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Getting the best from your sail

  • 05 Aug 2014 09:46
    Quote
    Reply # 3063839 on 3063828
    Anonymous member
    Arne Kverneland wrote:

    Paul,

    It will be interesting to hear about the change in handling you notice with the new rudder.  Standard rudders, sitting right aft of a long keel work in a much slowed-down waterflow, caused by the boundary layer, so fancy sections make no sense here. Now that you move the new rudder aft and away from the hull, hopefully the waterflow has had time to speed up again before it hits the rudder.

    Good luck!

    Arne

    Arne, I will be reporting back. I'm making the changes that I am after consulting with several well known names in the yacht design business. So presumably I should not be too far off.
  • 05 Aug 2014 08:40
    Quote
    Reply # 3063828 on 3056306
    Anonymous member (Administrator)

    Paul,

    It will be interesting to hear about the change in handling you notice with the new rudder.  Standard rudders, sitting right aft of a long keel work in a much slowed-down waterflow, caused by the boundary layer, so fancy sections make no sense here. Now that you move the new rudder aft and away from the hull, hopefully the waterflow has had time to speed up again before it hits the rudder.

    Good luck!

    Arne

     
  • 05 Aug 2014 01:53
    Quote
    Reply # 3063684 on 3062936
    Anonymous member
    David Thatcher wrote:

    On the subject of balance, and this may lead to a new thread, I am about to build a new rudder for Footprints. Insurance repairs are underway on Footprints following damage during a recent mooring incident. When the boat builders started repairs on the rudder they found the whole of the rudder stock to be rotten. While I could patch up the old rudder it is actually easier to build a new one. I was not at all upset by this as I had been thinking a lot about the performance of the rudder in recent months as I know good rudder design can do a lot for the performance of a yacht, and I have been wanting to lighten the tiller loads on Footprints. I am about to start gluing up the timber for the rudder so am now looking to get the best foil shape possible and also add more balance area to the rudder. I am interested to hear of anyone's experience in this area. 

    David, I'm in the process of building a new rudder for LC right now. I'm using a NASA0015 profile with 20% balance on a simple 2.7 aspect rectangular shape. The ruder is supported at the bottom so it's not a spade. It also has two small end plates. The rudder hangs vertically from the stern instead of at a 35deg angle that the old one did. No photos yet as I'm still waiting on the laser cutting to be completed before I can start building. One thing that is important. If you are going to all the trouble of building a new rudder, you need to make it as accurately as possible so as to gain as much benefit as you can from all your hard work.
  • 04 Aug 2014 21:24
    Quote
    Reply # 3063540 on 3063227
    Anonymous member (Administrator)
    Ketil Greve wrote:

    David,

    I changed the rudder of Edmond Dantes to a slimmer deeper design from jefa.com in Denmark. The transformation was unbelieveable. I have a plan for changing the rudder of Marie G too.

    Ketil. 


    I can second Ketil’s saying. The new rudder of Edmond Dantes is almost too good. Not only is it very powerful, even at low angles, but it is also so well balanced that ED can be hand-steered  for hours, even on a roaring broad reach  -  which I have done. In fact there is the danger of not sensing the rising wind from behind and end up bending or breaking something in the rig. Last summer this happened to the owner, Håvard: He reported that he was doing «between 6 and 8 knots». It is just that it takes A LOT of brute force to even approach 8kts in ED  -  so in the evening he reported that batten 2 (from top)  -  the one which is twice as strong as the others  -  had bent.

    The thing is that the Chinese had/have a very different view on what the rudder is made for. Their centre-boards are usually positioned well forward of the wanted position of the CLR. The rudder then work as centre-board number two  -  in addition to steering the boat. The Chinese would never run out of rudder and I cannot see any signs that they used to shift their mainsails either (Hong Kong schooners ).

    I am not against shifting the junk sail back and forth, but I guess I regard it as a plan B. If I can choose, I will rather go for a boat with a powerful rudder. Several of us do fine without needing to shift their lo-AR sloop sails; Edmond Dantes, Johanna, Frøken Sørensen and Fantail, among (hopefully) others. For those of you who have boats with a shallow, inferior rudder, I recommend that you add a generous endplate to it. That is a quick-fix that really works.

    Cheers,
     Arne

    Last modified: 07 Aug 2014 10:20 | Anonymous member (Administrator)
  • 04 Aug 2014 15:31
    Quote
    Reply # 3063227 on 3056306
    Anonymous member

    David,

    I changed the rudder of Edmond Dantes to a slimmer deeper design from jefa.com in Denmark. The transformation was unbelieveable. I have a plan for changing the rudder of Marie G too.

    Ketil. 
  • 04 Aug 2014 11:27
    Quote
    Reply # 3063019 on 3056306
    Anonymous member

    I have an aft and a fore tack line, I think the only way I could can't the sail would be to ease the luff hauling parrel.
  • 04 Aug 2014 06:37
    Quote
    Reply # 3062936 on 3062680
    Deleted user
    Robin Fröberg wrote:

    In my opinion it's very useful to be able to move the sail forward and back to achieve good balance on all courses in all wind speeds so with Vanharouva's new sail i didn't fit a mast lift or a tack line but one line  from the after part of the boom to block on the mast foot and one from the fore end of the boom also to the mast foot and to the cockpit where it is easy to move the boom fore and aft. Imagine going to windward with the the sheets hanging loose and the sail balancing perfectly....of course I usually use a little weather helm but it's a joy to play.....

    Robin Fröberg


    Like Robin's boat the sail on Footprints has the ability to be canted across the mast. I think for a low AR sloop junk rig this has the advantage in being able to minimise weather helm and obtain better balance with the boat. Canting the sail does require extra control lines and is a bit more work when sailing compared to a 'don't touch anything' junk sail, but I always think that the sailors of conventional rig boats are still doing a lot more work with all their control lines and having to constantly handle jib sheets. . Actually canting the sail requires almost no effort as the sail is hanging from the yard anyway so will fall either forwards by itself and can be pulled back again very easily.

    On the subject of balance, and this may lead to a new thread, I am about to build a new rudder for Footprints. Insurance repairs are underway on Footprints following damage during a recent mooring incident. When the boat builders started repairs on the rudder they found the whole of the rudder stock to be rotten. While I could patch up the old rudder it is actually easier to build a new one. I was not at all upset by this as I had been thinking a lot about the performance of the rudder in recent months as I know good rudder design can do a lot for the performance of a yacht, and I have been wanting to lighten the tiller loads on Footprints. I am about to start gluing up the timber for the rudder so am now looking to get the best foil shape possible and also add more balance area to the rudder. I am interested to hear of anyone's experience in this area. 

    Last modified: 04 Aug 2014 06:38 | Deleted user
  • 03 Aug 2014 22:19
    Quote
    Reply # 3062777 on 3062646
    Anonymous member
    Arne Kverneland wrote:
    Gary Pick wrote:

    Just curious as PJR deals with flat panel sails, are gybes softer with flat panels?


    Gary,
    I never noticed any difference between gybing flat and cambered sails on my Malena, athough I guess I get an earlier warning with cambered panels.

    Arne


    Thanks Arne, I was thinking maybe the camber might add extra windage on the way across, guess not. I plan to put an arch over the cockpit.
  • 03 Aug 2014 16:54
    Quote
    Reply # 3062680 on 3056306
    Deleted user

    In my opinion it's very useful to be able to move the sail forward and back to achieve good balance on all courses in all wind speeds so with Vanharouva's new sail i didn't fit a mast lift or a tack line but one line  from the after part of the boom to block on the mast foot and one from the fore end of the boom also to the mast foot and to the cockpit where it is easy to move the boom fore and aft. Imagine going to windward with the the sheets hanging loose and the sail balancing perfectly....of course I usually use a little weather helm but it's a joy to play.....

    Robin Fröberg
  • 03 Aug 2014 15:49
    Quote
    Reply # 3062665 on 3056306
    Anonymous member

    I've been pleasantly surprised at how much easier a high aspect ratio rig is to handle. Coming up the Juan de Fuca Strait in a rising wind that was swinging from W to NW, I long-gybed multiple times without problems, when I would have been somewhat nervous under my Fantail sail.

    I agree that cockpit hoops are highly desirable on most boats, and essential with a big rig where personal injury would result from being caught by the sheet. Also, I like the way that the square of canvas that I've rigged between my two hoops keeps the sheet blocks off my head when I tack, and when I drop the sail head to wind.
       " ...there is nothing - absolutely nothing - half so much worth doing as simply messing about in junk-rigged boats" 
                                                               - the Chinese Water Rat

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