Conversion project - Trismus 37

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  • 29 Nov 2020 20:27
    Reply # 9393400 on 9390257

    Hi Andre,

    the CLR is normally calculated without the rudder, this means it will be a little further forward than shown on your sail plan #2. I find that a lead of about 12% is generally about right for a split rig, although on Arcadian it was not enough and I increased it on her to about 17% in order to balance the helm.

    All the best with the project, David.

  • 29 Nov 2020 16:40
    Reply # 9393101 on 9390257
    Anonymous

    Hello,


    Thanks for the suggestions.

    I had a second try with masts further aft and equal sails. 12 m tall masts, and approx 2 x 36 sqm sails.

    Badger seems to have equals sails.

    I tried to locate the CLR (if I understood well from the forum) with Arne's rough method (see pics in my album, link in first post). I am not sure it is valid with a centerboarder though ??

    I have difficulties to find a way to increase the sail area by 150 % ! There is not much space between the sails and I need some space aft. Maybe increase the sail surface forward of the fore mast ?

    André


    Last modified: 29 Nov 2020 16:41 | Anonymous
  • 28 Nov 2020 08:32
    Reply # 9391024 on 9390257

    Hi Andre

    What a great design and how innovative!....I remember it well from when I was a much younger young designer recently graduated from the Westlawn School of Yacht Design in the US. I was very prompted to build it but never did. It became the precursor of the big trend in France of centerboarders. Patrick though was from Belgium and he died, fairly young few years latter.

    The design is somewhat dated, with the long overhangs etc, and today a would reconsider the stern daggerboard if I were to rig it as a Schooner, and aluminium wold be the way to go .....for me!

    I would see no reasons why you could not rig it as a junk rig but I would base my sail area calculations to start with on at least 135 and better, 150% of the original surface meaning main plus 150% genoa surface.



  • 27 Nov 2020 20:23
    Reply # 9390347 on 9390257
    André wrote:

    Hello all,

    The current circumstances are not favorable to boat projects, so I try to take advantage to build up the plans and improve the preparation for a conversion that will take place, hopefully, not too long down the road.

    I like this boat, a Trismus 37, centerboard with some keel, designed a while ago for ocean voyages. My project is for life onboard, and long distance on ... not that high budget. So I need simplicity for autonomy.

    I have been looking around on the site and am more and more convinced that my next boat (third after a 33ft sloop and a 43ft ketch) will be a junk rig. I am hence thinking of converting a Trismus 37 to junk.

    I would be happy to have some opinions given the characteristics of the boat ?

    After reading a recent thread about the conversion of a 36ft boat,  I am afraid 1 mast would have a sail a bit too large. Original has 65 to 75 sqm for 11.8m or 13.5m tall mast.

    I have tried to play with images pasting from images of Ron Glas (sorry for the blasphemy). Nothing serious in terms of calculations though.

    Positions of the masts I tried on the drawing are more related to the interior layout than on real data. I don't have much choice due to the centerboard position.

    So 2 masts, equal size or forward sail smaller ? I would prefer 2 equal masts to have identical sails.

    I try to put a link to pics of the original plans of a Trismus 37. First time I do that so I'm not sure.

    https://www.junkrigassociation.org/Sys/PublicProfile/
    46796359/PhotoAlbums/131656700

    Regards,

    André

    Hello André,

    It helps to put a shift/return in the middle of a long link like this, as I have done above.

    I think I would try to put both masts further aft. Perhaps the foremast goes through the exisiting forehatch, and the after mast goes aft of the double cabin doorway. This could mean that the sails are of equal size, or even that the after sail is smaller, making the rig a ketch, not a schooner. Maybe the sails could be of equal width, to share battens, but one of them could have more height than the other, to get the helm balance right (like Badger).

    Last modified: 27 Nov 2020 20:26 | Anonymous member
  • 27 Nov 2020 19:55
    Message # 9390257
    Anonymous

    Hello all,

    The current circumstances are not favorable to boat projects, so I try to take advantage to build up the plans and improve the preparation for a conversion that will take place, hopefully, not too long down the road.

    I like this boat, a Trismus 37, centerboard with some keel, designed a while ago for ocean voyages. My project is for life onboard, and long distance on ... not that high budget. So I need simplicity for autonomy.

    I have been looking around on the site and am more and more convinced that my next boat (third after a 33ft sloop and a 43ft ketch) will be a junk rig. I am hence thinking of converting a Trismus 37 to junk.

    I would be happy to have some opinions given the characteristics of the boat ?

    After reading a recent thread about the conversion of a 36ft boat,  I am afraid 1 mast would have a sail a bit too large. Original has 65 to 75 sqm for 11.8m or 13.5m tall mast.

    I have tried to play with images pasting from images of Ron Glas (sorry for the blasphemy). Nothing serious in terms of calculations though.

    Positions of the masts I tried on the drawing are more related to the interior layout than on real data. I don't have much choice due to the centerboard position.

    So 2 masts, equal size or forward sail smaller ? I would prefer 2 equal masts to have identical sails.

    I try to put a link to pics of the original plans of a Trismus 37. First time i do that so I'm note sure.

    https://www.junkrigassociation.org/Sys/PublicProfile/46796359/PhotoAlbums/131656700


    Regards,

    André

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