Converting Vagabond 47 to Junk Rig

<< First  < Prev   1   2   Next >  Last >> 
  • 03 Feb 2024 11:25
    Reply # 13310048 on 13310030
    Anonymous wrote:

    With the given diagram are hybrid type rigs viable?

    There certainly have been hybrid rigs - look at Bertie, for example. One issue is that you would need standing rigging, with all the expense and maintenance that that entails. Also, the shrouds would probably prevent you from being able to fully square out the sails for downwind sailing, and, in such a situation, it's very likely that there'd be an issue with chafe with the sails rubbing against the shrouds.
    I have to say, that in my humble opinion, the sails suggested by John aren't actually junk sails - they have no balanced portion forward of the mast. I also suspect that the advantage of easy reefing would be diminished by having the forward end of the sail running in a track - I can't imagine the sail dropping easily when filled with wind, which a conventional junk sail will do without issue.
    I admit that the idea of rigid battens running on batcars is a new idea, should be carefully tested, though batcars runs down smoothly for flexible full battens. Some traditional Chinese junks do have little balanced portion forward of the mast (see Swatow Junk image). Proper junk rig do drop very smoothly. Its not necessary to sail headwind before reefing,  the sail can come down smoothly even filled with wind.
    1 file
  • 03 Feb 2024 09:13
    Reply # 13310030 on 13309214

    With the given diagram are hybrid type rigs viable?

    There certainly have been hybrid rigs - look at Bertie, for example. One issue is that you would need standing rigging, with all the expense and maintenance that that entails. Also, the shrouds would probably prevent you from being able to fully square out the sails for downwind sailing, and, in such a situation, it's very likely that there'd be an issue with chafe with the sails rubbing against the shrouds.
    I have to say, that in my humble opinion, the sails suggested by John aren't actually junk sails - they have no balanced portion forward of the mast. I also suspect that the advantage of easy reefing would be diminished by having the forward end of the sail running in a track - I can't imagine the sail dropping easily when filled with wind, which a conventional junk sail will do without issue.
  • 02 Feb 2024 10:34
    Reply # 13309549 on 13308065

    As the CE of the junk and mizzen sails are more or less in their original position, the two fore sails should work perfectly with the cambered junk sails. So far if you sew in a boltrope along the leech which is fixed to the rigid battens to form a ladder structure, the tension on the sail fabric is much lighter than the bermudan sail. As the tension on the sail is distributed to the ladder structure rather than concentrated on the 3 corners. This answers why junk sails can sail in shredded sail (see picture) while Bermudan sails cannot. This ensure that you can always sail home safely. Another interesting difference is that junkrig does not need a boom vang. Traditional junk sails were simply hung from the halyard with gravity. You can use a system 2 main sheets, one from each side of the boat (note: pulling the sail sideways from upwind side and not from aft). You will find that the sheet is much lighter than Bermudan rig. This is another safety feature.

    2 files
  • 01 Feb 2024 19:50
    Reply # 13309214 on 13308895
    Anonymous wrote:

    The major advantages of junk rigs are: 1.quick and easy reefing, 2.light gybing due to CE close to mast (pivot). As gybing under strong wind can be safely done with "chicken gybe" (270 degree turn), you can consider a junk rig sail for quick and easy reefing only. A full rigid batten cambered sail and lazy jacks typical of junk rig which have the same area as the original triangular sail. The rigid battens slide on the mast track with batcar. (see sketch attached). As the fore sails can reef easily with furler, there is no need to turn them into junk rig.

    With the given diagram are hybrid type rigs viable? I like the idea of keeping the masts in the same location, so would the staysail and yankee still work in conjunction with a junk main and a smaller junk mizzen? 

    Also unrelated to the specific rig, are there any major differences in upkeep/maintenance between junk rigs and bermudian rigs? 

    1 file
  • 01 Feb 2024 10:18
    Reply # 13308895 on 13308065

    The major advantages of junk rigs are: 1.quick and easy reefing, 2.light gybing due to CE close to mast (pivot). As gybing under strong wind can be safely done with "chicken gybe" (270 degree turn), you can consider a junk rig sail for quick and easy reefing only. A full rigid batten cambered sail and lazy jacks typical of junk rig which have the same area as the original triangular sail. The rigid battens slide on the mast track with batcar. (see sketch attached). As the fore sails can reef easily with furler, there is no need to turn them into junk rig.

    1 file
  • 01 Feb 2024 09:53
    Reply # 13308891 on 13308065
    Anonymous member (Administrator)

    It is easy to fall in love with the schooner rig, whether it is gaff or junk. This has resulted in some schooners with a constant weather helm, because the builder has not fully counted with the effect of having a long keel and a smallish rudder at the end of it. This weather helm may be accepted or at least tolerated as a part of the concept.

    On the Stavanger-schooner Samson (soon to move to Poland) the owner fitted hydraulic steering, which makes handling tolerable. Still, I think he would have been better as a ketch(..but not as good-looking...). Problem was that when I was asked to design a JR for Samson, the vessel was almost finished, so I had to fit the masts as shown.

    Samson sails pretty well, though; he is quite fast and close-winded, and easy enough to handle for coastal cruising. How he behaves in a mid-Atlantic gale, remains to be seen. I know that Svein, the builder, just set the foresail when going downwind in a blow, and that worked well for them.

    Arne


    Samson in 2011

    ( full size photo in my photo album no. 8)

    Last modified: 01 Feb 2024 09:56 | Anonymous member (Administrator)
  • 31 Jan 2024 19:23
    Reply # 13308593 on 13308199
    Anonymous wrote:

    Yeah that’s a really good point. I like the idea of utilizing the same mast positions and adding an additional mast for a smaller sail near the bow. So overall having 3 sails. Do you think a smaller

    (smile) Yeah, we all _like_ the idea of using the stock mast positions. However, generally reality sets in shortly after that  :P    As David T. has just pointed out, the main reason (with any rig really) of splitting sails is weight and handling. While there are racing boats with huge sails, they also come with huge crews (the first boat across the finish in Sydney/Hobart had 21 crew). Thus the suggestion of max sail size of 500sqft/50sqM.

    one similar to a mizzen mast in the aft, with a large midship sail, and a small forward sail is a reasonable sail plan? What all is required to have a sail near the bow?

    The same as putting a keel stepped mast anywhere ;)  The only extra thing to worry about is leaving at least 3 feet/1M between the sails when they are held amidships to give room for the sheets and that is still pretty tight.

    For reference I saw a photo that I have attached as a visual of what inspired me to think that it could be done with my boat. What type of sailing configuration is in the photo? 

    I think we would call that fully rigged? What it is called is less important than if it is a good fit for you. The cost is three times the cost of one mast, where cost includes money and time and sail handling after you set sail as well.

    from my sailing experience with the boat I really only used 2-3 sails at a time with majority being the mainsail, mizzen, and the yankee. 

    Assuming that gives you the best balance (least helm input) on a beam reach, you might calculate your over all centre of area based on those three sails. If the balance is not quite right think about moving you centre of area fore or aft a bit to make it better.

    Now take the line drawing you have and expand it to some amount that allows a drafting scale to be used for direct measurements. The ones I have are all 12 inches long triangular extrusions with various scales from 1inch = 1 foot down to 1/8 inch = 1 foot.... buy the scale first so you know what scales you have to work with. I am sure there are metric versions available too but I bought mine in the late 70s when I was taking drafting in school. I would aim for a drawing bigger than will fit on a letter size paper but I have personally used letter paper too  ;)

    Anyway, Once you have such a drawing, you can either cut out various size sail shapes and move them around to make the centre of area match the original or draw these shapes on the drawing. For first steps I would just use rectangles where the centre of area for each sail is half way back from the luff (the real JR sails are very close to this anyway). You want a maximum area of 500^2ft/50^2M for any one sail for one person to be able to deal with it with no winches (though there are a number of people who use a winch for the last few panels even then)

    Once you have these sails arranged on the drawing for the right balance, you can see that mast placement should be between 5% to 20% aft of the luff, assuming Arne style sails. Speaking of which, Arne's write up probably explains this a whole lot better than I am.

    Anyway, If the first time does not allow good mast placement, you can move sails fore and aft by changing their size to compensate. Personally, I would suggest that David T. has already done these steps in his post. He has chosen to make both sails the same size to give the most sail area with only two masts.... Most of us aim for least masts ;)

    Do look at Arne's files

    In particular his "book" which explains things really well.

  • 31 Jan 2024 13:15
    Reply # 13308309 on 13308065

    There have been successful boats at around this size and displacement with two equal sails of around 500 sq ft - Ti Gitu comes to mind, and it would be worth contacting Paul to discuss his experiences, or at least read his articles in the JRA magazine.

    My own relevant experience was with a smaller boat, sometimes a ketch, sometimes a sloop, but always with a mainsail in the range 500 - 600 sq ft. This is a reasonable size to handle. There have been bigger sails (eg on Peregrine), but I think that 600 sq ft is a sensible top limit. If you were to go for three masts, then the three sails, especially if they are of different sizes with a mainsail larger than 600 sq ft, get rather more complicated to design, build, and sail with, so my feeling is that it makes sense to stick with two equal sails if at all possible.

    Looking at sailboatdata, and assuming that the deck and accommodation are as described there, it would appear that the foremast would come down somewhere near the forehatch/V berth area, and the after mast somewhere near the forward end of the saloon. These positions seem to me to be practical and possible.

  • 31 Jan 2024 03:11
    Reply # 13308199 on 13308065

    Yeah that’s a really good point. I like the idea of utilizing the same mast positions and adding an additional mast for a smaller sail near the bow. So overall having 3 sails. Do you think a smaller one similar to a mizzen mast in the aft, with a large midship sail, and a small forward sail is a reasonable sail plan? What all is required to have a sail near the bow? 

    For reference I saw a photo that I have attached as a visual of what inspired me to think that it could be done with my boat. What type of sailing configuration is in the photo? 

    from my sailing experience with the boat I really only used 2-3 sails at a time with majority being the mainsail, mizzen, and the yankee. 

    1 file
  • 31 Jan 2024 00:24
    Reply # 13308157 on 13308065
    Anonymous wrote:

    Hello,

    I currently own a Vagabond 47 https://sailboatdata.com/sailboat/vagabond-47/ , and my ambitions with it are to continue voyaging across oceans and along coasts. 


    hmm, lots of sail area. Currently it is divided into 4 sails. Considering that you are planning to replace them with only 2 and each of those with battens, I would think evening out the sail area between the two masts would make sense. That is, increase the sail area on the mizzen and decrease it on the fore. However, this would mean moving your masts forward. Assuming the centre of area will remain at the same place (fore and aft, junk rigs tend to move the CA up a bit), you need to think about how much you are willing to  affect your interior layout. Would putting the foremast at the aft of the chain locker/front of the v-berth put too much weight too far forward? Do you mind if there is a mast in the middle of the v-berth (this looks like a good place for it from a "we don't care about the interior" POV)? Would three masts work better? (the main could stay pretty close to where it is now)

    Would the fore deck look out of place? does it matter? Remember that junk rigs (except Colvin's Doxy and Gazelle maybe others) do not usually include fore/stay sails and therefore no bow sprite.

    Anyway sounds like a great project.

<< 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