Partly Clubbed Jib (Sonder Class)

Discussion in 'Hydrodynamics and Aerodynamics' started by Earl Boebert, Jun 12, 2012.

  1. Earl Boebert
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    Earl Boebert Senior Member

    I've been studying Sonder boats and building a "Sonder-inspired" 36" model. The bulk of these boats used a short jib club/boom that ran from the clew of the jib along about 80% of the foot, with the rest of the foot loose to the tack. I've attached the sail plan I'm working from where the club is clearly visible. The picture of the German boat "Angela" shows it clearly, along with the effect on the shape of the jib. Even Nathanael Herreshoff did this on his Sonder "Bibelot."

    I can't for the life of me understand what the reasoning was behind this feature. Anybody have a clue?

    Cheers,

    Earl
     

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  2. philSweet
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    philSweet Senior Member

    It reduces the hook on the bottom of the jib. I've fitted them to several boats as an easy single hander mod. Small overlap sails can be made self tending with biggish clubs like that. Changes the location of the jib block which may free up space in the cockpit as well. In boats that don't have a jib track, a club allows you to fiddle with the lead angle to get the best all around performance. I like them a lot for low control effort sailing. Gust response can be adjusted by changing the sheet attachment at the club.
     
  3. philSweet
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    philSweet Senior Member

    Looking at the linesplan, I think the point is to run the jib on a jib traveller. This allows self tacking without any sheet adjustment. It works like a champ.

    also, you can store the clubbed jib on deck ready to go in a way that you just can't do with a loose footed jib. I usually had a few hanks near the bottom and flew the top half loose. I could drop the sail, pull the head in towards the mast and stopper the sail to the club and walk away in ten seconds. Handy for cutter and slutter rigs.
     
  4. Earl Boebert
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    Earl Boebert Senior Member

    Thanks for the explanation. But why not a boom along the whole foot of the jib, attached just at clew and tack like a model yacht?

    Cheers,

    Earl
     
  5. gonzo
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    gonzo Senior Member

    These boats were designed with cotton sails. They were cut flat and then stretched into a proper shape. However, they were not as rigid as modern cloth. The partial boom lets the leading edge curve more and the aft section flatten.
     
  6. Earl Boebert
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    Earl Boebert Senior Member

    Here's the 36" LOA Sonder model that prompted the question on her first sail. Photos by Jay Eschenberg.

    Cheers,

    Earl
     

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  7. FAST FRED
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    FAST FRED Senior Member

    "But why not a boom along the whole foot of the jib, attached just at clew and tack like a model yacht?"

    By locating the tack of the sail back from the stay ,(usually to a pedestal) the jib will flattened as it is hauled in.

    But the jib will gain fullness as the sheet is released, the further off you sail the fuller it gets.

    Self tacking with nice sail shape is the goal.

    Downside is the limited sail area ,no overlap and the chance of ankle bashing if working on the foredeck.

    FF
     
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