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Aviateur 5.70 Conversion

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  • 07 Jan 2014 13:33
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    Reply # 1469288 on 1418008
    Deleted user
    Hello all and happy new year.

    I have seen the boat last month, and althought I still think it's quite a nice boat, I no longer think she would fit my needs. Or it would require too many changes. So I am closing this thread. I now consider Pioneer 21 (waiting for the study plans) or a personnal design.
  • 09 Dec 2013 10:23
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    Reply # 1454445 on 1449241
    Deleted user
    David Tyler wrote:I'd have to add a fourth rig! Now that I've got my ideas straight on how to make a soft wing-sail with UI1720 airfoil section, and with CFRP battens,  I'd like an opportunity to put them into practice. To build such a rig for Tystie is too big a project for me, but a 5.7m boat is a different proposition.
    I'm thinking of making a little rig for my dinghy this winter...
    Make it five.  Any competition without a SPLIT-JUNK rig would miss an opportunity to demonstrate what I still consider one of the most important advances in junk rig design for many years.  Still in development, but the power, simplicity, balance and lack of stress inherent in the design shows by far the most likely format to challenge the 'pointy heads'.
  • 08 Dec 2013 10:26
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    Reply # 1453923 on 1418008
    Anonymous member (Administrator)

    To swing or not to swing…

     

    I guess there are two factors playing in here:

     

    Rudders:

    Boats like Fantail, Johanna and Frøken Sørensen have very efficient rudders, which will not lose grip easily. The Aviateur 5.70 will have twin rudders, which seem to cure the steering problems associated with this sort of wide-beam boats.

     

    Chord/wll:

    Sloops have much higher chord-to-waterline ratio than two-stick rigs. Such wide sloop sails will of course be more prone to broach the boat. On my Johanna the sail’s chord is 84% of the waterline so even her quite good rudder struggles when reaching in a strong breeze. On the other hand, on my little Frøken Sørensen the chord is only 59% of the waterline, so her huge outboard rudder copes extremely well.

    Boats like Tystie and Shoestring both have quite wide sails and also moderately big rudders, so I guess it makes sense to swing their sails back and forth (or rig such boats with two smaller sails).

     

    Cheers, Arne

    Last modified: 08 Dec 2013 10:28 | Anonymous member (Administrator)
  • 08 Dec 2013 04:31
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    Reply # 1453850 on 1448918
    Anonymous member
    Arne Kverneland wrote:

    Stavanger, Sat

    Straight downwind I guess the lower AR Fantail sail might be faster, but on the other hand, it would need to be swung forward earlier to off-load the rudder. On none of my boats with Johanna style sails have I needed to do this. On both my last boats, Broremann and Frøken Sørensen, I run out of courage before I run out of rudder, so then I drop a panel or two…
    I never swing my sail on Fantail at all, but like you, Arne, I drop a panel or two when things get too exciting, or I start to get too much weather helm.
  • 02 Dec 2013 18:30
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    Reply # 1449879 on 1449597
    Deleted user

    My main concern, though, is the spaced needed by sheet system. For the moment, it seems that the bottom corner is quite close to where the sheet blocks would be (1,9m) and I am worried it could be a showstopper.

    Any thoughts ?


    You could always get round this by having the sheet in two parts with the boom and first batten sheeted separately, and then the rest of the battens sheeted together so that when the sail is reefed and therefore sitting lower you would not have such a problem with the blocks coming together. David Tyler does this on Tystie and I have been meaning to on Footprints but have never gotten to it. Another option if there proved to be a problem would be a small boomkin type frame out on the stern of the boat for the sheet attachment. On Footprints I cannot pull the sheet tight when the sail is lowered so I wrap the sheetlets a couple of times around the end of a protruding batten end.
     
    Last modified: 02 Dec 2013 23:13 | Deleted user
  • 02 Dec 2013 10:45
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    Reply # 1449602 on 1418008
    Anonymous member (Administrator)

    Antoine, I would not be too worried about that lack of room for the sheets. None of my boats has had sufficient space to fully sheet in the furled sail bundle, the way Practical Junk Rig describes it.  Still, as long as I can sheet in the deeply reefed sail for close-hauled sailing, I am happy enough. I secure the furled sail bundle with strings to each side. But then all my boats have been sloops with the sail and sheet bundle easily within reach from the cockpit  -  just as your boat will be.

    Arne
  • 02 Dec 2013 10:22
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    Reply # 1449597 on 1418008
    Deleted user
    Hi all, I can see the ball is rolling !

    The drawing are quickly done. I still have to work on them. For example, i still need to work on relative position of CLR and CE for both the rigs (if you have any idea on that ...) and weight. Than, I will send them to Eric Henseval for him to have a look.

    My main concern, though, is the spaced needed by sheet system. For the moment, it seems that the bottom corner is quite close to where the sheet blocks would be (1,9m) and I am worried it could be a showstopper.

    Any thoughts ?

    Antoine
  • 02 Dec 2013 06:54
    Quote
    Reply # 1449541 on 1449241
    Deleted user
    David Tyler wrote:I'd have to add a fourth rig! Now that I've got my ideas straight on how to make a soft wing-sail with UI1720 airfoil section, and with CFRP battens,  I'd like an opportunity to put them into practice. To build such a rig for Tystie is too big a project for me, but a 5.7m boat is a different proposition.
    I'm thinking of making a little rig for my dinghy this winter...


    This is going to be bigger than the Americas Cup - a 4 boat sail off with cutting edge rig design!!!

    Actually I think the soft wing sail would be a very interesting rig to put on one of these boats. I had been wondering David whether your mizzen sail off Tystie would be adaptable to one of these boats although maybe the foil section would be all wrong. It would be interesting to see a soft wing sail rig design to suit Aviateur.

    Last modified: 02 Dec 2013 06:55 | Deleted user
  • 01 Dec 2013 19:56
    Quote
    Reply # 1449241 on 1418008
    Anonymous member
    I'd have to add a fourth rig! Now that I've got my ideas straight on how to make a soft wing-sail with UI1720 airfoil section, and with CFRP battens,  I'd like an opportunity to put them into practice. To build such a rig for Tystie is too big a project for me, but a 5.7m boat is a different proposition.
    I'm thinking of making a little rig for my dinghy this winter...
  • 01 Dec 2013 05:04
    Quote
    Reply # 1449036 on 1448918
    Deleted user

    David Thatcher compares his cambered Fantail sail with his former, flat, HM sail and from that experience, he seems to rule out the HM sail. I think that is a bit unfair comparison. When I replaced my Malena’s flat HM sail with a cambered panel HM sail of the same size and AR, it was like having a turbocharger added. That was back in 1994  -  it’s only 6 months now to the 20-years anniversary of that blue, cambered panel sail.

    So my suggestion, again, is that both sails you have drawn will do fine, and that they will anyway work a lot better than a flat sail. It is more up to you what you like.

    Good luck!

    Cheers Arne

    PS: Btw, the default rake of my masts is vertical, but these sails have proven (to me) that they work with any mast rake from 2 degrees aft to  over 5 degrees forward.


    Sorry, I wasn't at all ruling out the HM patterned sail. In fact there were times during my recent 2 ocean crossings on Footprints when I wished for a taller rig with shorter battens and hence a shorter sail bundle, which might have been easier to manage in some of the very rolly ocean conditions we had. As it is there is not much diference in the length of battens and mast heights between the two rigs that Antoine has drawn ...... but my gut feeling is that the fantail rig might be a bit more of a powerhouse down wind, and I prefer the look of the fan shaped sail and it's square top. If I do get to build one of these boats it will be the route I will go down. I have spent 18 months getting to know the fan shaped sail and learning how to make it work and I think it would be fun to try a smaller version of the rig.

    It would indeed be an interesting expgeriment to try this design with the 3 different rigs; the bermudan, the HM pattern junk sail, and the fan shaped junk sail and to be able to sail them side by side. We could have a best of 3 challenge race!

    Last modified: 01 Dec 2013 05:07 | Deleted user
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