Monohull Speed: Speed Dream by Vlad Murnikov

Discussion in 'Sailboats' started by Doug Lord, Jan 8, 2010.

  1. Gary Baigent
    Joined: Jul 2005
    Posts: 2,959
    Likes: 102, Points: 63, Legacy Rep: 509
    Location: auckland nz

    Gary Baigent Senior Member

    Well yes, but also the straight foils too. I was really thinking of halting leeway. The curves in foils have to be a compromise, lift and anti leeway, angled out just anti-derive, as they say. The point of M1's near horizontal lifting foil to leeward (I've actually posted about this before) the double ended foil went through the hull and I think they had problems with this in tacking, the weight and complexity of the mechanism - but I;m only guessing. I saw it beating once and it looked okay, but there was no other boat beside M1 to give an indication of the foil efficiency, I mean, pointing up and going fast. I was on my foil tri Groucho going the opposite way and M1 passed close by. Simon Hull, if you're reading this, give us the gen. Your hydrodynamicist father designed the system I heard.
     
  2. ancient kayaker
    Joined: Aug 2006
    Posts: 3,497
    Likes: 146, Points: 0, Legacy Rep: 2291
    Location: Alliston, Ontario, Canada

    ancient kayaker aka Terry Haines

    Why mono vs multi anyway?
    What is more important - speed or hull count?

    An obvious question hovers over the SpeedDream concept. If movable ballast can aid a mono, then can’t it do precisely the same thing for a multi? Surely it is simpler and safer to pick up and dump water ballast at speed in a wide intrinsically stable multi than shift a lead weight from side to side on a skinny mono. Juggling demands quick reflexes.

    While I acknowledge and respect Vlad Murnikov’s courage and ability to raise funding for his experiment, I have to wonder what the SpeedDream will achieve. If it works and is faster than a comparable multi, the multi can easily do the same thing, and without incurring the initial weight penalty.

    SpeedDream is obviously not intended to be a mere sprinter; she would lose to the first sail- or kite-boarder to challenge her, and she cannot compete in the same category or conditions as Sail Rocket for example. So ocean racing is her venue. What happens to her if she encounters a sudden reversal of wind direction with ballast fully extended, or the crew get their instructions or timing wrong during a tack? These things happen during a long race especially as crews tire, and the boat must survive them in racing condition - not merely intact or still floating.

    So what advantages will SpeedDream retain over a multi? she may be a bit more agile, but only with her ballast keel centered and I wonder how much of an advantage that is for ocean racing anyway. She can vary her heel angle - artificially if necessary in light airs - to optimize her underwater hull shape. A racing tri can do that, amas can be optimized for planing while the center hull is optimized as a displacement hull for light airs.

    That seems to leave only the ability to recover from a capsize, provided she is not too damaged by a highspeed flipover and can move the ballast keel back to center while on her ear - big questions those. That would allow her to sail closer to the edge, but only to the extent that she would compete well against other monos.

    So why the multi vs mono issue in the first place?
     
  3. Doug Lord
    Joined: May 2009
    Posts: 16,584
    Likes: 299, Points: 93, Legacy Rep: 1362
    Location: Cocoa, Florida

    Doug Lord Flight Ready

    Speed Dream

    Here is a post by Vlad on SA speaking to the comments in blue:

    Posted Today, 08:56 PM

    I appreciate time and effort you've put writing such a comprehensive commentary. It has to be said though that most of your questions were answered in the original post by Brian Hancock, and if you'd like, you could find them there. http://www.sailinganarchy.com/index_page1.php
    Still, here are several remarks.


    To be clear, I'm a monohull fan. But I don't see how adding lead gets you to more speed than adding a second hull. I just don't see how you can accomplish equivilent RM at the same displacment. Less weight, in a well designed boat, implies less drag. With equal righting moment and equal horsepower, the boat with less drag goes faster. How are you going to go faster when you have more drag, more weight and the equivilent horsepower?
    Multihull sails fastest while flying a hull. Then it's no different from the SpeedDream, with just one hull in the water and the other one - or two - plus all the connecting beams nothing more than ballast. And which ballast is more efficient - a simple streamlined bulb or all these contraptions hanging out in the air? All that extra windage...
    Theorethically, it's not that difficult to match mutihull's RM with mono's telescoping keel, but there's no need for that. SpeedDream's planing hull would have only half wetted surface of the similarly sized multi, so even with less RM and sail area she would sail faster. As others have posted earlier, multihull too could have planing hulls, but that's not that easily achievable...



    While you can draw some nice pictures of your keel bulb and fin above the surface of the water, life at sea isn't quite as static as the pictures might suggest. Each time that bulb and fin touch the water, your drag numbers sky rocket. Sure, a multihull has that same issue, but when their airborne hull touches down, it begins to float and stops the rolling. When your bulb touches down, it happily contines to accelerate downards a long, long way and during that time, your boat speed is dropping like a lead balloon (no pun intended). The time required to again fly the multi's hull is much, much less than the time it takes to get your lead out (pun intended). What's your VPP estimate of the effects on average speed between your design and a multi-hull design when each experiences "touchdown"?Both multihull and SpeedDream would deep their respective floats/bulb when heeling moment gets lower than RM . The equilibrium is restored when either action of a helmsman or a trimmer, or another puff would pull floats/bulb out of water again. There's no difference between the SpeedDream and the multi in this regard. But now think which one creates more drag when it temporarilly come into water: A tiny bulb or a ten-times larger multihull float?


    Finally, regarding stability.
    Capsize in the open ocean is most often caused by extreme breaking seas, which violently roll the boat. In such cases, no amount of RM will prevent capsize. Its true that monohulls can come back up, but there's nothing about your design that will prevent roll over in such conditions. With all due respect, your design, like any design, is about a capsize-proof as the Titanic was unsinkable.

    With all due respect, have you been to the ocean on a fast boat? Capsizing by breaking seas is mostly for slow boats. When sailing fast, close to wave speed or faster, you have much more control, and there's usually enough time to react. Sure, things could get out of hands and any boat could capsize, theoretically. But how often do you hear about VOR70 capsizing? (let's keep our fingers crossed)... And don't forget, SpeedDream would much more stable.

    But much worse than most designs, the RM advantage of a canting keel design comes only as the result of complex electro-hydraulic-mechancial systems. A system failure - even a blown fuse - has a devastating effect on your stability. A chinese gybe changes the sign of your RM in an instant!
    What are the chances for a chinese gybe for a boat that would sail most of the time at 30 degrees AWA or closer?
    As for reliability, hydraulics are among the simplest, most reliable and wide-spread systems developed by man. But you are right, of course, anything could break. Carbon fiber beam of a trimaran could break...


    click on image then again on resulting image:
     

    Attached Files:

  4. Doug Lord
    Joined: May 2009
    Posts: 16,584
    Likes: 299, Points: 93, Legacy Rep: 1362
    Location: Cocoa, Florida

    Doug Lord Flight Ready

    Speed

    ===============
    Terry, when I was a kid I was convinced that the fastest sailboats around were multihulls and always would be. Well, the little Moth with its two foils changed that forever: the fastest sailboat under 20(25?)' is now an 11' monohull-it is faster than every monohull and every multihull! I wouldn't have believed such a thing could happen until about 10 years ago-it is really quite remarkable.
    And I am completely convinced that a large mono can be designed using the latest technology -and what the Moth has taught us- to be faster than the same length multihull.
    I hope Vlad can do it-but regardless, it will be done!
     
  5. cardsinplay
    Joined: Oct 2010
    Posts: 330
    Likes: 3, Points: 0, Legacy Rep: -74
    Location: Camp Plasma

    cardsinplay da Vinci Group

    When one can't make a monohull faster than the typical multihull, the answer always seems to be... "hey, let's pile all sorts of gadgets on the boat that require an insanely more complex operating regime, risk our asses because it takes split second timing to pull it off in the most outrageous weather and sea state variability imaginable in the Southern Ocean and on a scale that has FAILURE written large all over it."

    Failure due to stratospheric operating costs. (see Speedboat for a tiny idea as to how successful this boat will be if it ever gets its butt off the hard) Failure due to the intensely small number of sailors who might even be close to the skill and timing level necessary to make it all go properly and Failure... because the loads and limitations of conventional composite build techniques will expose the fragility of the entire system time and time again.

    Here's my bet... the small boat version will prove to be more than a handful and only in the most abstract of conditions will it produce anything even close to its designed performance levels. Sponsors for the monster version will run for the hills and take their money with them. The designated skipper will see that his already semi-parked big ocean sailing career is now over and will go back to farming and self-sufficient lifestyle development. The design team will fall away into the shadows with only the smallest of anguished explanations and SpeedDream, just like Speedboat, will soon fade from memory making it clear, once and for all, that monohulls are not supposed to go after records held by multihulls any more than a Bantam Weight fighter should be in the ring with a brick-handed Heavy Weight.

    Of course, the folks involved can prove me wrong and if so, I'll be happy to say I'm sorry right here on these pages. To do that, their effort will have to wrest away all the major oceanic crossing records now held by multihulls, as well as the Jules Verne Trophy for a RTW sailing record for crewed vessels. Anything less is a failure... and they know it.

    Oh, baby, won't Dougie be in one major tizzy of confusion if this huge boat ever gets built? After that display of frothing spittle over the Route du Rhum and Groupama 3's capture of line honors, Doug will have to disavow his heated allegiance to G3 and Franck Cammas and direct it to his latest love affair of the week in the form of SpeedDream. Like a Hollywood starlet, torn between two virile lovers, I'm sure he'll have a catastrophic meltdown of global proportions. It couldn't have been scripted by Kim Kardashian, or Paris Hilton, any better.

    Stay tuned as Doug, foil technology, swinging keels and the allure of a heady Russian romance in pursuit of elusive world records, achieve their own version of the China Syndrome and melt their way right on through the earth in a completely haphazard fashion.
     
  6. cardsinplay
    Joined: Oct 2010
    Posts: 330
    Likes: 3, Points: 0, Legacy Rep: -74
    Location: Camp Plasma

    cardsinplay da Vinci Group

    Unfortunately for these rather dodgy dreams, there are already several men who have eclipsed any mark so described with their boards and kites, that any Moth rider in his wildest imagination will ever set. All hail the fastest sailing boat on the face of the earth AT ANY SIZE.... a Rob Douglas piloted kite board

    Long live the slow poke Moth. The Moth is dead.

    Don't believe a kite board is a boat... go take a long look at the Mirabaud foiler in Switzerland.
     
  7. ancient kayaker
    Joined: Aug 2006
    Posts: 3,497
    Likes: 146, Points: 0, Legacy Rep: 2291
    Location: Alliston, Ontario, Canada

    ancient kayaker aka Terry Haines

    Sticking to the point, which is ocean racing - Card’s* post above had a point buried in it; while I do not oppose complexity, I view it with suspicion until it proves its worth.

    Vlad’s comments add to my understanding where he compares a multi flying a hull to the SpeedDream “flying” the ballast keel. In this condition the windage of the multi’s raised hull is a disadvantage. While the raised hull functions as ballast, it performs other valuable functions as well, whereas the ballast keel is just weight. This technology is most valuable into the wind, but the closer this boat sails to the wind the greater the risk. Recovery when wind shifts and heeling abruptly ceases is automatic in a multi-hull but when it increases suddenly, recovery in the SpeedDream is utterly dependant on an alert skipper and a well-trained crew; all hands on deck for the upwind run and no rest for the wicked, sorry guys. It’s not going to be a reflex like riding a bicycle. Personally I prefer buoyancy over weight any day, at sea.

    Nonetheless, I truly hope that it works as expected and opens up another avenue for designers to explore. Nobody wants yacht design to become static - except perhaps the current record holders!

    * but really, Cards, "monohulls are not supposed to go after records held by multihulls" ... what were you thinking?
     
  8. RHough
    Joined: Nov 2005
    Posts: 1,792
    Likes: 61, Points: 0, Legacy Rep: 793
    Location: BC Summers / Nayarit Winters

    RHough Retro Dude

    Doug,
    This all hinges on a definition of "sailboat".

    Simple physics and geometry says that once a sailing craft is planing, or supported by foils length has no bearing on speed.

    IMO a Moth on foils is no more a boat than a sailboard or kiteboard, both of these sailing craft will leave a Moth for dead. Moths are stuck in the mid thirties for speed, TWENTY KNOTS slower than fast sailing craft.

    There are facts you continue to ignore.
    One, truly fast water craft do not use hydrofoils.
    Two, Moth dynamics do not scale up.

    It has been almost 10 years since foils changed the Moth class. If single track foils are the universal solution to everything, where are all the double handed and larger foilers? Wasn't there an attempt to convert an 18 foot skiff to the Moth configuration? It's been a few years, how is that working out?

    Bethwaite made some great observations about reverse scale effect. It all has to do with the relatively fixed size of autonomous Smart Ballast(tm). Smart Ballast(tm) systems were designed as stand alone systems, when the size of the vehicle that relies on a Smart Ballast(tm) system exceeds the capacity of a single system, two systems networked do not have equal response time. As the vehicle gets scaled up the Smart Ballast(tm) systems become a smaller percentage of the total vehicle weight. This combined with the chinese fire drill aspect of networked Smart Ballast(tm) systems make the likelihood of a successful large Moth a very remote possibility.

    Every year that passes without the emergence of large scale moth system "boats" should tell you that such a breakthrough becomes less likely as time passes.

    Do I need to dig up the posts where you make a very convincing argument that more than two foils has to be slower since such a system has 33% more drag? Now you look at this canting Rube Goldberg nightmare with no less than 5 apendages and think it will be faster than a multi?

    Did you even read what you posted?:
    No Difference? Lead floats?

    Clueless.

    R
     
  9. Paul Scott
    Joined: Sep 2004
    Posts: 303
    Likes: 8, Points: 0, Legacy Rep: 84
    Location: Spokane, Wa

    Paul Scott Senior Member

    But with that much control over the swing keel, if the thing capsizes, you could conceivably just roll it back over and move on. It would have to be designed with that in mind, like no one on deck in the bad stuff, and a rig, deck, foils and hull that would welcome the abuse, but, for example Lasers and Windsurfers do that now. Of course, bigger means more of a challenge design wise, but with the ability to push that hard, you could rapidly devise handling techniques. With a Mono, you can push harder, with a Multi, you've got to back off. But it would be, er, interesting to hit something in the ocean, like a container, though.....

    Perhaps joystick control over the keel? That would be a ride!
     
  10. RHough
    Joined: Nov 2005
    Posts: 1,792
    Likes: 61, Points: 0, Legacy Rep: 793
    Location: BC Summers / Nayarit Winters

    RHough Retro Dude

    Not to be argumentative, but ... :)

    If you sailed a 50-90 ft multi at 50-90 ft mono speeds, you would be in no danger of capsize. The only reason to push a multi to the brink of capsize is to beat other multi's.

    Monohull, up to 60 foot.
    2000 "Union Bancaire Privee" 60ft, Dominique Wavre, FRA, 430.7nm. 17.94kts
    2001 "Armor Lux" 60ft, Bernard Stamm, SUI, 467.7nm, 19.48kts
    2003 "AT Racing" 60ft, Alex Thompson, GBR, 468.72nm. 19.53kts
    2007 "Hugo Boss" 60ft Alex Thompson/Andrew Cape, GBR, 501.3nm, 20.9kts

    Up to 60 foot.
    1994 "Primagaz" 60ft Tri, Laurent Bourgnon, FRA, 540nm. 22.5kts
    2006 "Mediatis-Region Aquitane" 60ft Cat, Yves Parlier FRA and 5 crew 597.81nm. 24.91 kts
    2006 "Brossard" 60 ft Tri, Yvan Bourgnon SUI, 610.45 nm. 25.76 kts
    2007 "Banque Populaire" 60ft Tri, Pascal Bidegorry, FRA, 667nm, 27.8kts

    So a 13 year old Tri is still faster than a 2007 60ft mono ...

    The 2007 numbers of 501 to 667 would indicate to be as fast as a mono, you can sail your multi at about 75% ... hardly pushing at all.

    But if you really love your lead you can motorsail:
    2005 "Movistar" 70ft, Bouwe Becking, NED, 530.19nm, 22.09kts
    2005 "ABN AMRO ONE" 70ft, Mike Sanderson, NZL 546.14nm, 22.75kts
    2006 "ABN AMRO TWO" 70ft, Sebastien Josse, FRA, 562.96 nm, 23.45kts
    2008 "Ericsson 4" 70ft, Torben Grael BRA, 596.6nm, 24.85kts

    Then you would be as fast as the 60ft multi sailing at 90%

    Very much off topic but it speaks to the challenge. Say you want to average 10 knots without killing yourself with effort (Canada to Mexico in 2 weeks). A 45*30 cruising multi can do that at 76% of top speed of about 13knts (reaching in 15kt). This requires a 95 ft mono (S/L ratio 1.34 = 13).

    What do you call it when you keep doing the same thing and expect a different result?

    Prior to the W60's in 1994 the average *record* 24 runs for monos averaged S/L 1.32 The W70's are in the 2.8 S/L range.

    Multi's averaged S/L over 2.0 while the mono's were stuck at 1.32, in the modern period where the cream of the motorsailers has hit S/L 2.8, the multi's are at 3.3+

    Just why would anyone think this boat will turn the record upside down? Why all the effort? Because the thing is skinny and easy to park in a marina? Oh wait, it can't get into most marinas because it draws too much water.

    R
     
  11. Doug Lord
    Joined: May 2009
    Posts: 16,584
    Likes: 299, Points: 93, Legacy Rep: 1362
    Location: Cocoa, Florida

    Doug Lord Flight Ready

    Speed

    ====================
    Did you miss this thread? http://www.boatdesign.net/forums/sailboats/mirabaud-lx-2010-a-33020.html

    And who said that "single track"(whatever that is) foils are the solution to everything? I think foils-bi-foiler and/or other combinations may well be a good solution for speed and/or speed and comfort inshore and offshore.
    Oh, and by the way the fastest sailboat on the planet is still Hydroptere which holds the CURRENT record over the nautical mile.
     
  12. Doug Lord
    Joined: May 2009
    Posts: 16,584
    Likes: 299, Points: 93, Legacy Rep: 1362
    Location: Cocoa, Florida

    Doug Lord Flight Ready

    Speed

    1) The Moth is held back, to an extent, by its own class rules-a souped up Moth or bi-foiler is likely to be capable of much more speed. Smaller foils, manual altitude control, variable geometry foils, "Power Foils"(small foils used exclusively for RM in stronger winds) all could add speed. But it is the fastest "sit-in/on" sailboat under 20'! You ain't seen nothin yet....

    2) Reverse scale effect? Give me a break. Julian Bethwaite along with Paul Cayard and Russell Coutts came up with the Pterodactyl concept years ago-it would have used either on-deck sliding water ballast or on-deck sliding lead ballast(Coutts). I talked to Julian about this and he was 100% convinced it could be done either way. The technology was available back then and is sure to be available now and even better in the future.

    http://www.boatdesign.net/forums/sa...ng-monofoiler-design-discussion-15143-12.html, post 171

    also see this thread,post 74 "flying canting keel"
     

    Attached Files:

  13. cardsinplay
    Joined: Oct 2010
    Posts: 330
    Likes: 3, Points: 0, Legacy Rep: -74
    Location: Camp Plasma

    cardsinplay da Vinci Group

    Geez, Randy, it looks like you're going to have to haul out the lance and joust with imagery that long ago hit the bin in Bethwaite's shop. Funny how this stuff keeps popping-up to justify flakey arguments. Perhaps the most interesting aspect, though, of those old timey images, is that none of them show a boat sporting lifting foils for flying.... Certainly not the ones you see above. Though that will probably change in the fashion that our boy regularly seeks to alter history with the edit feature on these pages.

    No, what you see there is a boat that is basically an Open 60 with an anorexic main hull and then equipped with.... Oh, no!, they're not really suggesting.... amas, beams and all that multihull stuff, are they? Good God, that's pure blasphemy for any self-respecting monohuller.

    The last bit, which is probably the most poignant of them all, is that the thing never got built, never advanced to anything more than the, "hey, what say we try this?", stage and some beer driven conversations that weren't really serious in the first place. You know they weren't serious, because not one of those dudes, who always seemed get mentioned as some form of gravitas on the project, ever stuck any of their own money into pushing it along.

    DOA then, now and ultimately pointless as an example.
     
  14. Doug Lord
    Joined: May 2009
    Posts: 16,584
    Likes: 299, Points: 93, Legacy Rep: 1362
    Location: Cocoa, Florida

    Doug Lord Flight Ready

    ==========
    That absurd comment is where you fall off the deepend....
     

  15. ancient kayaker
    Joined: Aug 2006
    Posts: 3,497
    Likes: 146, Points: 0, Legacy Rep: 2291
    Location: Alliston, Ontario, Canada

    ancient kayaker aka Terry Haines

    The mention of the moth was an irrelevancy in this thread. Unfortunately it has triggered more discussion that it deserved. the moth has nothing to do with SpeedDream. Planing vs foiling, large vs small, LeadFoot vs crew balance, complex vs simple, large crew vs single-handed, the list goes on. I shall not. Let's get back on topic.
     
Loading...
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.