Why is the Balestron rig fractional?

Discussion in 'Sailboats' started by misanthropicexplore, Feb 5, 2019.

  1. misanthropicexplore
    Joined: Apr 2018
    Posts: 61
    Likes: 3, Points: 8
    Location: Upper middle Missouri River

    misanthropicexplore Junior Member

    Balestrons are always fractional rigs, at least on the internet, no matter what the scale, from tiny models to 20 meter yachts.

    Wikipedia says fractional rigs (in conventional installation) are generally for performance sailboats, and gives this page as a reference "Introduction https://web.archive.org/web/20110907052856/http://www.jboats.com/j30/j30intro.htm" Why would a fractional rig be high performance? Couldn't you use a masthead rig with a smaller foot on the jib to do the same thing? Why does a small jib create less drag in a conventional setting, and does that have anything to do with it on a Balestron?
     
  2. Earl Boebert
    Joined: Dec 2005
    Posts: 375
    Likes: 46, Points: 28, Legacy Rep: 302
    Location: Albuquerque NM USA

    Earl Boebert Senior Member

    Well, on models at least, if you go above a 30% or so jib you'll find the rig won't swing reliably to the downwind position in lighter air. Dunno about full-size boats.

    Cheers,

    Earl
     
    Doug Lord likes this.
  3. jehardiman
    Joined: Aug 2004
    Posts: 2,477
    Likes: 198, Points: 63, Legacy Rep: 2040
    Location: Port Orchard, Washington, USA

    jehardiman Senior Member

    The most likely reason is the typical reason for fractional rigs...mast bend. If you need to flatten the sails, having a masthead jib stay would cause mast inversion (tip forward) where as a fractional jib stay will pull the center of the mast forward flattening the main.
     
  4. Blueknarr
    Joined: Aug 2017
    Posts: 688
    Likes: 110, Points: 43
    Location: Colorado

    Blueknarr Senior Member

    Jehardman,
    I disagree. Increasing backstay tension on masthead rigs will induce mast bend and decrease headstay sag. It us the ratio of bend and sag uptake that varies between fractional and masthead rigs. If mast height and deck layout remains the same; as the forestry lowers along mast, bending increases to sag uptake.
     
  5. jehardiman
    Joined: Aug 2004
    Posts: 2,477
    Likes: 198, Points: 63, Legacy Rep: 2040
    Location: Port Orchard, Washington, USA

    jehardiman Senior Member

    Blueknarr, the Balestron rig is generally stayless in small sizes or just side stayed when large . There is no headstay or backstay per say, only a jib stay from the forward end of the boom and generally fractionally rigged. On smaller rigs there is sufficient strength in the sail that main haulyard and jib haulyard tension is suffice to induce mast bend, on larger or loose-footed rigs there is a running backstay led to the end of the boom to tension against the fixed jib stay in classic fractional rig fashion. <shrug>
    [​IMG]
     

  6. sharpii2
    Joined: May 2004
    Posts: 1,875
    Likes: 87, Points: 48, Legacy Rep: 611
    Location: Michigan, USA

    sharpii2 Senior Member

    Having built a rig similar to that when I was a teen, my guess is that the jib must be smaller because the main provides the luff tension. You can have a bigger jib with a shorter luff only by going with a shorter one. Mine went up to the masthead but extended past the mast only a short distance and had very little sail area when compaired to the main. (see attachments).
     

    Attached Files:

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.