Suitability of a large sloop rig for cruising

  • 27 Nov 2025 04:07
    Reply # 13567388 on 13567371
    Anonymous member (Administrator)

    Thomas wrote:

    Thank you Arne and David for the insight.

    I was looking at Le Forestier's designs and the 10.5m has large 50sqm single masted rig. The idea of a running tack parrel seems like it would make sense, and the extra control line wouldn't be an issue with the one sail. That and the forward raked mast to get the CG further forward seems like it would help. 

    Is a cambered sail possible with a forward raked mast? 


    Thomas

    Yes, camber will work.


    Arne

    Last modified: 27 Nov 2025 11:03 | Anonymous member (Administrator)
  • 27 Nov 2025 02:01
    Reply # 13567371 on 13567068

    Thank you Arne and David for the insight. 

    I was looking at Le Forestier's designs and the 10.5m has a large 50sqm single masted rig. The idea of a running tack parrel seems like it would make sense, and the extra control line wouldn't be an issue with the one sail. That and the forward raked mast to get the CG further forward seems like it would help. 

    Is a cambered sail possible with a forward raked mast? 


  • 26 Nov 2025 19:45
    Reply # 13567298 on 13567068
    Anonymous member (Administrator)

    The two sailplans below illustrate the development of the Johanna-style JR.  By lowering the yard angle from 70 to 60 and thus allowing for increasing the mast balance from max 17 to max. 27%, the distance from the CE to the mast  -  and thus to the CL, when running before, will be much reduced. One may even tilt the sail forward until the mast balance at the boom reaches 30 %. This will both give easy steering downwind, and reduce the chances that the sheetlets will catch any protruding boom there.

    Look up Paul Schnabel’s Ylva and see for yourself.

    As for handling the sail, sheeting forces become lighter the more mast balance there is, For hoisting the big sail, I recommend an electric capstan, with a manual one as backup. The consumtion of Amp-hours is tiny compared to a day’s use of auto pilot.

    An efficient and well-balanced rudder will anyway be a good thing.

    Cheers, Arne


    (..Full size diagram on Arne’s sketches, section 8… )


    Last modified: 26 Nov 2025 19:57 | Anonymous member (Administrator)
  • 26 Nov 2025 09:27
    Reply # 13567104 on 13567068

    My experience with Tystie, 34ft 6in and about 8 tons, is relevant here, as I interrogated this very question over many miles of ocean and coastal cruising between 2000 and 2015, with a variety of single sails and ketch rigs (but not with a schooner rig nor with a SJR, as these would have been incompatible with the layout of the accommodation). A look back through the forums and magazines over this time period should fill in the detail, but the bottom line is yes, a single sail is feasible, but a sail with low AR means that helm balance can be problematic unless it can be moved across the mast for downwind work. This needs more running luff parrels, so gets a bit more complicated to use when negotiating narrow winding channels, for example. Also, the battens and yard, being longer, need to be stiffer, stronger, and therefore heavier, so that the total weight of the sail bundle is greater for a low AR sail than for a high AR sail of the same area. So I came to the view that a high AR sail was the way to go for large single sails. The physical effort of hoisting and sheeting a large sail is not too much of a problem, given good winches and blocks, and a single handed sailor with a reasonably good level of fitness and strength should be able to manage up to 600 sq ft. I wouldn't want to go larger than this, though.

    Sadly, I never got to try a SJR of this size on Tystie, but my hunch is that this would be the optimal way to go for ease of management of a large sail, while also providing good performance, so long as the mast didn't have to be placed in an inconvenient position relative to the accommodation, as was the case with Tystie. If your plan is to first decide your preference for type of rig, then to choose a suitable existing boat to convert, or better still to build accommodation into a bare hull to suit the preferred rig, then this isn't a problem.

  • 26 Nov 2025 03:59
    Message # 13567068

    How feasible is it to convert a 30-35ft boat somewhere around 6-9 tons displacement and rig it as a sloop? Would a rig of 600-700sqft require too much steering force for windvane self steering? I understand a ketch or schooner rig would be preferable,  but the simplicity of a single sail is appealing. 


    The only example I've found is Paragrine, and I'm unsure is she is used for long range cruising much.