Wingsail or Junk?

<< First  < Prev   1   2   3   Next >  Last >> 
  • 19 Jan 2020 10:31
    Reply # 8618566 on 8618310
    Randy wrote:

    As I mentioned in another reply, the bowsprit is to me, a beneficial device, if just for the pure joy! :) I also have a mizzen sail, main sail and two foresails, but all undersized. I imagine the foresails will work fine, but I'd likely take the Main and Mizzen I have and make one junk Mizzen, leaving me having to only make one large main from scratch.

    For the Mizzen, I imagine I need the four shrouds, though, as you mention. Wouldn't I? I Could make this sail a wingsail, but actually, I think I'd i'm leaning to make both as junk sails. The challenge I have here on the mizzen is that it will hang over the stern, requiring something of a stern sprit?

    If all goes well, I hope to make it to Brest for the big festival! And ideally the AGM in Brixham.

    So I think you end up with something like the sail plan that Arne sketched for you. One or two headsails, staysail to the stemhead and flying jib on a furler to the bowsprit end, with two shrouds and forestay to support them. As big a junk main as will fit, with a high-peaked yard to clear the forestay. A small junk mizzen on a mast with four shrouds, and double sheeting, port and starboard, to make it useable as a riding sail and to avoid having a spar extending the LOA.

    On sailcloth: 11oz Top Gun is favourite for this size of boat, but be aware that making large sails out of heavy cloth is a challenge. I've made a number of large sails from 9oz cloth and would be terrified at the though of making one from 11oz cloth. It would need a very large floor and sewing table, and at least two helpers to move the weight and bulk of the near-complete sail around while the machinist moves only that part of the cloth that is near the machine.

    there's a way around this. The way that Roger Taylor devised for the sail on Mingming II, with the sail in sections, joined at the batten with alternating pocket sections on each panel, with the batten passing through them, so that it looks like a metal hinge when assembled. It would be much less daunting to make a large sail this way. I worked with Paul to make Aphrodite's sails out of 11oz Top Gun in separate panels, joined by the battens, but I'd be happy enough to make a large sail in three or four sections of two or three panels each. Anyway, make the mizzen first, to get experience in passing heavy cloth through the machine without too much total weight to manage. Another point is to think carefully about the number of layers that are to pass under the needle at once, and keep it down to three. That's easy enough to arrange along the batten pockets, luff and leech, but it's where three layers at luff and leech meet three layers at batten pockets at the corners of the panels that even the strongest machine will struggle, where you get as many as six layers of heavy cloth.

  • 19 Jan 2020 09:49
    Reply # 8618310 on 8599026
    So it's back to putting in the time and effort to make a big flat junk sail with plenty of balance. Flat, because this is never going to be a boat that will go to windward in light breezes, and a flat sail will work fine when the wind pipes up. Plenty of balance, and a low yard angle, to keep the loadings low, and I hope to obviate the need for a headsail.

    The mizzen will be small, with little balance area, and often furled in fresh breezes for better helm balance. It could be a Wharram wing, to save on time and effort in making it, or it could be a junk sail, to make it more useful as a riding sail.

    Whatever the sails, I'd be thinking of four shrouds, two forward and two aft, rather than two after shrouds and a headstay (to avoid having a bowsprit).

    As I mentioned in another reply, the bowsprit is to me, a beneficial device, if just for the pure joy! :) I also have a mizzen sail, main sail and two foresails, but all undersized. I imagine the foresails will work fine, but I'd likely take the Main and Mizzen I have and make one junk Mizzen, leaving me having to only make one large main from scratch.

    For the Mizzen, I imagine I need the four shrouds, though, as you mention. Wouldn't I? I Could make this sail a wingsail, but actually, I think I'd i'm leaning to make both as junk sails. The challenge I have here on the mizzen is that it will hang over the stern, requiring something of a stern sprit?

    If all goes well, I hope to make it to Brest for the big festival! And ideally the AGM in Brixam.

  • 18 Jan 2020 19:47
    Reply # 8612914 on 8568472
    Anonymous member (Administrator)

    Randy

    The hounds limits the size (height) of the junk sail just as it does with a gaff sail. If you move the hounds upwards, I can move the yard upwards as well, and maybe even make the battens a bit longer. I would not make the sail much wider, though, since a generous clearance for the main sheet is good to have, in particular on a sail over 40sqm.  However, if moving the hounds calls for a major surgery of the mast, I suggest you leave it as it is. After all, your vessel started as a motor trawler. These are not particularly fine-lined and easily driven, so in many cases you will be motor-sailing, using both sail and engine (one lower rpm), but still burning less fuel than before.

    Flat or cambered sail.
    When I wanted to upgrade my first flat junksail to camber, back in 1990, my motive was solely to improve speed to windward. I surely got that, but I also found the cambered sail to be much more powerful on all angles between broad reach and close-hauled. This is where your sail will give the biggest help ( the two 90° wide zones between 60° and 150° from the true wind). On these legs, a JR with a really good camber (10%?) will almost double the drive compared to a flat junk sail.

    Sailcloth
    I know some are using the stout 12oz.(?) Topgun canvas, for demanding tasks, and are happy with it.

    Arne


    Last modified: 19 Jan 2020 11:10 | Anonymous member (Administrator)
  • 18 Jan 2020 18:25
    Reply # 8612403 on 8609861
    Anonymous wrote:

    Bigger sail?

    There are two limitations here:
    Number one is the existing mast and the position of the hounds.

    The other is, as you point out, the position of the COE. The Chinese vessel you show us gets away with the aft-set rig by having a huge rudder, which actually acts as an aft centreboard.

    The rudder of you motor vessel  is probably not very big, and unless the propeller is working, will have little authority. To improve it, I recommend adding a big endplate onto its lower end.

    Arne


    Yes, I do plan to enlarge my rudder.

    So, what will the position of the hounds mean to enlarging the sail? I guess I'd like to get as big as possible, thinking in my mind that will improve her ability? But, I'll take the advise from you pros .

    What is the recommended for sail cloth? I am the proud owner of a walking foot sewing machine, so in theory, I should have sail making potential.  

  • 18 Jan 2020 18:19
    Reply # 8612368 on 8609665
    Anonymous wrote:

    Randy,

    yes, to quote Tom Cunliffe in his book ‘Hand, reef and steer’:

    “Hounds: The part of the mast which the main
    shrouds are attached. In a gaffer it is well up the
    shaft, because it must be above the gaff-jaws.”

    Funny about the images. They are meant to be opened (after some delay) if you click on them.
    Maybe this link to my member’s photo album will work better for you.

    Cheers,
    Arne


    I never even considered opening the image! LOL I can see them fine when I do that. Go figure  


    Hounds... got it.

  • 18 Jan 2020 11:35
    Reply # 8609861 on 8568472
    Anonymous member (Administrator)

    Bigger sail?

    There are two limitations here:
    Number one is the existing mast and the position of the hounds.

    The other is, as you point out, the position of the COE. The Chinese vessel you show us gets away with the aft-set rig by having a huge rudder, which actually acts as an aft centreboard.

    The rudder of you motor vessel  is probably not very big, and unless the propeller is working, will have little authority. To improve it, I recommend adding a big endplate onto its lower end.

    Arne


  • 18 Jan 2020 11:01
    Reply # 8609665 on 8568472
    Anonymous member (Administrator)

    Randy,

    yes, to quote Tom Cunliffe in his book ‘Hand, reef and steer’:

    “Hounds: The part of the mast which the main
    shrouds are attached. In a gaffer it is well up the
    shaft, because it must be above the gaff-jaws.”

    Funny about the images. They are meant to be opened (after some delay) if you click on them.
    Maybe this link to my member’s photo album will work better for you.

    Cheers,
    Arne


  • 18 Jan 2020 10:01
    Reply # 8609291 on 8601873
    Anonymous wrote:

    The problem is, I don’t know the distance up from deck level to the hounds. Only when I know this (plus the accurate mast position), can I draw a more accurate rig. Here I have just guessed the hounds to sit 11.5m above deck and then I moved the forestay and main halyard up another half metre. As you see, I have also fitted a staysail  -  too bad not to make use of that stay. For the mizzen I just copied Alan Boswell’s sail.

    Actually, unless you know that you need the mizzen to avoid sailing around at anchor, I would wait with it, as I doubt if the mainsail plus staysail alone will cause a noticeable lee helm.

    What are the hounds? Is that the point where the stays/shrouds connect to the mast? 


    I almost put up just a mizzen last summer for stability while under motor or at anchor. Both of which I feel would be worth the effort. 

    unfortunately the images you uploaded are too low quality to read the words you superimposed over the image  could you reupload in pdf or larger image? PDF will be much clearer. 


  • 18 Jan 2020 09:57
    Reply # 8609272 on 8568472

    Boy, you guys rock! Great thoughts. 

    I would actually like to have a bowsprit, even if it’s just to support a net to lay in while viewing the surfing dolphins. I dare say it’ll be the favourite hang out for our kids!

    id be keen, I think, to do the junk sail on that main mast for ease of handling. And to feel I’ve accomplished a long held dream. Can it be bigger, that sail? Wouldn’t that produce more moving power? Some of the old images of large junks I see seem to have MUCH deeper sails. Longer parrels/boom. Could not go right back to the aft of the pilot house? Or is that putting the COE to far aft?

    thinking of the image I have here:

    1 file
  • 17 Jan 2020 15:40
    Reply # 8601873 on 8568472
    Anonymous member (Administrator)

    Randy,

    just for fun, I had a little go to sketch up an AUX rig for your vessel. I fitted the mainmast 1/3 of the boatlength aft of the bow and then just dropped one of my master sails on it. The problem is, I don’t know the distance up from deck level to the hounds. Only when I know this (plus the accurate mast position), can I draw a more accurate rig. Here I have just guessed the hounds to sit 11.5m above deck and then I moved the forestay and main halyard up another half metre. As you see, I have also fitted a staysail  -  too bad not to make use of that stay. For the mizzen I just copied Alan Boswell’s sail.
    Actually, unless you know that you need the mizzen to avoid sailing around at anchor, I would wait with it, as I doubt if the mainsail plus staysail alone will cause a noticeable lee helm.

    Anyway, since the rig is rather small (even with the hounds a metre higher up), I strongly recommend that you give the mainsail plenty of camber. Don’t let anyone tell you that making a cambered panel sail is difficult! There is actually the advantage that you loft each batten panel one by one, which lets you get away with a lot smaller  lofting floor.

    Cheers,
    Arne



    Last modified: 18 Jan 2020 11:23 | Anonymous member (Administrator)
<< 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