Yard Class ( proposed sailboat class)

Discussion in 'Sailboats' started by sharpii2, Jan 9, 2015.

  1. Richard Woods
    Joined: Jun 2006
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    Richard Woods Woods Designs

    my apologies, you say "rig height" so one assumes you mean mast height, actually you mean luff length

    RW
     
  2. sharpii2
    Joined: May 2004
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    Location: Michigan, USA

    sharpii2 Senior Member

    No apology needed.

    The real reason I have Rig Height at all limited is to limit Hull Length.

    Sounds pretty bass ackword, I'm sure, but I think it's a workable strategy.

    A 6.0 m boat would only be allowed a Rig Height of just 2.0 m, which is just slightly more than 6.5 ft.

    Such a boat would most certainly be doable, but it would have at least two masts and a very low aspect ratio sail plan.

    It wouldn't point as well as a shorter boat with a taller rig, but it may well be faster on a broad reach.

    But a boat that is too short will be allowed a Rig Height that is too high for it to handle well. That is why I predict boats would end up being 4.5 m to 5.5 m long, with an average Hull Length of 5.0 m.
     
  3. sharpii2
    Joined: May 2004
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    sharpii2 Senior Member

    Not really. I see all three gentlemen sitting on the rail.

    Limiting Length and Beam, without limiting SA, will lead to this result.
     

  4. sharpii2
    Joined: May 2004
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    sharpii2 Senior Member

    Some tweaking

    I have decided to tweak the rules a little bit.

    I have decided to limit the depth of 'Whales, Guards, and side Centerboard, Side Dagger board, or Lee Board Staples' to 7.62 cm (in paragraph C.) Originally they had no depth limit. And by fairing them into the hull, one could effectively increase the Beam.

    I have decided to reduce the Rig Height plus Hull Length limit from 8.0 m to 7.01 m (in paragraph E.). 8.0 m is just too generous. It will produce very long hulls, as well as a lot of confusion.

    I defined the word 'appendage' to mean any immersed region of the hull that is not at least as wide as it is deep, for ballast purposes (in paragraph G.). This was done mainly to prevent very narrow and deep Hull sections that can be filled with ballast, because they are counted as being a part of the Hull itself, and not being an appendages.

    The edited rules in their entirety are posted below.

    First, I'd like to make a few more comments in defense of this idea.

    Limiting the Beam, without allowing hiking is the heart of this concept. This will require the boat to rely almost entirely on form stability for its sail carrying power.

    It will also pretty much mandate the crew being placed low in the boat, where their weight actually helps improve the range of stability, rather than subtract from it, as in more conventional racing dinghy classes. Such, I hope, will prevent violent capsizes, where the crew will be dumped and the boat turtled.

    Having the crew low in the boat means that, in order to shift their weight to windward at all, the cockpit will have to be entirely open, with no side decks at all. This will mean that the cockpit will quickly fill with water, as the boat capsizes, so will tend to just lay over, rather than flip.

    Closed Bow and stern compartments can provide emergency flotation, plus some righting moment, as their Centers of Buoyancy will tend to be higher than the crew(s) center of gravity. Plus some more buoyancy can be packed into the 7.62 x 7.62 cm Whales.

    The idea of tying the Rig Height to Hull Length came from reading about what happened to the Square Meter classes. With no limit on either Hull Length or (it appears) Rig Height, the rigs got taller and taller, and the Hulls got longer and longer. It would be interesting to see what would have happened if they had a Sum Rule similar to mine.

    YARD CLASS

    (A Sum-Rule racing class)


    A.) BEAM to be limited to 3.0 ft ( 91.5 cm).

    B.) BEAM to be measured between furthest points of outer hull skins.

    C.) Whales, Guards, and Side Center Board or Side Dagger Board staples can extend up to 3.0

    inches (7.6 cm) past this maximum Beam, on either or both sides, providing none of these are more than 3.0 inches (7.62 cm) deep.

    D.) Crew must sit at least 6.0 inches (15.2 cm) below the lowest point of the shear.

    E.) Rig Height, measured from highest point of the sail(s) to the lowest point of the sail(s), plus the Hull Length, must not exceed 23 ft, (7.01 m). ( Hull Length + Rig Height = or < 7.01 m )

    F.) Hull Length is measured between two vertical lines, and includes any platforms or appendages, except rudders. It does not include spars.

    G.) No External Ballast (Ballast outside the Hull Envelope), other than the minimum needed to keep appendages submerged, is allowed. Any region of the submerged Hull Envelope, that is deeper than it is wide, will be considered to be an appendage, for ballast purposes.

    H.) Internal Ballast (Ballast inside the Hull Envelope) can be water, stones, sand, or gravel only. No metal ballast is allowed.

    I.) Appendage depth, measured from the Load Waterline, is not to exceed 3.0 ft. (91.5 cm)

    J.) Emergency Flotation, adequate to keep the boat level and the lowest point of the shear and/or ‘Board Slot(s)’ 3.0 inches (7.6 cm) above the water, when the boat is swamped, must be provided.

    K.) Sails to be made out of ’poly-tarps’ only.

    L.) Specialized down wind sails are not allowed.

    M.) Spars to be made of aluminum, steel, or wood only.
     
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