Converting a Compac 27 to Junk Rig - New Project

<< First  < Prev   1   2   3   Next >  Last >> 
  • 04 Jan 2016 22:36
    Reply # 3739357 on 3698522
    Deleted user

    Mark

    could the mast not go a little forward of the water tank, just about where the vee-berths meet?

    Chris

  • 04 Jan 2016 21:34
    Reply # 3739271 on 3698522

    Mark, I suggest you read this thread

  • 03 Jan 2016 23:11
    Reply # 3737570 on 3698522
    Deleted user

    I went out to the boat today and tried to visualize where the mast would have to be on the boat. It looks like I might have some real challenges in the cabin if I am to convert to a junk rig. There is an integral water tank that begins just about where the forward part of the cabin trunk meets the deck. There is a hatch at the forward top of the cabin trunk into which I could build the mast partners, but I believe that would block ingress/egress in the V-berth cabin area. The current placement of the compression post is just about the only place a mast could go without pretty major changes to the cabin. 

    I know that with almost all things boating, there is compromise and that each owner must make their own choices, but I would like to ask this forum for a little more guidance. Can the junk rig mast be located very nearly where the original mast is placed on the Compac 27? If that would put the CE too far aft on a "normal" junk rig, can more to the sail go forward of the mast to give more balance? 

    I apologize for not having "done my homework," but I really want to make sure this is doable within the confines of what I can do before I put too much money into it. Right now, I don't see a way forward to conversion, but I really, really, REALLY want to. Help, please?

    Thanks in advance!


    Last modified: 04 Jan 2016 00:02 | Deleted user
  • 18 Dec 2015 21:23
    Reply # 3709303 on 3701938
    Mark Hazel wrote:
    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!


    I was fortunate to have a sistership, Minke, that had already been junk rigged and to have sailed aboard.  I had a copy of Minke's sail plan, but having sailed aboard Minke, I knew that Arion, under bermudian rig, had better helm balance.  I superimposed the junk sail plan over my bermudian sail plan and discovered that my CE was 300mm further forward than Minke's.  Because I needed to place the partners in the same place as Minke, I raked the mast forward by three degrees, which achieved this effect.  Of course that means the CE moves aft when reefing, but one would have to be deeply reefed for it to be an issue, and when the wind is blowing hard, I find I can ease the sheet more, almost feathering the sail, and still have heaps of drive to windward.  Off the wind I just keep reefing until the weatherhelm eases sufficiently for the self-steering to work.  It takes very little sail area to drive the boat downwind.

    It took about two days to cut and weld the new partners and mast step in place and another week to paint.  Without looking at the structure of your boat I cannot say what needs doing, but working with plywood, epoxy and glass is relatively straightforward.  I bought an alloy mast, yard and battens and spent a couple of days riveting saddles to them etc, and had a mast cap manufactured by an engineering shop.  I had a sail made for me.  You can make you own sail if you have a floor big enough to spread it out on, as so many in the JRA have successfully done.  Given the dramas with getting sailmakers to make junk sails to the right specifications, it makes sense.

    Time frames are hard to pin down, it depends on how quickly you work and how much time you have available (weekends or full time?).  I estimate I spent about two months full time on the project.  Annie's estimate of 50 hours to build a sail matches the experience of others I have spoken to.



    Last modified: 18 Dec 2015 21:25 | Anonymous member
  • 17 Dec 2015 19:22
    Reply # 3704417 on 3698522
    Anonymous member (Administrator)

    The Compac 27
    surely looks roomy and comfortable inside. If you find that she steers well enough, even when heeling 20 – 25 degrees, then go ahead, no problem. However, if you run out of rudder frequently with the Bermuda rig in squally winds, then you will also do so with a junk rig. However, a junkrig (JR) is actually helpful here as it lets you reef so fast (and often) to keep heel under control.

    The reason for me focusing on this, is that I know that many sailboats with a lot of beam and a wide transom, tend to develop weather helm when heeled over.

    As for the rudder, it can be improved quite a bit by simply fitting an endplate at the bottom end of it, like Phil Bolger did to many of his designs.

    In short, if you are happy with your boat, then go ahead and fit a bigger JR on it, somewhere around 40sqm (431sqft).

    Arne

    PS: I have described what I mean with a balanced hull in Chapter 2 of “The Cambered Panel Junk Rig”. This is not exactly the same as the sail balance.

     

    Last modified: 03 Jan 2016 23:12 | Anonymous member (Administrator)
  • 17 Dec 2015 16:14
    Reply # 3704161 on 3698522
    Deleted user

    Hi Arne,

    Just found your writings in the public domain portion of the site. I notice that in the docs, along with our first couple posts on this thread, you put a lot of emphasis on rudder size. Other than increasing the size of the rudder on my Compac, what else can be done to help reduce the expected weather helm on the boat? Would moving the center of effort further forward in the boat help lessen the weather helm effect?

    I don't understand the causes of weather helm specific to hull shape. So far in my somewhat limited sailing experience, I have been able to trim sails to reduce the effect. 

    I hope I am not asking a question that is answered in your online material; it is just that if I have to make major modifications to the rudder/transom of the boat, I think I should stop now before getting in too deep.

    Thanks!

  • 17 Dec 2015 15:19
    Reply # 3704023 on 3702111
    Deleted user
    Annie Hill wrote:

    I strongly recommend that you read everything that Arne has made available on this website.  It will give you much more insight into junk rig, as well as the reassurance and confidence that it's all very do-able.  I'm sure Arne wouldn't mind me saying that while he's obviously a very practical man, he's by no means a trained cabinet maker, sail maker or designer.  Indeed, his down-to-earth, hands-on approach has done a huge amount to make amateur junk rig conversions popular.

    Try working out your own sail design and then ask people here to review it.  It's winter in the northern hemisphere, so I suspect a lot of members will be happy to sail theoretically through the next few months!


    Thanks for the reply, Annie.

    I have just discovered the material that Arne made available on the site. There is a LOT of information there! I'll see about absorbing that info, and hopefully even I can make it happen. :)

    A lot of sailors north of here are down for the winter, but sailing is great here in southwest Florida this time of year. Work, sail, study will probably be my winter!

  • 16 Dec 2015 22:34
    Reply # 3702290 on 3701969
    Deleted user
    Asmat Khan wrote:

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

    *snip*

    First hoist of my home made sails, shown here, was on September 1st.

    *snip*

    I'm very happy with the rig, which I've found to be well balanced, close winded, fast and, above all, easy to handle.

    *snip*

    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.

    Ah, so only since September, not one year. I sometimes forget that most of the world uses the 'DD/MM/YYY' format (as well as the metric system) instead of the US MM/DD/YYYY that we Americans still use. We still use feet, inches, ounces, etc. as well. :)

    Thanks for the feedback!


  • 16 Dec 2015 20:28
    Reply # 3702111 on 3698522
    Mark - I have had no problems with my forward-raking mast and would always choose to go that way again.

    It took me about 50 hours to make my sail.

    The whole refit took from approximately November to April, with a lot of down time waiting for people to saw up wood, do metal work, and more down time waiting for glue to dry, epoxy to harden and paint to cure.  And of course I had to take out the old mast and put in the new.

    I strongly recommend that you read everything that Arne has made available on this website.  It will give you much more insight into junk rig, as well as the reassurance and confidence that it's all very do-able.  I'm sure Arne wouldn't mind me saying that while he's obviously a very practical man, he's by no means a trained cabinet maker, sail maker or designer.  Indeed, his down-to-earth, hands-on approach has done a huge amount to make amateur junk rig conversions popular.

    Try working out your own sail design and then ask people here to review it.  It's winter in the northern hemisphere, so I suspect a lot of members will be happy to sail theoretically through the next few months!


  • 16 Dec 2015 20:12
    Reply # 3702065 on 3701953
    Anonymous member (Administrator)
    Asmat Khan wrote:

    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). 


    I struggle with seeing why friction should be a big problem for you, since I have got away with only moderate friction. The trick is to shorten the batten parrels just enough. It also helps to use some slippery rope or webbing for batten parrels, of course, but don't worry too much about this. Too much worrying seems to be brake-pads for any projects.

    Arne

<< First  < Prev   1   2   3   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