Converting a Compac 27 to Junk Rig - New Project

  • 16 Dec 2015 18:46
    Reply # 3701969 on 3698522

    Hello Mark, I see our messages appeared almost simultaneously, and apologies for drifting slightly off topic.

    Most of the sailing season this year has been spent in converting Branwen, a Wylo 32 design, from gaff cutter to junk. First hoist of my home made sails, shown here, was on September 1st. Sea trials commenced the day after and concluded after a Biscay crossing to Spain, in conditions ranging from glassy to near gale. I'm very happy with the rig, which I've found to be well balanced, close winded, fast and, above all, easy to handle. The sails are made of polyester sailcloth, using Arne Kverneland's master sail patterns for the design. You'll find these under Junk Information, in his Public Domain files.

    Conversion work started on April Fool's day and took exactly 6 months of full time work. I've submitted an article about the job, which should appear in the next issue of the JRA magazine.  

  • 16 Dec 2015 18:23
    Reply # 3701953 on 3698522

    Yes Arne, shortening the batten parrels is on my to-do list, although I expect an increase in friction to result. (I may try Shemaya's idea of sheathing the parrels with spiral cable wrap). 

  • 16 Dec 2015 18:20
    Reply # 3701949 on 3701616
    Deleted user
    Asmat Khan wrote:

    My schooner Branwen has a vertical mainmast and the foremast is raked forward 6 degrees, which helps to keep the foresail quiet: gravity tends to swing it outboard. 

    Asmat,

    Thank you for joining the thread. Branwen is a sturdy looking craft! I really like the choice of sail color. I see you have had a JR for about a year now. Were you able to sail her much since her conversion? How do you like your rig after a season?

    Cheers!

    Last modified: 16 Dec 2015 18:26 | Deleted user
  • 16 Dec 2015 18:15
    Reply # 3701938 on 3700683
    Deleted user
    Graham Cox wrote:

    Positioning the mast is easy.  First draw your sail plan, then superimpose it over a drawing of the bermudian sail plan so that the centre of effort of both is the same, or the junk's CE is slightly further forward perhaps.  The mast position should be about 10 to 15% abaft the luff of the junk sail.  I'd recommend reading PJR before making any firm decisions, to build up some theoretical knowledge.

    Graham,

    Thanks for this. I will try to find a copy of the PJR to get some more info. I am not sure, however, that I will be able to design my own sails and place the mast, etc. did you do the design and build of Arion's rig? If so, can you share about how long it took to gain the knowledge and confidence it took to cut a hole in the deck of Arion? If you made the design and rig and sails, etc yourself, can you tell me about how long from conception to completion it took?


    I apologize for the number of questions, but I am beginning to realize how much of a "Do It Yourself" project converting to a JR would be. I am starting to feel a bit like Alice down the rabbit hole!


    Thanks!

  • 16 Dec 2015 17:38
    Reply # 3701855 on 3698522
    Anonymous member (Administrator)

    Asmat’s experience with batten stagger on a vertical mainmast and forward-raked foremast is interesting.

    On the foresail, I guess the mast simply grabs the batten parrels as the sail comes down and gently leads the battens a bit aft as they stow on the boom.

    Now I have had a closer look at the mainsail of Asmat’s Branwen: This sail is very similar to my sails and I would therefore suspect that this is what happens as Asmat reefs the sail.

    • ·         With the cambered panels (=no diagonal strength) the battens will shift forward as they are about to land on the boom, known as negative batten stagger.

    • ·         As long as the halyard still pulls forward and the batten parrels are long, this will continue as more panels are lowered.

    • ·         The result is that the boom will protrude and the sheets will get caught when raising the sail again.

    This is how I have solved the problem on my boats (Johanna, Broremann and Frøken Sørensen), all with vertical masts:

    • ·         During construction of the sail, I cut off the clew corner and shorten the boom 4-5%, compared to the rest of the battens.

    • ·         When rigging the sail, I make the batten parrels semi-short, that is, just long enough to keep friction tolerable when hoisting and lowering the sail.

    • ·         When taking the first reef, the sail tends to move forward about 4% of the boom, but thanks to the shortened boom, the boom will not protrude from the reefed bundle.

    • ·         As I reef more panels, or dump the whole sail, this happens: The interaction between the semi-short batten parrels and mast  now gently takes over and leads the sail down without further forward movement (negative batten stagger).

    Asmat, could I suggest you try attaching the aft end of the mainsail’s battenparels one slot forward of today’s position (maybe except on the two top battens)?

    Cheers, Arne

     

  • 16 Dec 2015 16:03
    Reply # 3701616 on 3698522

    My schooner Branwen has a vertical mainmast and the foremast is raked forward 6 degrees, which helps to keep the foresail quiet: gravity tends to swing it outboard.

    An interesting by-product: my sails have 6% camber and consequently the mainsail suffers from negative batten stagger: the battens drift forward as the sail is reefed or furled. This does not occur with the foresail, which, having a vertical luff, has more balance at the foot than at the throat. It always reefs and furls neatly, with positive batten stagger. 

  • 16 Dec 2015 09:38
    Reply # 3700683 on 3698522

    Hi Mark,

    Arion's mast is also raked forward by three degrees. It was not uncommon on Chinese junks, and many yacht schooners rake their foremasts also.  I did it because it has the advantage of holding the sail out when the sheet is well eased on a broad reach or run, especially in light weather, and because I wanted to move the CE a little further forward from the position it would have been with a vertical rake.  My mast partners could not go any further forward.  In Practical Junk Rig (PJR, a good investment for a junk sailor) Hasler and McLeod recommend a vertical mast.  Either is good.   Raking the mast aft is not, as the weight of yard and battens will make the sail swing inboard in light conditions.  In a swell, they do crash around sometimes, but in smooth water, a vertical or forward rake will hold the sail out and the boat will ghost downwind in the lightest breath of air.

    Positioning the mast is easy.  First draw your sail plan, then superimpose it over a drawing of the bermudian sail plan so that the centre of effort of both is the same, or the junk's CE is slightly further forward perhaps.  The mast position should be about 10 to 15% abaft the luff of the junk sail.  I'd recommend reading PJR before making any firm decisions, to build up some theoretical knowledge.

    Your final decision will be to decide what kind of junk sail you want (there are a few options, though I favour the "Arne modified" Hasler McLeod sail) and whether it is to be flat-cut, cambered, hinge-battened etc.

  • 15 Dec 2015 22:35
    Reply # 3699996 on 3698522
    Deleted user

    Hi there Annie,

    Thank you for the reply. I did not know that raking a mast forward was an option on any rig.

    You say it works well, of which I have no doubt, but do you find that the forward rake of the mast induces any undesirable effects? I don't presume to know what those effects might be, though. :)

    Raking forward might be an option to save the berth. I can deal with having the mast right at the head of the berth, I believe.

    How did you find where the mast could be mounted and raked forward? Perhaps my question is more to the point asking how does one figure out mast placement, rake, etc. on their own boat?

    Also, Fantail looks to be a fine boat. I like the implied roominess of the cabin allowed by the raised flush deck.

    Thanks again!

  • 15 Dec 2015 21:03
    Reply # 3699885 on 3698522

    The great price of Arion's conversion was that I had to give up the V berth.  I used to love lying with my head in the bows under the open forehatch on hot nights, though I had to remember, when I woke up, not to sit up quickly or I'd bang my head.  After conversion, I ended up with two berths, divided by the mast, but I always touched the mast when I rolled over, which woke me up.  And in winter the aluminium mast is cold!  I could have insulated it with some soft padding, but there really wasn't enough space left.  I had two seats just aft of the berths, forming a tiny saloon, and I modified these to be the same height as the berths and moved the berths aft, so that only my feet were alongside the mast.  Then I made the saloon table lower to form part of the bunk and regained a double bunk of sorts, albeit one with a mast near the foot of the bunk.  It is a bit like having your dog sleeping on the bed!

    Now I have to make up the bunk every night before I sleep, but I have developed a quick and lazy way of doing that.  Wouldn't do for the Queen, as the English say, but good enough for a scruffy bachelor.  Life is a series of compromises, as are boats!

    Last modified: 15 Dec 2015 21:07 | Anonymous member
  • 15 Dec 2015 19:38
    Reply # 3699747 on 3698522
    In order to keep my V-berth, I put the foot of the mast at the head of the bunk and gave the mast a 6 degree rake, as you can see by looking in the Member Photo Albums in my profile (just click on the link under my name to get there).  It not only works perfectly well, but I also like the look of it.  Fantail is 26ft long - not a dissimilar size to your boat.
    Last modified: 15 Dec 2015 19:39 | Anonymous member
       " ...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