The next (2016 or so?) America's Cup (AC 35)

Discussion in 'Sailboats' started by Stephen Ditmore, Oct 9, 2012.

  1. Stephen Ditmore
    Joined: Jun 2001
    Posts: 1,388
    Likes: 44, Points: 58, Legacy Rep: 699
    Location: Smithtown, New York, USA

    Stephen Ditmore Senior Member

    In the current atmosphere of a new class (of catamarans) and rapid technical development, the 2013 Louis Vuitton Cup and America's Cup will be a testing ground and learning opportunity for everyone involved (not just the finalists). How will it affect the longer term future of the America's Cup? How will it affect production and custom sailboats and the sport of sailing beyond the America's Cup? Should designers and sailors be bound by contractual obligations to their teams once America's Cup 34 is over? Who should make the rules going forward, and what should they be?

    The intent of this thread is to separate discussion of the America's Cup beyond 2013 from discussion of America's Cup 34, which is taking place at http://www.boatdesign.net/forums/multihulls/34th-americas-cup-multihulls-34612-46.html#post586412

    Discussion of the Little America's Cup (a.k.a. the International Catamaran Challenge Trophy and now the International C-Class Catamaran Challenge) and what it's relationship should be to the America's Cup, is also invited, as is discussion of the Canada's Cup and other match racing events.

    An aside: someone needs to update the pages that come up when I google "Little America's Cup", starting with Wikipedia, to better explain how it morphed into the ICCC and what has become of the ICCT.
     
  2. SteveMellet
    Joined: Sep 2009
    Posts: 196
    Likes: 7, Points: 0, Legacy Rep: 88
    Location: South Africa

    SteveMellet Senior Member

    Too many questions in one post, but here's my take on it :
    "Who should make the rules going forward,"
    The winner of the 34th together with the accepted challenger, as per the AC Deed.
    "and what should they be?"
    Whatever the two parties involved decide.
    They should, in my opinion, outlaw afterburners for safety reasons, for the competitors overlapped astern and to leeward.

    The LAC / ICCC / ICCT is in more of a mess than the AC from a public understanding point of view. The LAC had that name for generations until some mad hatters who "owned" the name America's Cup prevented them from using AC in their title, despite having done so for a few decades. How ironic that the real AC is now a scaled up version of the LAC. They then changed names, then changed boats, then changed names again, then changed boats back to what they were. One day we can call them the LAC again without fear or copyright infringement. This was a bad period for multihull enthusiasts..

    Designers and sailors should be bound by whatever contractual obligations they signed their name to.

    I don't see trickle-down to club racing with foiling wing-sailed catamarans, but lots of multihull sailors and designers are looking very differently at foil design, headsail design, and other ideas which are coming out of this round of design ideas. Ben Hall built an A-class wing for the same budget as a mast and sail, with some refinement this could become mainstream. Nacra have curved lifting foils in more than one of their off-the-shelf production boats. T-foil rudders are as old as the hills in the F16 class.

    The real issue is, now that these world class sailors have been flying at over 40knots, will any of them be able to sail at 6knots again ? And would anybody watch another round of paint drying in monohulls ?
     
  3. Doug Lord
    Joined: May 2009
    Posts: 16,624
    Likes: 305, Points: 93, Legacy Rep: 1362
    Location: Cocoa, Florida

    Doug Lord Flight Ready

    AC Next

    Stephen, there is a thread under "Multihulls" for the Little Americas Cup in the UK in 2013: http://www.boatdesign.net/forums/multihulls/little-americas-cup-uk-2013-a-37972.html Also there is this, possibly dated, thread: http://www.boatdesign.net/forums/sailboats/americas-cup-whats-next-31489.html
    --------
    There was a time I'd get a lot of flak for bringing up foils in a thread like this.
    My how things have changed!
    Based on how well the Moth performs and the fact that it and boats like it can generate up to about 40% of total RM from Veal Heel* I'd bet that sooner or later a large monofoiler will sprint on to the scene and blow all the cats away. I mean the 11' Moth is the fastest sailboat under 20' beating all cats and all monohulls! By using Veal Heel to get a whole bunch of RM "for free" the monofoiler will have a good chance at bringing monohulls back to the Cup with a net increase in speed, I'd bet.
    You never can tell about the vagaries of billionaires but I think they'll have a hard time going back to leadbellies after the extraordinary examples of sailing design we are seeing now.

    * For those that don't understand Veal Heel, it is a technique developed by Rohan Veal that does a number of things:
    1) the boat is heeled to weather moving the CG of the boat + crew substantially to windward of the center of lift of the hydrofoils. This can result in an increase in RM without any movement of the crew: Take the example of the boat sailing upwind with the crew hiked out max. The crew can heel the boat to weather without moving and just doing that increases RM up to 40%.
    2) The vertical fin is unloaded as the hydrofoil develops a good deal of lateral resistance which can help prevent the vertical fin from ventilating.
    3) There is a vertical component to the rig that helps to unload the foils.
    4) the crew is lower and the aerodynamic drag of the boat+crew goes down as a result.
     

    Attached Files:

  4. Stephen Ditmore
    Joined: Jun 2001
    Posts: 1,388
    Likes: 44, Points: 58, Legacy Rep: 699
    Location: Smithtown, New York, USA

    Stephen Ditmore Senior Member

    If I were to answer my own question about what the rule should be, I'd prefer something extremely open. Say anything goes that will fit within a sphere of a certain diameter (so no dimension may exceed that diameter), and relies on wind, human, and/or solar power. I think there should be a minimum weight and a scantling rule or some general engineering standard that must be followed. I'd limit crew by total crew weight to give the ladies (and skinny people in general) an even shot. Computers on board would be legal, but fly-by-wire would not, and there should be a limit on battery discharge between beginning and end of the race.

    Is that too pie-in-the-sky an ideal?

    Then there's my totally retro side that would like to see some modern variant of the square meter rule (see the links page of my website, last paragraph) that would produce lighter weight versions of IACC boats not unlike a giant version of the 10 rater RC class. Still, I would want it to be more open than the IACC class became. That rule clearly underpenalizes length and overpenalizes light displacement. Would it be so hard to use a tweaked (from past IACC experience and data) VPP to recalibrate the base formula and get it right (instead of making it further restrictive with add-on corrections and limits, which is what they did)? Hopefully the result would look like a modern version of this (or similar to giant Etchells, Dragons, or KOD 33s).

    That same retro-self wants to see nationality rules restored for both crews and designers.
     
  5. Stephen Ditmore
    Joined: Jun 2001
    Posts: 1,388
    Likes: 44, Points: 58, Legacy Rep: 699
    Location: Smithtown, New York, USA

    Stephen Ditmore Senior Member

    Doug, you're enthusiasm's great. I'm skeptical that even a moth style hydrofoil will be quite as fast as a good hydrofoiling multi, and I'm about to say why, but whatever arguments you and I might marshal the way to answer the question is to race under an open rule that allows boats of different types to compete on a fair footing.

    I see stability/displacement as the basic equation of speed. That's basically power/drag. Mathematically it might look like Righting Arm / Displ^(1/4) [or would it be Righting Arm / Displ^(1/6)? I'm not trying to make it dimensionless; I'm trying to make it relate to velocity]. There are many components of drag and ways to reduce it, but there's no denying you need the horsepower. Whatever attitude you can imagine a moth in, you can imagine it as the leeward hull of a catamaran in the same attitude with a big lever to windward, the crew at the end of that lever, and a hull there just in case the lever should dip. The multihull will have more power. A mono-foiler may be better in some conditions, but when the wind picks up the multihull will have a decided edge.

    A topic that's come up in the AC34 thread is whether windward foil(s) that create downward force should be allowed. They could, in tandem with leeward foil(s), create righting moment far beyond what would be possible using the weight of the boat alone. I think there should be some required engineering standards written into the measurement rule, and engineers need to know what the design load is.

    From http://www.boatdesign.net/forums/multihulls/34th-americas-cup-multihulls-34612-46.html#post586462
    I contend a foil of limited area can only generate so much force. The leeward foil will have more force on it than the windward, so if they are similar in area and the windward foil remains submerged I'd expect the leeward foil to stall or cavitate first, lowering that hull to the water. And there are other ways a team could design a failsafe. Instead of limiting righting moment, the rig could be engineered to limit heeling moment. A release similar to a ski binding could be designed into the sheeting system, or sheets could simply be sized to break before other things. Or it could be made explicit in the rule that electro-mechanical devices monitoring shroud tension, linked to devices that can dump sail pressure, are required. I think that would be enough. Boats that break don't win, so I don't see the incentive for a team to deploy things that break the boat.

    There's a scenario that doesn't fit any of the analysis above neatly: a kite sail flown from the leeward hull. But can one match race using kite sails ...?
     
  6. petereng
    Joined: Jan 2008
    Posts: 581
    Likes: 21, Points: 28, Legacy Rep: 252
    Location: Gold Coast Australia

    petereng Senior Member

    Hi All - I've been asked to contribute here about the AC35th but I don't see much point discussing it. The AC is a challenge cup. The AC itself is a "deed" which cannot be changed. Until AC34 is decided and a new challenger stands up and is accepted then who knows what happens in the next few years? They can race in any type of "sailing" boat from 44ft to 110ft. History now tells us that boats over (a round figure) 75ft say are too big for manual control. The AC33 proved that the boats had to use motors and at this point of time this has been decided that push button sailing is not "sailing". If we allow electronic control of foils, motor control of "sail" it becomes a technology war more then now. This is all fine of the Defender agrees to it. The AC has always been about the fastest boat not neccesarily the fastest sailor (now called athletes to improve our profile & marketability). In terms of the foiling debate everyone seems to think that these are breakthroughs but they are relatively simple mechanisms that are stunted by the current rules. I'm an engineer that is asked to design mechanisms, structures and all sorts of things in the industrial environment. Given the money and resolve we could design very good foilers for any size boat. Hydroptere is the leading boat of its type and its been a long journey. But foilers are limited by the problem of cavitation and perhaps SWATHS maybe the way to go. A SWATH with foils to increase the boats Rm would operate in a far more stable condition then a foiler. But this is all here say. We have to wait until the AC35 to find out what happens. We may enter an era of conservativism and go back to 60ft monos like the Volvo!! Peter
     
  7. Ad Hoc
    Joined: Oct 2008
    Posts: 6,199
    Likes: 415, Points: 83, Legacy Rep: 2488
    Location: Japan

    Ad Hoc Naval Architect

    SWATHs have too much WSA for this application.

    Forgot to add. SWATHs 'work' by having a low righting lever, thus require a large displacement to have any appreciable righting moment.

    Not ideally suited at all.
     
  8. petereng
    Joined: Jan 2008
    Posts: 581
    Likes: 21, Points: 28, Legacy Rep: 252
    Location: Gold Coast Australia

    petereng Senior Member

    Hello Ad Hoc - military swaths are some of the fastest "surface" craft around in very poor sea states. By using foils to increase righting moment the sailing craft can have as much drive as they want. You either get above the waves or below the waves to go faster. Above the waves has stability problems below the waves hasn't been tried yet. If we are just up against the WSA then we just need a bigger "engine" or sail area. A swath can be any displacement. Peter S
     
  9. Ad Hoc
    Joined: Oct 2008
    Posts: 6,199
    Likes: 415, Points: 83, Legacy Rep: 2488
    Location: Japan

    Ad Hoc Naval Architect

    You're going to have to qualify that. The fastest swath in the world currently is at 31knots...and by the way it is commercial not military!

    I don't think you fully understand how a SWATH works.

    SWATHs decouple their motion from the waves. In order to achieve this, they need a large displacement for a small GM. This creates a long natural period of pitch/roll. The restoring force, is low and this is created by the low WPA. The large WSA is related to the displacement but the part you're missing, is the significant increase in drag that this creates.

    Secondly, the faster you go, they suffer from the Monk effect and begin to destabilise in pitch. Reason, their low righting moment.
     
  10. Stephen Ditmore
    Joined: Jun 2001
    Posts: 1,388
    Likes: 44, Points: 58, Legacy Rep: 699
    Location: Smithtown, New York, USA

    Stephen Ditmore Senior Member

    I'm afraid I'm with AdHoc on this, Peter. I wouldn't have any problem with a rule that PERMITS a SWATH, but a sailing SWATH won't win because, as I've said:

    For stability to be maximized the leeward hull will have to support something approaching the entire displacement of the boat when the rig is powered up. (Even in the case of a hydrofoil this will be true at least until the boat is up to speed and the foils take over.) It will need enough waterplane area for this to occur, and since the SWA in SWATH stands for Small Waterplane Area I don't see it as compatible with sailing speed.
     
  11. petereng
    Joined: Jan 2008
    Posts: 581
    Likes: 21, Points: 28, Legacy Rep: 252
    Location: Gold Coast Australia

    petereng Senior Member

    http://en.wikipedia.org/wiki/Sea_Fighter

    50-55 knot swath

    We are talking possibilities here, the foils in the sailing SWATHS case are to control and provide positive or negative righting moment which then becomes nearly unlimited (equivalent to ground effect formula one cars say and why the AC34 rules have restrained the windward foils from sucking). The hulls are to provide bouyancy. Not saying it will work or not it hasn't been done before. Submarines are faster then surface craft and 10 years ago moths couldn't foil. But I'll leave it at this as we are talking about the possible AC35 here. The AC35 could just use the RC44 as it meets the minimum length requirement of the Deed, its not a bad guess why the RC44 is 44 ft long plus it fits in a container. Peter S
     
  12. Ad Hoc
    Joined: Oct 2008
    Posts: 6,199
    Likes: 415, Points: 83, Legacy Rep: 2488
    Location: Japan

    Ad Hoc Naval Architect

    Stephen,

    Sorry for digressing on your thread.

    Peter:

    If you know what a catamaran is, then you would know, this is not a SWATH. It is sales hype. It is simply a long slender catamaran, that is all.

    It has been called a "semi-swath" simply for marketing purposes, just as the term wave piercing hull, great marketing...the hype is believed, all because of a catchy name..
     
  13. petereng
    Joined: Jan 2008
    Posts: 581
    Likes: 21, Points: 28, Legacy Rep: 252
    Location: Gold Coast Australia

    petereng Senior Member

    There is a valuable discussion to be had here in defining what is a "sailing boat" but in terms of what will be done in AC35 it's up to the challenger and defender or the New York Court and I'll leave on that note. Peter S
     
  14. Ad Hoc
    Joined: Oct 2008
    Posts: 6,199
    Likes: 415, Points: 83, Legacy Rep: 2488
    Location: Japan

    Ad Hoc Naval Architect

    Indeed.

    But I'm unclear how this relates to a SWATH?
     

  15. Ad Hoc
    Joined: Oct 2008
    Posts: 6,199
    Likes: 415, Points: 83, Legacy Rep: 2488
    Location: Japan

    Ad Hoc Naval Architect

    Stephen,
    To some extent, this was discussed as noted in this posting here:
    http://www.boatdesign.net/forums/sailboats/perils-edgy-design-offshore-38903-10.html#post476845

    In trying to explain to some, how and why multihulls are the way they are and where the strengths and weaknesses are.
     
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.