Sailing by the lee - how to

Discussion in 'Laser Talk' started by jonah77, Oct 23, 2012.

  1. jonah77

    jonah77 New Member

    Likes Received:
    0
    Trophy Points:
    1
    Hi. I've seen the rooster sailing by the lee page, but still can't picture this. How do you sail by the lee without gybing? If I head downwind, sheet out, then what??
     
  2. racinglasers

    racinglasers Member

    Likes Received:
    4
    Trophy Points:
    8
    Takes a little practice and daring ..... on a lightish day just let the main out and keep bearing off til you are by the lee .. get your tell tails flowing backwards from the leach to the luff ...... heeling the boom up a bit ....... the key is getting airflow over the sail backwards from what is "normal" ..... its fast!
     
    • Agree Agree x 1
  3. Mrs. P

    Mrs. P Member

    Likes Received:
    11
    Trophy Points:
    18
  4. jeffers

    jeffers Active Member

    Likes Received:
    31
    Trophy Points:
    28
    Basically you sheet out with the boom around the 90 degree mark and then bear away until you see the flow reverse over the sail. This can be spotted using your tell tales. If the leech starts to flick be very careful as you are right on the point of gybing.

    You should practice on a light-ish day (but not too light) so you can see the effect of the wind.

    Be prepared to get wet though. Once you have it sorted it is a very useful weapon to have when sailing downwind especially in mixed fleets.
     
    • Agree Agree x 1
  5. laserxd

    laserxd Member

    Likes Received:
    23
    Trophy Points:
    18
    usually when you're sailing on a run the tell tales will be fluttering, if you head up you'll be on a broad reach, head down and you'll be sailing "by the lee" ie reverse flow on the sail,

    to get by the lee flow, keep the boom out 90 degrees in light-medium conditions, head down, raise the centerboard so the top edge is around 4-6 inches off the deck, don't raise it too much or you'll slip sideways

    as you head down you'll see the flow on the tell tales reversed and you'll feel speed/power as if you were on a reach,

    while you're learning, stay alert and low in case of an accidental gybe.

    If you keep sailing deeper until the sail gets back winded then you will get a good idea how far you can go by the lee,

    if you're about to gybe you can either go through with the gybe or head up to stay on the same tack.
     
    • Agree Agree x 1
  6. fat-n-old

    fat-n-old Member

    Likes Received:
    3
    Trophy Points:
    18
    ....and the little hawk wind indicator (if you have one) forward of the gooseneck, starts spinning like a crazy thing. :D
     
    • Like Like x 1
  7. jonah77

    jonah77 New Member

    Likes Received:
    0
    Trophy Points:
    1
    Thanks all, will have a try at the weekend.
     
  8. torrid

    torrid Just sailing

    Likes Received:
    55
    Trophy Points:
    48
    If the sail fills and you get moving on the lee, it is quite stable and can actually be quite difficult to gybe.
     
  9. Wavedancer

    Wavedancer Upside down? Staff Member

    Likes Received:
    137
    Trophy Points:
    63
    A vane on the top of the mast really helps to see what's going on.

    As laserxd pointed out, it's kind of fun to see how far you can go by the lee and then head up to prevent a jibe. When you start playing this game, do it in light winds, for obvious reasons
     
  10. jeffers

    jeffers Active Member

    Likes Received:
    31
    Trophy Points:
    28
    Had this situation at the weekend at our annual Laser open event. The boat goes so far then will not go any further. All you can do is ride out the gust, gybe as soon as possible and then come back to the right line at a better angle. Much faster than forcing the issue and going for a swim.
     
    • Like Like x 2
  11. fat-n-old

    fat-n-old Member

    Likes Received:
    3
    Trophy Points:
    18
    Which is fine if you have the room to do it :D
     
  12. torrid

    torrid Just sailing

    Likes Received:
    55
    Trophy Points:
    48
    Usually happens to me when I'm trying to round the leeward mark.
     
  13. jeffers

    jeffers Active Member

    Likes Received:
    31
    Trophy Points:
    28
    Correct....if not capsize or tack round as appropriate...then curse the RO for putting a mark in a confined space when it is blowing hard!
     
  14. Marineboy95117

    Marineboy95117 marineboy95117

    Likes Received:
    0
    Trophy Points:
    1
    Why? Perhaps indicating lots of turbulence at that spot (forward of the gooseneck) while sailing by the lee.... Hmm...
     
  15. Strangler

    Strangler Member

    Likes Received:
    2
    Trophy Points:
    8
    Turbulance or a vortex? Is there an aerodynamicist in the house who can shed some light on this?
    Aren't vortices essential for lift?
     
  16. CoachK

    CoachK Member

    Likes Received:
    9
    Trophy Points:
    8
    You have flow across both side of the sail when you are BTL - hence the spinning wind indicator.
     
  17. tonyquoll

    tonyquoll Member

    Likes Received:
    4
    Trophy Points:
    8
    am just learning to sail by the lee, by using a GPS to display speed at various sail positions in a steady 10knots breeze.
    Using the sail square as a baseline; 8km/h with full shape and vang/kicker eased.
    Sheeting in until windward tell-tales flows: boat slows, until:
    tell-tales on leewide side of sail flow; 10km/h.
    I found I can sail at the same angle to the wind, gybe and let boom go far forwards; full length of 12.5m mainsheet out, and then get tell-tales flowing on an extreme broad reach. 10km/h.
    In light steady winds, I could achieve the extreme reach more easily with less loss of speed in the process of doing it.
    However, in gusty 20knots the extreme reach drives the mast to windwards and the swerving and work done to stop death-rolls is inefficient and costs speed.
    This image shows computer-generated theoretical flows over a sail:
    [​IMG]
    from: http://syr.stanford.edu/SAILFLOW.HTM
    If you imagine this is sailing by the lee on starboard tack, there would be flow going past only the aft/starboard side of the wind indicator, causing anti-clockwise spin.
     
  18. laserxd

    laserxd Member

    Likes Received:
    23
    Trophy Points:
    18
    good find, notice how the flow reacts off the trailing edge
     
  19. Roadie

    Roadie Member

    Likes Received:
    2
    Trophy Points:
    8
    Have a good set of telltales (especially have a telltale up in the top third of the sail) and a wind-indicator so you can really tell where the wind is from. Go out on a light/medium wind (8 knots ish) with steady wind that's not shifty. Bear away onto a dead run and get settled, make sure you have on foot hooked under the toe strap and locked against the inside of the cockpit underneath you. This means you can move onto other side quickly if you need to. Have the sail a little past 90 degrees out and the vang soft with quite a lot of twist, but not loads. Gently bear away by the lee and be prepared to shift your weight to windward if needed. The sail is very hard to gybe once you have good laminar flow over both sides of the sail. If the boat roles to windward the bear further by the lee slightly, let the sheet out a touch and at the same time push off the inside of the cockpit and semi stand up towards the other gunnel quickly.
    Hope this helps.
     
  20. dingyj #22

    dingyj #22 Member

    Likes Received:
    8
    Trophy Points:
    8
    All I can say is over about 12 to 15 kn it takes a big set...im still growing mine.
     

Share This Page