AC 36 Foiling Monohulls

Discussion in 'Sailboats' started by OzFred, Sep 13, 2017.

  1. Doug Lord
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    Doug Lord Flight Ready

    Long ago Option 3 renders by Sean Langman:

    LSS_7_jpg_sml.jpg

    langman1_sml 2.jpg

    langman3_sml 3.jpg
     
  2. schakel
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    schakel environmental project Msc

    ^Will be extremely hard to sail. Can't imagine how to find balance with that boat.
     
  3. BlueBell
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    BlueBell Ahhhhh...

    Imagine what was said about Moths!
     
  4. michaeljc
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    michaeljc Senior Member

  5. schakel
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    schakel environmental project Msc

    I like that story about the lone wolf team. A team is never alone but that's a detail.
    Taking home the silverware by Peter Burling and Grant Dalton is as good as it gets.
    silverware.PNG
    peter burling cup.jpg
    Now Peter will sail saterday away with team Brunel around the world to pick -up another piece of silverware.
    Volvo Ocean Race - Around the World Cup.jpg
    Peter Burling http://www.volvooceanrace.com/en/people/640_Peter-Burling.html
     
  6. CT249
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    CT249 Senior Member

    Actually one of the first things that was said about racing foiling Moths was that they were too stable, although that was the wingtip-foil type. But I don't recall anyone who was familiar with Moths saying they were impossible to sail, as people do with these designs. And the Moth is a completely different type of boat on a completely different scale and completely different level of difficulty.

    Not only has Sean given up on the tri foiler idea apparently, but last I heard he's given up on canting keels.
     
    Last edited: Oct 19, 2017
  7. Doug Lord
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    Doug Lord Flight Ready

    NZAC, version two foils:
    NZAC Version Two Foils (TC) 002.JPG

    For reference version one foils("Q" foils):
    NZAC ONE     9-25-17  dl 002 - Copy.JPG

    NZAC SAILPLAN, version 1,  9-29-17 004.JPG

    Disregard foil position for version two foils:
    NZAC revised   9-7-17 003.JPG

    Tentative specs:
    Based on these calcu-guestimates:
    A) At 90 degrees the force holding the boat there is 171,926 ft.lbs.
    The force trying to right the boat is 483,800 ft.lbs.
    1-keel weight 19782 lb @ 20'
    2-buoyancy from pod-4608lb @20'
    -- "A" means that the boat is self-righting from a knockdown.....
    -
    3- Wing mast 115' above deck
    4- SA=3191 sq.ft. incl wing mast
    -----
    B) Weights----
    1) hull weight-8572 lb
    2) keel weight 19782lb
    3) rig weight 2915lb
    4) crew weight 1900lb
    5)TOTAL DISPL.= 33168 lb
    -----
    C) RM on Foils:
    1) HM at 59' with 2.5lb/sq/ft. pressure= 470,672 ft.lb.
    2) RM, boat slightly heeled, mast vertical=569,418 ft.lb.
    -----
    D) Foil Loading one main foil in the water supporting 80% of the load=
    18' X 2.5' chord foil fully immersed=589lb/sq.ft.
    -----
    E) Boat may need canting keel NOT for ultimate RM but to get started. Needs much more study but all in all probably has great potential IF the target weight can be met.
     
  8. OzFred
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    OzFred Senior Member

    Absolutely not.

    The top diagram is a trimaran. If those design concepts are taken to their logical conclusion, the keel and main hull become redundant and the result is a catamaran.

    The second is also a trimaran, would be slow and likely be beaten by a non–foiling mono in most conditions. The Quant–style foils are intended for easy foiling, not outright speed. I'd expect a Quant 23 to be beaten by an i14 or even a 16 foot skiff around a windward/leeward course. Large monohulls with lateral foils have been tried (quite extensively now) on boats that have invested significant funding in design and research, but they have not proven to be a significant performance benefit.

    Despite the hype over the foiling Mini 650s, the first leg of the 2017 Mini Transat was won by Ian Lipinski in FRA 865, a non–foiling boat.

    In contrast, the foiling Moth and AC catamarans (and lesser extent A Class) were so obviously superior that there was no question of whether or not to go foiling. That level of competitive advantage has not been developed for large monohull boats yet.

    The conundrum for the America's Cup is that it's fundamentally a boat design competition to see who can build the fastest boat. However, that leads to boring racing as it doesn't matter how good you are at match racing, a clearly faster boat will nearly always win. So the rules try to make the boats as similar as they can without making them identical so as to get close racing. But even then, one boat usually ends up clearly faster and wins easily.

    What we know of the next AC boat is that designers won't have much time (about 12 months) for design and build of the first boat, nor will they be able to do tank or wind tunnel testing, so the boats will necessarily be conservative and evolutionary, not revolutionary. Hopefully the initial concepts being released to key stakeholders in late November will also be released publicly.

    The end of November seems a long way off…
     
  9. Doug Lord
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    Doug Lord Flight Ready

    The buoyancy pods on NZAC would not be designed to support any proportion of the boats displacement when it is moving at any speed-they are only there to help the keel right the boat from a knockdown. They would never be sailed "on". Not a trimaran.
    The foils on version two are similar to the UptiP foils used successfully on the SuperFoiler which is a trimaran.

    SuperFoiler using UptiP foils on her amas-the foils are similar to the NZAC version two foils. The amas have nothing in common with the NZAC buoyancy pods other than being on the outside of the boat and supporting the foils.
     
  10. OzFred
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    OzFred Senior Member

    As you well know, that configuration has already been judged a trimaran when applied to a Moth which had minimal (possibly no) buoyancy in the wings. The addition of structural buoyancy pods puts the issue beyond doubt.

    The F101 is a similar concept and is called a trimaran by the designers. I can't see how comparison with the SuperFoiler trimaran helps your case.
     
  11. Doug Lord
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    Doug Lord Flight Ready

    NZAC is not governed by the Moth rules or by any existing rule. The F101 trimaran is not even close to NZAC which is a monohull.
     
  12. Doug Lord
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    Doug Lord Flight Ready

  13. OzFred
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    OzFred Senior Member

    Blue Arrow has already been mentioned in post 42. Whether it was a mono or multi by any particular criteria wasn't determined given that it wasn't allowed to compete. Further, the foils didn't lift the hull out of the water, they were just for stabilisation.

    Given that in the 1988 series the Kiwis challenged in an oversized skiff and were soundly beaten by the US in a catamaran, whether Blue Arrow was a mono or multi was moot. By 2004 the Moth guys were calling a similar fully foiling configuration a trimaran, so there is serious doubt in the minds of some very knowledgeable people who design, build and run a highly successful international foiling class. Of course the Kiwis are at liberty to determine otherwise, we'll just have to wait and see what the initial concepts reveal.
     
  14. Doug Lord
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    Doug Lord Flight Ready

    Quote from AC History ( Blue Arrow http://www.americas-cup-history.at/english/blue.htm ) :

    Peter de Savary reached the LVC Challenger Final in 1983 with his self-financed Victory 83 campaign but lost then against Australia II. At the AC 1987 he did not take part but placed a challenge for the next Cup with an outstanding monohull. This was the hydrofoil-stabilized "Blue Arrow".It was about the size of Conner's catamaran Stars & Stripes, but had a single hull that was as narrow as a canoe. It was launched officially on 20th July 1988, 90 days after the start of design.
     

  15. CT249
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    CT249 Senior Member

    And on what authority can AC History decide what type of boat any craft is?
     
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