Colvin Gazelle

  • 21 Nov 2018 13:45
    Reply # 6922613 on 6879165

    Re double sheets: They really need.to be attached forward of the leach to  prevent them from tangling with the ends of the battens and the sheets on the other side. Double sheets are also quite useful offshore to allow rigging of preventers to help the sail stay out when the wind is light and there's a swell tossing the wind out of the sails. It also helps keeping the foresail out when the wind gets too far aft before you get dead downwind and need to lower it. See attached pictures.

    Dave

    2 files
    Last modified: 21 Nov 2018 13:57 | Anonymous member
  • 20 Nov 2018 21:23
    Reply # 6916375 on 6916366
    Arne wrote:

    When David Ty. changed the rig of Tystie from the first fanned sloop JR to soft wing ketch, I think he found that double sheeting worked best when attached to the leech end of the battens. It makes sense to do the same to the HM sails I have drawn for the Gazelle.

    What do you think about it, David?

    Arne

    Yes, I was thinking exactly that, and was just about to write it! The mainsail needs sheeting a bit closer than the foresail, so port/stbd sheeting makes sense, and I got fewer tangles with sheeting attached at the batten ends than is usually the case with sheeting attached further forward on the battens.
    Last modified: 21 Nov 2018 08:01 | Anonymous member
  • 20 Nov 2018 21:14
    Reply # 6916366 on 6879165
    Anonymous member (Administrator)

    When David Ty. changed the rig of his Tystie from the first fanned sloop JR to soft wing ketch, I think he found that double sheeting worked best when attached to the leech end of the battens. It makes sense to do the same to the HM sails I have drawn for the Gazelle.

    What do you think about it, David?

    Arne

    Last modified: 20 Nov 2018 21:20 | Anonymous member (Administrator)
  • 20 Nov 2018 20:48
    Reply # 6916316 on 6916308
    Anonymous wrote:

    Maxime, does this boat have davits capable of carrying the mainsheet blocks?  If not, you'd need a boomkin of some sort, to get the sheets clear of the leech.


    Hi David,

    I'm looking at more than one Gazelle at the moment. Here's the one that best fits geographically: https://www.yachtworld.com/boats/1973/colvin--42-gazelle-3140539/

    It has solar panels on davits, so I think I'd have to continue to use double-sheeting.

  • 20 Nov 2018 20:44
    Reply # 6916312 on 6916229
    Anonymous wrote:
    Max wrote:


    One question (maybe stupid): On your drawings, there are black lines leading from the mastheads down to positions aft of the current masts. What do those lines mean? (image attached)

    Max

     

    I picked them from the original sailplan. I thought they were shrouds, so copied them, just as with the top stay between the masts  (and the forestay and jib).

    Arne


    Right! It was a stupid question after all. I looked at them without understanding for a long time, then finally understood just a few minutes after sending.

  • 20 Nov 2018 20:41
    Reply # 6916308 on 6879165

    Maxime, does this boat have davits capable of carrying the mainsheet blocks?  If not, you'd need a boomkin of some sort, to get the sheets clear of the leech.

  • 20 Nov 2018 18:21
    Reply # 6916112 on 6879165

    That's great stuff, Arne, thanks a lot. I think such a sail plan would be a good first step forward, at a much lesser cost, risk and hassle. Balanced and distributed just like the Colvin plan + camber + easier-to-manage sails and running rigging.

    One question (maybe stupid): On your drawings, there are black lines leading from the mastheads down to positions aft of the current masts. What do those lines mean? (image attached)

    EDIT: Hah, I think they're the stays. It was a stupid question after all!

    Max

    1 file
    Last modified: 20 Nov 2018 20:08 | Anonymous member
  • 19 Nov 2018 17:04
    Reply # 6914325 on 6879165
    Anonymous member (Administrator)

    Although I fancy the yawl rig, I can understand people’s reluctance to tearing down a fully operational rig, with masts and all. In case one has a good original rig and just wants to improve the performance of it to windward, and do away with some sheet tangles and reefing issues, here I have come up with two new sails for the existing rig.

    I would give the foresail 10% camber and the mainsail 8%. The wider gap between the two sails may be enough to have central sheeting on the foresail, I don’t know.

    Anyway, it could be an idea to increase the balance in both sails a bit at boom level. This will let the sails be canted aft a little bit, which is the best vaccination against sheet tangle.

    I would do away with the euphroe (spells?) sort of sheet and rather pick one from PJR or from Junk Rig for Beginners.

    Have a look.

    Arne

    PS:For those of you who are new to the JR and this group, I can tell you that I have made the sails and sailed with four boats with variations of this rig, based on the originally flat Hasler-McLeod sail.
    These sails, with camber, are now well established and fully operational:

      -  They are fairly easy to make, with several panels being identical.
     
    -  They perform well to windward, with their baggy panels (since 1994).
      -  When set with the luff and leech vertical or even tilted a tiny bit aft, they are very resistant against sheet tangle.
      -  They reef without problems, and perform and behave well when reefed. The Johanna-sheeting, shown in 'Junk Rig For Beginners' is helpful in controlling the twist when reefed.
      -  The fanned 3-panel top section is effective to windward. I have tested my two last boats with only three panels set, and we go to windward really well. The two last boats have even proven to tack and sail to windward with only two panels set, but with quite wide tacking angles. Not every boat will do that  -  Frøken Sørensen and my present Ingeborg are really good.


    Last modified: 19 Nov 2018 19:50 | Anonymous member (Administrator)
  • 19 Nov 2018 01:08
    Reply # 6913264 on 6879165

    David Tyler makes a very good point about available sections for mast yard etc. The hurricane rated flag poles seem like a very appropriate solution for the masts and most aluminium sections come in 5 or 6 meter lengths so anything over that require splicing or wooden extensions socketed into the aluminium.

    On Arcadian we had a 700 sq ft main and a 500 sq ft foresail. Most of the troubles came from the mainsail with numerous broken battens, it was also hard work getting the sail up, even with an electric winch and four part halyard.  For this reason I would tend to recommend a ketch rig with a mainsail of 450 to 500 sq ft and a mizzen of 300 to 350 sq ft. This would move the center of effort of the sailplan slightly forward from David Tyler's plan but leaving the mast positions as he suggests. It would mean a mainsail with a higher aspect ratio but still achievable.

    All the best with the project, David Webb.

  • 18 Nov 2018 22:18
    Reply # 6913156 on 6912836
    Anonymous wrote:

    Max, the Gazelle is a good sailing boat as is, but lacks the drive upwind to push through any appreciable sea state. Tweaking the sail design to get more power close hauled would do wonders for performance offshore. Sailing this boat is all about balance, with two mast it's quite easy to keep her dialed in. One can even get half a panel reefing using the lazy jacks pick up (or not) the outboard end of the sail. My complaint against the jib is having to go out on the sprit to furl it in heavy weather. 

    Arne,  the jib is essential for balance. Could it be replaced by a raked forward junk sail in the bow? I don't know how to figure if it would get that sail far enough forward to balance.


    Thanks for all these responses, Dave, David and Arne.

    I'm not allergic to a jib, especially if it can be rigged in such a way as to not require a trip to the bowsprit, using a block at the end of the bowsprit, or a roller-furler.

    Seems like there's no way to spread as much sail area as low-down without using the jib.

    It might ultimately be a good idea to make radical changes to the rig, but one might first try using cambered sails of roughly the same area as the original rig, on the original masts, with the jib.

    I rather enjoyed sewing up sails for my first Gazelle, even if I never got to use them, so I wouldn't mind sewing up a more conservative rig experiment before moving on to major surgery. If I can reuse some of the battens and change none of the standing rigging, even better.

    Last modified: 18 Nov 2018 22:34 | Anonymous member
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