Lower boom height question

Discussion in 'Sunfish Talk' started by craigtowner1, Jan 13, 2009.

  1. craigtowner1

    craigtowner1 New Sunfish sailor

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    Question:
    I'm new to Sunfish sailing and have a question. I noticed that some boats have the sail rigged higher than others at the aft end. Is there an advantage or disadvantage to having the aft end of the lower boom high or low other than the obvious fact that you won't have to duck as much when the boom crosses the deck ? Does this change the sailing characteristics or cause the boat to react differently ?
     
  2. Wavedancer

    Wavedancer Upside down? Staff Member

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    The Sunfish Bible has much info on this topic.
    In a nutshell, sailors, especially racers, lower the sailplan when overpowered by adjusting the halyard on the gaff. The angle of the boom is also greatly effected by the gooseneck setting. In lighter winds, racers may have the gooseneck 14" from the tack. Moving the gooseneck back to, say 18", brings the boom closer to horizontal. And will lower the sail plan as well, making it easier to keep control in bigger breeze. These settings are individual (weight is a big factor) and you should experiment with what works best for you, under various conditions.
     
  3. beldar boathead

    beldar boathead Well-Known Member

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    For recreational sailing, you will be most comfortable with the front of the boom 12-16" off the front deck, and the gooseneck 20" back from the front. the boom will angle up so you can get under it easily, and the boat will be controllable when it gets windy.

    For racing, you need the sail low to minimize weather helm (google "weather helm" if you need an explanation of that term." for rec sailing, keeping weather helm minimized while allowing for some headroom is most important.

    BB
     
  4. craigtowner1

    craigtowner1 New Sunfish sailor

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    So it sounds like beginners should have the sail low and horizontal for the best control. It seems like the higher the sail is off the deck the more unstable the boat will be.
     
  5. craigtowner1

    craigtowner1 New Sunfish sailor

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    Thanks for the info. I'll try it just like you noted...
     
  6. Wayne

    Wayne Member Emeritus

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    Craig,

    Judging from your statement of being new to sailing I have to ask how your boat is equipped. The typical Sunfish is setup where you can tie the halyard along the upper spar at any location you desire. That is about the only easy adjustment you have available unless the gooseneck has been equipped with a quick release pinch bolt. This enhancement was usually an aftermarket add-on allowing you to fine tune the boom’s fore and aft position without requiring a wrench. The result of making such an adjustment is what I believe you are observing.

    Early setup instructions recommended the halyard attachment point at 7-1/2’ up from the junction of the boom and upper spar. Counting up from the junction this placed the tie-in point between the 7th ad 8th sail clip. With this arrangement the boom sits high above and remains parallel to the deck making ducking during tacks a minimal exercise. The drawback to this boom height is it gives the wind leverage requiring hiking out at lower velocity to keep the boat balanced.

    As Sunfish sailors became more aware of this disadvantage and realized keeping the hull more to an even keel gained them better speed they lowered the boom, literally. Halyard tie-in moved up the spar to a position between the 9th and 10th sail clip. This meant ducking to a greater degree, but for the effort gained better balancing advantage against the force of the wind.

    In addition to lowering the boom by way of the halyard placement, racers, who sometimes sail in heavier winds than the average pleasure sailor, devised a method to lower the boom (reduce wind leverage) even more for adverse conditions. This specialty setup is called the Jens Rig, named after it’s developer, Jens Hookanson.

    Along with increased awareness of the sail height, a complimentary adjustment started to gain attention. Sailing in stronger wind brings into play the issue of weather helm, the tendency of a boat to pull toward the wind due to it’s factory setting for balance between Center of Effort (CE) in the sail and Center of Lateral Resistance (CLR) generated by the daggerboard, hull, and rudder. Among these design elements the CE is the most easily adjustable variable. Moving the CE in relation to CLR requires shifting the boom’s position in the gooseneck. (Despite the popular reference, the gooseneck remains stationary, it’s the boom and its attached sail that’s actually being moved)

    For the standard Sunfish, sail position adjustment requires getting out a wrench and loosening the gooseneck pinch bolt so the boom can slide back or forth to a desired setting. The wrenching task has been made easier with the advent of the quick release gooseneck bolt. Utilizing this device allows adjustment without tools nearly anytime, even on the water. Sailors who fine tune the helm of their boat in this way often mark the boom in one inch increments for the region of adjustment. A result of repositioning the sail sometimes puts the boom at an angle relative to the deck.


    Further Reading:

    The latest Sunfish rigging guide from Laser Performance (Shows both the fixed and adjustable gooseneck bolts)
    http://www.laserperformance.com/main/images/stories/pdfs/Sunfish/Sunfish(US).pdf

    The Sunfish Bible by Will White (explains more about sail height, the Jens Rig, and helm adjustment)
    [ Available for around $30 from most Sunfish dealers and the Sunfish Class.org ]

    What should I do with [the] sail when the wind increases? (from this form’s FAQ)
    http://www.sunfishforum.com/content.php?a=faq#What should I do with sail when the wind increases
     
  7. beldar boathead

    beldar boathead Well-Known Member

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    You can easily adjust the gooseneck even without an quick release. Just use a wrench, loosen it up, move it where you want it and tighten it back up. For recreational sailing, you can, in the words of Ron Popeil and the Showtime Rotisserie Oven, just "set it and forget it!" For recreational sailing, a quick release gooseneck bolt is just unneccessary.

    BB
     
  8. craigtowner1

    craigtowner1 New Sunfish sailor

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    Thats fot the valuable and detailed explanation.
     
  9. winever

    winever Member

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    Awesome post Wayne! I'm new to the Sunfish and that explanation just gave me what I needed to know, why and how it came about. Many thanks, now it just needs to warm up a little. Regards, Winever.
     
  10. Wayne

    Wayne Member Emeritus

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    Winever,

    You would probably both enjoy and find benefit in reading The Sunfish Bible. It’s the quintessential manual of Sunfish requisites all the more sophisticated sailing tactics are built upon, not to mention a wealth of historical information for any Sunfish buff.

    Check the Forum’s dealer sponsors or look in the Forum’s FAQ to obtain a copy. Do not go to Amazon, B&N, and the like, the book seller's price guide they consult appears to contain a gross error regarding this publication.

    Good way to pass the time until warmer weather arrives.
     

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