Jump to content

patzefran

Members
  • Content Count

    129
  • Joined

  • Last visited

Posts posted by patzefran

  1. 4 hours ago, gspot said:

    Lots of multis have a fractional hounds/Jesus shackle, with spinnaker and/or screacher attachments above that. Depending on the stoutness of the mast section, it may require runners to support the mast at the spinnaker and/or screacher attachments, especially if the main sail is reefed, to prevent the mast section above the hounds/Jesus shackle from inverting.

    Runners are mainly useful to prevent buckling of the mast section under the hound, when sailing downwind with spinaker ore code 0. Indeed, on a multihull, longitudinal distance between the chainplates and the mast step is much lower than lateral distance. Downwind, this induce a very high compression load on the lower mast column. Mainsheet tension help to lessen this compression but this need to control the gusts only by releasing spinaker sheet, not the mainsail. I have experimented this on my 20' Strike Trimaran , the (Tornado) mast has collapsed when I released the mainsheet to control a big gust. Since I use runners attached to the hound and outer aft beam, no more problems !

    • Like 1
  2. I am looking for one of the first French F 40, Jycoat, Alias Colibri, Caisse d'epargne ... she is a Gilles Ollier design , scaled version of Phillippe Jeantot's Credit Agricole (Quebec St Malo winner). I owned/sailed her from 1990 to 2006 under the name Fantasia and sold her in 2006 to two US owners. They sailed her Across the atlantic to Miami, then to Bend,Oregon, by road. According to last news I got some years ago she was still  in a back yard in Bend. Please contact me if you know his present location and owner, some people are eventually interested to bring back her in France.

  3. On 1/4/2022 at 6:43 PM, multihuler said:

     I brought a house in Washington NC, where I will bring my fleet, 2 Formula 40s, soft wing c class and a Newick.

    There will be  fund raising to support a multihull race/ gathering. Pitching it to the city, including a shrimp cook off, fly in , and sail in. Should be fun.

    Also looking for that museum location, how cool it would be if it became a stable of C class boats.

    Anyone and everyone is invited to sail the F40 Skateaway,  100% of proceeds will go to the event.

    Cheers, 

    Stephen 

    Resized_20211010_172232(2).jpg

    I am looking for one of the first F 40, Jycoat, Alias Colibri, Caisse d'epargne ... she is a Gilles Ollier design , scaled version of Phillippe Jeantot's Credit Agricole (Quebec St Malo winner). I owned/sailed her from 1990 to 2006 under the name Fantasia and sold her in 2006 to two US owners. They sailed her Across the atlantic to Miami, then to Bend,Oregon, by road. According to last news I got some years ago she was still  in a back yard in Bend. Please contact me if you know his present location and owner, some people are eventually interested to bring back her in France.

  4. 1 hour ago, MFH125 said:

    It's hard to convince people.  Humans have bad intuitions about drag.  No matter how many times I look at this picture, the fact that these two profiles have the same drag feels wrong to me.  Probably the very different volumes tricking my eye.

    Screenshot_20220104_081738.png.f46cf0738608eb926c2d93140e1d6e76.png

    CD is related to a reference area, Drag is proportional to S x CD ! Likely the reference area are not the same

  5. 8 hours ago, SCARECROW said:

    lower one will have marginally less effect on mast rotation.

    In the first image the purchase down to the traveler is pushing the boom forward encouraging the mast to rotate while the sheet at the front is pulling it aft doing the opposite.

     In the second the line running from the boom to the mast will pull the boom fwd and become a tight hypotenuse locking the mast in its rotated position. 

    Except the pull on the mast is only 1/6 the tension on the traveler, so the result depends on the angle of the aft sheets !

  6. 3 minutes ago, patzefran said:

    I think you must feel it with your nose and enter the data in the app !

    Sorry, I spoke about phone apps., IMHO the performance analysis softwares (e.g. GPS action replay) can rely only statistical analysis of windward tracks, wind direction used is the mean of port and starboard tracks. I think It is not very accurate and don't account on wind shift. In GPS action replay you can also enter the wind direction.

  7. The geometrical Ackerman model showing a boat turning with the hull(s) tangent to circular path and aligned with velocity vector is wrong !

    To turn the hulls need a centripetal force which is created by the lift of the hulls and appendages, and they need an angle of attack to the flow.

    Only model right is Tom Speer's one which take's into account the lift of hulls and appendages !

  8. 1 hour ago, he b gb said:

    Thanks Miz and Pat, I’m pretty happy with the performance and it’s funny but it feels faster than 9.5 kts. I think it needs short battens to fix the hook on the leeches.

    According to the length , she will likely reach over 15 kt in right conditions. The control with a single rudder on the pod could be somewhat tricky !

×
×
  • Create New...