Forgot password

Split junk centre of effort

<< First  < Prev   1   2   Next >  Last >> 
  • 28 Mar 2015 00:21
    Quote
    Reply # 3272216 on 3272020
    Anonymous member

    Hello Robert. My AeroJunk is a version of a split-junk sail so I will venture my opinion.

    I looked at your photo and sketch and in my opinion your mast is too far forward to benefit from a Split-Junk sail. If I were in your position I would keep your present sail but replace all the straight battens with wishbone battens. (See February's JRA Newsletter) This will give you more drive and better upwind ability. If you keep the luff haul and move the attachment point on the yard further aft you will be able to balance the helm much more easily.

    Cheers, Paul McKay
  • 27 Mar 2015 19:43
    Quote
    Message # 3272020
    Anonymous member

    I am thinking about replacing the flat sail that came with my boat by a split junk.  I am wondering where the centre of effort will end up, though.  At  https://app.box.com/files/0/f/3345047180/1/f_28035475082 I have a photo of the boat on the left.  On the right there is a transparent outline of the sail, moved to the same relation to the mast as on the photo.  In practice, I have not bothered with the luff hauling parrels, because even when I leave them alone and the sail moves about 50cm forward, so that the first vertical seam is just before the mast, the boat still has a bit more weather helm than I like.

    The yellow sail is an outline of a possible split junk.  It's luff is in the same position to the mast (in white, ignore the yellow mast) as the flat sail when I use it.  So as far as the distribution of the area is concerned, I should be safe from lee helm.  But a cambered sail's centre of effort is supposed to be further forward, so is it likely that I would have a problem?  
<< First  < Prev   1   2   Next >  Last >> 
       " ...there is nothing - absolutely nothing - half so much worth doing as simply messing about in junk-rigged boats" 
                                                               - the Chinese Water Rat

                                                              Site contents © the Junk Rig Association and/or individual authors

Powered by Wild Apricot Membership Software