounted horizontally (a specific piece of kit I might add), measure the angle that the wall from the bead of water forms against the surface). The finishes that were tested included; (a) sandpaper finishes from #36 to #400 to #800; (b) wax; (c) silicon spray; (d) teflon spray; (e) gelcoat; (f) various soaps, (g) various thicknesses of our SLIP nanoparticle SiO2 coatings, and so forth. In short, our hypotheses at a "simple level" tested out correctly--- other than soap which left virtually no contact angle, our nanoparticle coatings were so hydrophilic that most contact angles were well below 10 degrees. By way of example, #400 to #800 wet-or-dry gelcoat was next closest "standard" finish at over 30 degree contact angle.
Next, we decided to bite the bullet and do a real, honest-to-goodness test of our coatings with whom many consider to be one of the world's foremost experts in hydro-dynamics and computational fluid dynamics, particularly with respect to test tank data and coatings for racing sailboats and ships-- Prof. Ian Campbell at the University of Southampton/ Wolffson Unit in Southampton, England. We flew over and spent four days in Cowes, Isle of Wight, commuting across the Medina River early every morning to tow Ian's famous "plank" and also a Laser2 daggerboard through the tank. We tested both (i) resistance using Ian's famous "super-custom" Hewlett Packard digital gauges and (ii) visual flow using an underwater video camera and flowing ink.
In short, the results we produced were somewhat astonishing. For one, Prof. Campbell flat-out stated that in 40+ years of testing every conceivable crazy idea regards bottom coatings that NOTHING (other than the obvious soap) had ever tested as fast as our "SLIP Technologies" nanoparticle coatings (SLIP = Super-Laminar Industrial Products). What we discovered after testing both the "plank" and the Laser2 daggerboard was that once laminar flow was established (1 knot to about 12 knots), the SLIP coating was up to 8.0% faster than #600-#800 wet-or-dry sanded gelcoat/polyurethanes-- e.g. several boatlengths on a 2 mile beat. And, more remarkably, the laminar flow separation on the Laser2 board was dramatically improved- moving the point of separation up to 30% further back on the chord length. What does that mean? Well, the boat moves faster through the water for one and, secondly, the foils provide significantly greater lift than with conventional finishes since the hydrophilic coating was behaving like an artificial "dolphin-skin"- holding a super thin-film of water molecules against other water molecules to promote laminar flow.
With those two well-documented discoveries, we then decided it was time to figure out how well it worked in the real world. And, here's where the intrigue goes off the charts. I will simply explain three scenarios and the rest of the world can debate what ultimately happened:
1. 2003 America's Cup- Auckland, New Zealand- In the fall of 2002, I first contacted Ken Read, Billy Trenkle and their Reichel-Pugh Design office regards the STARS & STRIPES efforts since they were friends (I'd sailed with them all, plus my buddy Kenny Read from Newport was skippering). Initially disbelieving our findings, the S&S guys did get an "opinion" from the Chief AC Measurer (a Kiwi) that specifically allowed any kind of "commercial coating" (SLIP's coatings were offered online in my Yahoo Store). With one last key race to go, the call came in from Stars&Stripes to "ship it now"...but the guys seemed to forget I had to make it in batches (which took 3 days) and ship it cool (so the nanoparticles wouldn't coagulate and recombine into clumps before getting sprayed on the hulls and appendages). Failing to help out STARS & STRIPES, I then called Bruce Farr's office regards Larry Ellison's BMW/ORACLE campaign (I'd worked with them - mostly Staggie (Geoff Stagg), Russell and Renee- on various projects, including one with the late Sir Peter Blake on a VOR60 project). As I'd done for Kenny and DC, I offered to help; exchanged notes (plus our research). But, the response I got from BOR was "while we believe Prof. Campbell's data (and have worked with him extensively), our test tank and 20 foot scale model that we have in Auckland exclusively is too full and we don't have the time to do this right now". Oh well, both lost....BADLY. It certainly wasn't from our lack of trying to help fellow Americans, that's for sure.
2. Etchells 22 Worlds- in early summer 2003, I got a call from Kenny Read/ Karl Anderson one day asking if I still had that "stuff" that's "slippery when wet". All kidding aside, I said "yes" and shipped him about a gallon to test on Long Island Sound prior to the Etchells Worlds. The test was done with Kenny's two identical Etchells, one coated, one simply sanded. On board for the test was Ched Proctor from North Sails CT and Karl Anderson of the famous Karl's Boatshop on Cape Cod. After the test, I spoke to Karl and his statements were simply astonishing-- to paraphrase his comments, Karl said "...it didn't matter WHERE we put the coated boat, it simply sailed away. Upwind, downwind, reaching, windward, leeward, ahead, behind...it was unbelievable." Well, proof is in the pudding and the jury is still out on this one-- Kenny won that Etchells Worlds with STRAIGHT FIRSTS--- it's never been done before or after. And, his formula was simple- start to weather of the mid-line boat and sail away-- Stew Neff can corroborate the difference in Kenny's straight-line speed and performance (as can many others) who'd raced against Kenny and crew that year.
3. British Sailing Team- 2004 Olympic Games- Athens, Greece- of all people who were "in the know" of our SLIP nanoparticle coating, it was our British friends on the Medina River in Cowes, IOW, England. The British were leaving no stone unturned to dominate the Athens Sailing Games-- they certainly pulled it off. After an email from one of the RYA Sailing Team leaders, I shipped over 8 liters of our SLIP coating to their team hotel in Athends, enough to cover every boat/ tuneup boat the British had from boards, to 470s, to Ynglings and so forth- twice. The rest is history.
Best,
Stu Johnstone
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