New (cambered) sail for Footprints

  • 05 Mar 2012 19:01
    Reply # 848284 on 829776
    Deleted user
    Thanks for that suggestion. I will follow up on that batten option but I think for the time being and in the interest of getting the new sail on the boat by the Rally I will stick with the cedar battens. Yesterday I bought the 100mm x 3mm alloy tube for the yard which is going to be a huge improvement on the old timber yard and probably only a third of the weight of the timber, so in addition to improved performance from the sail it is actually going to be a lot easier to hoist.
  • 05 Mar 2012 05:56
    Reply # 847733 on 846948
    David Thatcher wrote:I would also like to replace my timber battens with alloy but there seems to be no suitable alloy extrusions of a suitable temper available so I will stick with what I have. 


    Ulrich have hard drawn (H8/T8) tube 50x1.5 that would work for you. However if your battens are greater than 5M you'd need to extend the tubes. You cannot however weld them as that would destroy the temper but one could sleeve and rivet. 50x1.5 Hard drawn tube is incredibly stiff, stiffer than the 50x2.2 T6 tube that I also have.
  • 04 Mar 2012 07:20
    Reply # 846954 on 842894
    Gary King wrote:
    Anthony Cook wrote:
    David Tyler wrote:Eight day:
    All of the panels and the yard sleeve joined together. The yard sleeve needs reinforcing at the ends, and at the window in the middle where the halyard attaches to the yard, and that slowed things down. The devil is in the details.
    Sleeving the yard sounds rather innovative.  Is there some cunning aerodynamic reason for doing so?
    What size tube is the yard David?
    See David's posting. "Massively heavy" doesn't begin to describe it - I think it's made from hearts of oak. David should qualify for automatic entry into the "World's Strongest Man" competition, hoisting that yard and a 16oz/sq yd Duradon sail into the air. I'm suggesting he gets a 5m length of 100mm dia x 3mm wall alloy tube, at 12.2 Kg.
  • 04 Mar 2012 07:08
    Reply # 846953 on 829776
    Arne,
    Before this session, I'd made three sails of this size, and they each took around 7 - 9 days or so.
    Using an edge-sewing technique, and not rolling each panel to pass under the arm of the machine, certainly speeded up the assembly. Importantly, it also made it possible to do the assembly in a room of 7.2m x 6.6m, whereas a room twice the length of the rolled panel is needed if stiff sailcloth is being assembled by "sailmaker's methods".
  • 04 Mar 2012 06:59
    Reply # 846951 on 842789
    Anthony Cook wrote:Sleeving the yard sounds rather innovative.  Is there some cunning aerodynamic reason for doing so?
    I made a sail of this size about nine years ago for Nemesis, owned by David Nisbet, and put on a sleeve for the yard. He spoke well of it.
    We've used a full width of 92cm cloth for the sleeve, so the ratio of sleeve width to yard diameter is about 5:1, giving a smooth, round, clean, faired-in leading edge, which I believe is beneficial aerodynamically. On top of that, the sleeve carries all the loads perpendicular to the yard, meaning that there is no reliance on tracks, sliders, boltropes, eyelets, lashings or the like. Only lengthways tensioning is needed.
  • 04 Mar 2012 06:37
    Reply # 846948 on 829776
    Deleted user

    The two Davids have laboured long and hard. Footprints new sail is just a few hours away from completion but Tysties sail is still a pile of rolled individual panels. A few days off for both of us and then back to work assembling Tystie's sail.

    As I have been watching Footprints new sail take shape on the floor of our lounge I am beginning to fully appreciate the vast difference between my former flat panel sail and this new cambered panel sail. I am now very much looking forward to trying out the new 'sports' version of Footprints.

    There is a bit of work still to do on spars. All of my cedar battens need to be lengthened, an extra batten made and something done with the yard. After delivering David Tyler back to Tystie I brought the solid timber yard from Footprints home to shorten and reshape it. It is however so massively heavy that I think in my lunch hour tomorrow I shall be paying a visit to our local aluminium suppliers to check out what they have in the way of suitable alloy tube for a completely new yard. I would also like to replace my timber battens with alloy but there seems to be no suitable alloy extrusions of a suitable temper available so I will stick with what I have.

    Anyway back to work tomorrow for a few days to bring in some extra cash to pay for these important things in life.

     

     

  • 03 Mar 2012 13:56
    Reply # 842912 on 829776
    Anonymous member (Administrator)

                                                                               Stavanger, Sat

    David, your progress sounds very good, in particular considering you are making two sails, over 100sqm together.

    I kept record of the time I used when I made Malena’s first cambered sail (32sqm) in 1994: I made the sail in 6 days, spending 40hours. I used every time-saving tricks I knew; the 5 lower panels were identical and I used the dead-easy amateur method a to join the batten panels. With the canvas coming in 160cm width, that was wide enough to span one batten panel, rounding plus batten pockets and all. Only in the two top panels did I have to join two widths. I bet the total length of seams were shorter than on most junk sails of that size. I had only made a couple of small jibs plus a simple Ljungström sail before so this was still quite a step ahead.

    The roping took me eight hours sharp, using the rope type roping (no webbing involved). This sounds incredibly fast, but since the method only involves groups of 3-4 stitches with intervals of 12 – 15cm, that speeds up the progress with a factor of 5 – 10, I guess. What consumed much time was splicing in all the hoops for the batten ends to rest in. Those six battens have 12 ends and with two splices per hoop, that meant 24 splices! In the four corners of the sail I didn’t make hoops. I just let the bolt rope follow the edge of the sail around the corner and then placed one group of stitches 2-3cm on each side of the corner. This roping has held up until the sail was finally scrapped this autumn.

    Good luck with your work; I am looking forward to seeing the result!

    Arne

    PS: Could I suggest that you fit telltales to the leech of the sails?

    PPS: To have a look at that Ljungström sail, check "20110722 The poor man’s Ljungström Rig", found under the letter section in "my" folder.

    Last modified: 03 Mar 2012 18:01 | Anonymous member (Administrator)
  • 03 Mar 2012 13:11
    Reply # 842894 on 842789
    Deleted user
    Anthony Cook wrote:
    David Tyler wrote:Eight day:
    All of the panels and the yard sleeve joined together. The yard sleeve needs reinforcing at the ends, and at the window in the middle where the halyard attaches to the yard, and that slowed things down. The devil is in the details.
    Sleeving the yard sounds rather innovative.  Is there some cunning aerodynamic reason for doing so?
    What size tube is the yard David?
  • 03 Mar 2012 10:07
    Reply # 842789 on 842723
    David Tyler wrote:Eight day:
    All of the panels and the yard sleeve joined together. The yard sleeve needs reinforcing at the ends, and at the window in the middle where the halyard attaches to the yard, and that slowed things down. The devil is in the details.
    Sleeving the yard sounds rather innovative.  Is there some cunning aerodynamic reason for doing so?
  • 03 Mar 2012 08:02
    Reply # 842723 on 829776
    Eight day:
    All of the panels and the yard sleeve joined together. The yard sleeve needs reinforcing at the ends, and at the window in the middle where the halyard attaches to the yard, and that slowed things down. The devil is in the details.
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