Foiling boats weight sensitivity?

Discussion in 'Hydrodynamics and Aerodynamics' started by Mikko Brummer, Jun 15, 2021.

  1. Doug Halsey
    Joined: Feb 2007
    Posts: 640
    Likes: 212, Points: 53, Legacy Rep: 160
    Location: California, USA

    Doug Halsey Senior Member

    I'm embarrassed that I can't find the inputs for this case, and I am skeptical about this result. Not about the idea that the righting moment advantage could outweigh the drag disadvantage in many cases. I would have no problem believing it for a wind speed of 20 knots, or even 15, but 10 just seems unrealistic. I'll have to revisit the question when I get a chance.

    Meanwhile, I'll just say it represents some possible overpowered foiler, not specifically a Mach2.

    And yes, the VPP accounts for the windward heel.
     
    Skyak likes this.
  2. revintage
    Joined: Nov 2016
    Posts: 414
    Likes: 101, Points: 43, Legacy Rep: 10
    Location: Sweden

    revintage Senior Member

    Back to the original subject about foiling boats and crew weight! I suppose we are talking about sailing in winds where the boat is foiling. It would be interesting if there where some statistics from something like Waszp where all boats are equal. The graph about foiling moths I presented in the beginning of the thread shows a tendency to favour lighter crews. If everything else is alike the added incidence needed for a heavier crew would add some drag. But on the other hand a heavier sailor could trim the sail for added power to compensate and have added righting moment at hand. A VPP might tell us what to expect, but statistics from foiler championships will probably give more info. Maybe the Nacra 17 class have collected some data?
     
  3. Doug Halsey
    Joined: Feb 2007
    Posts: 640
    Likes: 212, Points: 53, Legacy Rep: 160
    Location: California, USA

    Doug Halsey Senior Member

    That figure seems to only be showing the back half of the fleet. Or am I misinterpreting?
     
  4. revintage
    Joined: Nov 2016
    Posts: 414
    Likes: 101, Points: 43, Legacy Rep: 10
    Location: Sweden

    revintage Senior Member


  5. FoilAddict
    Joined: Mar 2021
    Posts: 5
    Likes: 0, Points: 1
    Location: Maui, Hawaii

    FoilAddict Junior Member

    My guess is aero and wing design matter more than weight. Aero already makes a huge difference in the much lower speeds (15-25kn) I do wingfoiling. When racing wingfoiling, the difference between squatting and standing can win you an upwind leg. What also helps is using the mast for upwind lift, which levels the board and decreases aero drag. A bigger rider could need a bigger board or kite, and is probably bigger themselves, increasing the aero drag. Every foil design also has an optimum lift coefficient for max l/d; different rider weights or sail sizes will change the load on a one design foil and thus Cl of the wings.

    I did some racing against Kai Lenny wingfoiling, he’s 50lbs lighter than I am and the winner was the one who had the best fitting gear, sailing skill (tacks, reading shifts, sailing correct angles), and luck.

    Predicting this will be really hard without more information on the exact wing, sail, and board design, the rules of the race, and loads on the rider’s body. As for a general sailing trend, scaling up seems to make things faster.
     
Loading...
Similar Threads
  1. alan craig
    Replies:
    5
    Views:
    1,207
  2. Alan Cattelliot
    Replies:
    75
    Views:
    6,940
  3. tlouth7
    Replies:
    16
    Views:
    3,461
  4. Iridian
    Replies:
    11
    Views:
    2,913
  5. Doug Lord
    Replies:
    0
    Views:
    1,427
  6. Doug Lord
    Replies:
    1
    Views:
    2,793
  7. Doug Lord
    Replies:
    40
    Views:
    11,973
  8. ToMy
    Replies:
    163
    Views:
    14,323
  9. Tristan perry
    Replies:
    12
    Views:
    3,115
  10. seandepagnier
    Replies:
    16
    Views:
    3,319
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.