AC 36 Foiling Monohulls

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

  1. Dolfiman
    Joined: Aug 2017
    Posts: 716
    Likes: 332, Points: 63
    Location: NICE (France)

    Dolfiman Senior Member

    >>> Participants and topics now available and registration is open for those who can come (web site Défi Azimut) :
    • Quentin Lucet, architect - VPLP Design, will present the projects of the firm which has designed the next monohull Charal for Jérémie Beyou (who was 3rd at the last Vendée Globe)
    . Hervé Penfornis, engineer and close collaborator of naval architect Guillaume Verdier, will talk about the latest technological developments, Volvo 60, directly inspired by the Imoca.
    • Anne-Claire Le Berre, research group of the Initiatives-Cœur team, will explain how to develop and optimize an IMOCA of a previous generation.
    • Antoine Mermod, President of the IMOCA will come to decode the changes of the new IMOCA rules and how the class can evolve technically.
    • Matthieu Robert, co-founder of MADINTEC, specialist in electronic and computer developments for racing sailboats, will present the latest innovations in this field.
     
  2. Tink proasail
    Joined: Feb 2013
    Posts: 2
    Likes: 0, Points: 1, Legacy Rep: 10
    Location: Uk

    Tink proasail New Member

    Make it fast a fun by changing the format. In the racing my daughter was doing it was one lap of a short course, each race about 6 minutes 21 kids sailed a total of 60 odd races in 6 hours. I am sure there would be a great short format of races that could be real interesting. With modern graphics highlighting the right of way boat the racing could be accessible to all.
     
  3. sharpii2
    Joined: May 2004
    Posts: 1,839
    Likes: 84, Points: 48, Legacy Rep: 611
    Location: Michigan, USA

    sharpii2 Senior Member

    I envision something that looks like an IOR boat, with a diamond shaped deck plan, allowing a wide Beam and a very narrow WL.

    Foiling boards, which are similar to those on the AC cats will be placed near the extreme Beam on Port and Starboard.

    A relatively large crew, which serves as human ballast, will be on the windward side. They will have to quickly scramble when the boat changes tacks. They may be required to wear or carry water ballast packs as well, making this vessel a 21st century sandbagger.

    I don't see a canting ballast keel as at all practical, as no engine to cant it will be allowed. Having the crew do it will simply take too long to win in a decent tacking duel. The keel ballast is likely to be token at best, to insure the boat does not list severely or capsize while at rest.

    They will probably be no faster than the smaller "open whatever" boats, but will be able to change tacks much quicker.
     
  4. myszek
    Joined: Jan 2013
    Posts: 46
    Likes: 1, Points: 8, Legacy Rep: 22
    Location: Lodz, Poland

    myszek Junior Member

     
  5. schakel
    Joined: Jul 2008
    Posts: 344
    Likes: 8, Points: 18, Legacy Rep: 48
    Location: the netherlands

    schakel environmental project Msc

    I do not agree with you on that one. Just as in the last cup they will be able to store power in batteries is my first guess.
    This energy can be used for the canting keel.
     
  6. tspeer
    Joined: Feb 2002
    Posts: 2,192
    Likes: 156, Points: 63, Legacy Rep: 1673
    Location: Port Gamble, Washington, USA

    tspeer Senior Member

    I would really hate to see the AC go the powered route. They used powered controls in AC33, but that was an anomaly due to the defender throwing out the racing rules regarding stored energy. USA17 was sailed with all manual power and could have raced that way had the defender not gone the powered route. The accumulators used in the AC50s were a necessary safety item to have a rational hydraulic system design, after the AC72 Design Rule took the stored energy restriction way too literally.

    Batteries have an issue in that they can't start off totally discharged. The only way to keep a lid on the stored energy would be to specify a maximum battery capacity and allow the boat to start with that capacity fully charged.
     
  7. tspeer
    Joined: Feb 2002
    Posts: 2,192
    Likes: 156, Points: 63, Legacy Rep: 1673
    Location: Port Gamble, Washington, USA

    tspeer Senior Member

    I think there's a fundamental problem with foiling monohulls in close quarters match racing. In order to foil, you need to have a light weight boat, powered up. To get power, you need beam to generate righting moment. A multihull provides the righting moment within the max beam of the hull(s). Most (the Moth being the rare exception) existing foiling monohulls allow the foils to extend outboard of the beam of the hull. This is manifestly unsafe for match racing - think Ben-Hur style chariots.

    One way around this problem might be to ensure the foils stay within the max beam of the hulls, and give the monohull the beam of a multihull. This could mean a cross between Mark Pivac's Moth design that Brett Burvile sailed in the Perth Moth World's in 2000, and the KZ1 big boat from the 27th AC in 1988.
    [​IMG] [​IMG]

    The Pivac/Burvile Moth configuration was later ruled to be a multihull because the foils gave it two laterally separated waterplanes. There would need to be suitable definitions of "monohull" and "appendage" in the design rule for a foiling, match racing monohull.

    The scows had a similar issue with tunnel hulls.
    [​IMG][​IMG]

    As you stretch the beam and allow foils, at what point does it cease to be a monohull and become a catamaran?
     
  8. Dolfiman
    Joined: Aug 2017
    Posts: 716
    Likes: 332, Points: 63
    Location: NICE (France)

    Dolfiman Senior Member

    [​IMG]

    As you stretch the beam and allow foils, at what point does it cease to be a monohull and become a catamaran?[/QUOTE]

    You are right, IMOCA class also faced this issue and adopted this monohull definition :
    "Monohull: A “monohull” such as that understood in the present rules is defined as a boat:
    - with a single flotation plane at rest or under sail in normal sailing trim.
    - of which hull depth in all transverse sections shall not decrease towards the centreline of the boat.
    For this definition, the hull does not include its appendages (Article C.7 and Section E)."

    Imoca class rules 2017. : https://www.imoca.org/modules/kameleon/getFile.asp?id=687&name=classrulesimoca2017v11.pdf
     
  9. CT249
    Joined: May 2003
    Posts: 1,220
    Likes: 65, Points: 48, Legacy Rep: 215
    Location: Sydney Australia

    CT249 Senior Member

    The IMOCA rule has been pretty commonly used since the first effort to outlaw a Dominion type said something like "the bilges shall be no deeper than the keel". That produced what was essentially a trimaran version of Dominion among the entries for the Quincy Cup in around 1899, so after that the "no decrease" rule was generally adopted.

    Tom, it's interesting that you disagree with stored power. So do I, but would you mind outlining your reasons?
     
  10. Konstanty
    Joined: Mar 2016
    Posts: 76
    Likes: 3, Points: 8, Legacy Rep: 10
    Location: Bydgoszcz Poland

    Konstanty Junior Member

    The energy accumulator can come from wind or water turbines This energy can be accumulated during sailing before the start.
     
  11. CT249
    Joined: May 2003
    Posts: 1,220
    Likes: 65, Points: 48, Legacy Rep: 215
    Location: Sydney Australia

    CT249 Senior Member

    But that's arguably not sailing as we know it, which is using sails rather than turbines.

    That doesn't mean that turbines are bad; it's just that they are so different they are not part of the sport we play in the AC. It's the same as the fact that snooker is not bad, but you don't play snooker in the world billiards championships. Rugby is not bad, but you don't enter the soccer football world cup and start holding onto the ball and running with it.
     
  12. Doug Lord
    Joined: May 2009
    Posts: 16,088
    Likes: 247, Points: 73, Legacy Rep: 1362
    Location: Melbourne, Florida

    Doug Lord Flight Ready

    Worlds first fully foiling (upwind and downwind) keelboat. Light air takeoff in about 5 knots of wind. Upwind foiling in 7-8 knots wind.
    RM is key to any foiler............
    --On an AC boat the racks could stick out a bit further than the "Q" foils probably eliminating hull to foil contact between raceboats while still allowing the Welbourn Q foils to work.


    picture and details from Michi and Hugh Welbourn:
    Quant 23 flying - Copy.jpg
     
    Last edited: Sep 23, 2017
  13. schakel
    Joined: Jul 2008
    Posts: 344
    Likes: 8, Points: 18, Legacy Rep: 48
    Location: the netherlands

    schakel environmental project Msc

    For research reasons: Light batteries will be extremely usefull to develop.
    Can be used in hybrid cars, Boats, planes and so on.
    Always thought one of the reasons for the cup is to be a research platform.
    battery-comparison-energy-density.jpg
     
    Dolfiman likes this.
  14. Konstanty
    Joined: Mar 2016
    Posts: 76
    Likes: 3, Points: 8, Legacy Rep: 10
    Location: Bydgoszcz Poland

    Konstanty Junior Member

    A small wind turbine or water turbine to charge an electric or mechanical acumulator is nothing new on sailing yachts.
     
    fastsailing likes this.

  15. OzFred
    Joined: Nov 2015
    Posts: 402
    Likes: 36, Points: 28, Legacy Rep: 16
    Location: Earth

    OzFred Senior Member

    I think the 80 million automobiles sold each year that can all potentially have electric or hybrid engines are a hugely greater incentive to produce lightweight batteries than a quadrennial sailing competition with half a dozen (extraordinarily expensive) boats. ;-)
     
    schakel likes this.
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.