Advice? Downwind sailing in strong winds

Discussion in 'Laser Talk' started by Johanna, Aug 31, 2012.

  1. Johanna

    Johanna Laser 4.7/Radial

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    Hi everybody!

    As a fairly new laser sailor, i was wondering if you had some advice about sailing downwind in a laser. Last sunday i went sailing a race at my local club with some other teenagers but especially when i was tired (the wind was around 6 bft) i found it really difficult to handle my boat and avoid capsizing. (I capsized and capsized again after like 30 seconds I righted the boat) So i was wondering if you could help me, and maybe other (new) laser sailors, with this problem as the boat is quite unstable when i'm sailing downwind.

    Somethings about me that may help:

    Rig: 4.7
    Lenght: 1.75m
    Weight: 65 kg
    Age: Almost 16
    (I know i should be sailing with a radial rig, but i find it hard to control the sail (because i'm just not strong enough yet, and i'm having some physical problems with my knees and wrists))

    Thank you a lot in advance!!
    Johanna
     
  2. laserxd

    laserxd Member

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    Check out this video, Marc is always really fast in heavy air, watch how we works the boat and easily gains a great deal on the rest of the fleet

    downwind you need to overtrim the main, if the main is at 90 degrees or more the boat will roll to windward

    when you gybe, you need to fully commit and do so with speed

    remember that the faster you go the less force there is on the sail, it makes it easier to keep the boat stable and to gybe,

    you don't want to turn too much through the gybe,

    when you come out of the gybe you want to be sailing low, if you come out on a beam reach you'll capsize

    keep the boat stable, cunningham off (it makes the boat squirly downwind), vang off (dump the excess power)

    sit back in the boat to keep the bow up, if you dig into a wave the rig will load up and make the boat unstable

    if you do capsize, head the boat upwind before you right it

    its easy to capsize so don't get discouraged or upset when you do,

    stay positive and you'll spend less time in the water,
     
  3. Alex/Steve

    Alex/Steve Member

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    Hi Johanna

    All of the above

    Plus maybe a bit more centreboard (down) than others seem to use

    We think it stops boat from "sliding" under you

    Alex/Steve
     
  4. CoachK

    CoachK Member

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    One reason you are capsizing is that there is too much twist in the top (leach) of the sail. When the leach goes forward of the boom it can easily cause a capsize. Look up at the sail as you are sailing downwind. Do you see the leach flicking forward? Putting more vang on will help stabilize the boat. I never take vang all the way off. Even in light winds some vang (to keep the rig from bouncing) is good. Just take the slack out.

    Two great laser sailors - Ben Richardson and Clay Johnson contributed downwind sailing tips in light - heavy wind on my blog www.centerofeffort01.blogspot.com.
     
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  5. laserxd

    laserxd Member

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    basically if you're sailing with the boom at 90 degrees, the leech at the top of the sail will be past 90 degrees causing a force to windward, sheet in slightly to flatten the boat

    I play the vang depending on the conditions, vang can make a huge difference, its sorta like the gas pedal
     
  6. tonyquoll

    tonyquoll Member

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    Agreeing with CoachK: crank the vang (kicker) on to keep the boat stable downwind. If you've got an original 3:1 system, then go upwind, pull the mainsheet tight, then quickly yank the vang tight. Then you can ease the main, bear off and get downwind in relative safety.
    Having the vang tight downwind does seem to make the boat slower; so as laserxd says; play it depending on the conditions.
     
  7. AlanD

    AlanD Former ISAF Laser Measurer

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    3 things all mentioned above
    • Don't let the boom out too far (80 degrees max)
    • Don't ease the vang too much
    • Don't raise the centreboard too much
    In heavy breezes, a Laser will go into a death roll pretty easily so doing the above will minimise the situation.

    Other things you should be doing spending as much time looking backwards as forwards, to anticipate the gusts hitting you. Knowing when they will hit will allow you to get ready for them.
     
  8. torrid

    torrid Just sailing

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    You're going to go swimming - don't let it discourage you. It takes time to learn, especially moving your body with the wave motion.
     
  9. monkey_feet

    monkey_feet Arlington, TX

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    practice practice practice. When I bought my Laser a few years ago, I was very experienced in the MC Scow and several other classes and still spent a fair amount of time swimming!

    Don't let yourself get frustrated.
     
  10. madyottie

    madyottie Apprentice

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    One thing nobody seems to have mentioned is sailing by the lee. In near survival winds its the safest way. Sheet the boom in to around 75-80 degrees, (so about 12" - 18" in from 90 degrees), and turn until the wind is just past straight behind the boat. Get it right and you can feel the boat suddenly get very docile and easy to control.

    The hard part is getting to that stage. It's tricky turning downwind at the right rate without either digging the boom in, or rolling out to windward. Maybe use a little less vang than you might think you need, this will allow you to steer slightly easier.

    The main point though, whether for speed or safety, is to avoid running straight with the wind. Doing that is a recipe for swimming, as the sail moves around, and the boat gets very unstable.

    See if you can find the Rooster Sailing online article on downwind sailing, it explains this far better than I can.
     
  11. laserxd

    laserxd Member

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    That's true, sailing on a broad reach or by the lee will help stabilize the boat, its easier to stay in a straight line
     
  12. Int. Sailing Academy

    Int. Sailing Academy Member

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    Here's the theory behind the capsizing and preventing death rolls:
     
  13. tonyquoll

    tonyquoll Member

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    The theory of preventing death rolls is to eliminate forces that might cause the boat to roll:
    The reason you keep the vang (kicker) tight, is to stop the sail twisting. Twist means that some of the sail forms an inclined plane, which generates a vertical component of force and THAT will cause the boat to roll. Theoretically a flat sail will not cause the boat to roll.
    Going onto a broad reach means you have to hike out to balance the sail's force. I find that in strong winds it's easier bear off from a reach onto a run and move in to sit on the deck of the boat. I'm talking about gusts over 25knots. Having the sail at any angle other than 90 degrees means you are generating a side force across the boat; which causes the boat to roll. Theoretically a flat sail at 90 degrees will not cause the boat to roll.
    Sailing by the lee means you have a curved sail, and have angled the sail and are sailing at a bearing to induce a flow along the leeward side of the sail. This is faster than running square, because a larger force is generated by bending the wind than by catching it. When the wind is gusty, this force suddenly changes, which causes the boat to roll. When the wind is shifty, either the flow suddenly becomes turbulent or you suddenly gybe. So either the boat will roll or you will have to duck and try not capsize in the gybe. Theoretically, sailing by the lee is very hazardous during strong winds.
    In the video above, one comment heard is "the sailors are constantly moving their body weight from side to side, and trimming their sails in and out." I draw your attention to Rule 42.2 Prohibited Actions: "these actions are prohibited: a) pumping: repeated fanning of any sail by pulling in and releasing the sailing... b) rocking: repeated rolling of the boat, induced by (10 body movement, (2) repeated adjustment of the sails"
    To put it bluntly, I think the advice given is illogical and illegal.
     
  14. CaptainAhab

    CaptainAhab Active Member

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    Tony,

    Rule 42.2 in effect describes cheating. All of the motions (kinetics) are also required to sail the boat. Rule 42.2 violations are usually obvious to the trained observer. Rapid trimming and movement to prevent capsizing is obviously not a Rule 42.2 violation.

    Based on your comments roll tacking/gybing would be illegal. The Laser class is actually pretty lax about upwind kinetics. They even gave it the name torquing, to help legitimize it.

    In my experience wave action is often the precipitating force that causes death rolls. The rear quarters of the Laser can really dig into a wave. This causes a substantial disruption in hull and sail position.
     
  15. tonyquoll

    tonyquoll Member

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    Constantly rocking the boat and pumping the sail does nothing to help stop capsizing; it is cheating and propelling the boat along. The video above shows a fairly steady 10knot breeze and barely visible waves; these are not death roll conditions and the sailor's actions do not seem related to catching waves. Surely it would be better advice to keep the boat steady and under control.
    Roll tacking is not illegal, but Rule 42.3 (e) prohibits "repeated tacks or gybes unrelated to changes in the wind or to tactical considerations."
    "Torquing to change the fore and aft trim of the boat in phase with the waves" is permitted; but excessive torquing causing the leach to flick (pumping) and torquing on flat water are not. See: http://www.laserarg.com/Rule42.pdf
     
  16. Int. Sailing Academy

    Int. Sailing Academy Member

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    Hi Tony,


    Tony I apologize if my video was not educational for you, hopefully this helps;
    you are correct about eliminating forces that would keep the boat from rolling.. However, boom vang on it's own does not solve your problems. Adding kicker downwind in breeze will make your boat very unstable, difficult to steer and likely to head up from the added weather helm. The perfect balance is reached by a looser vang setting and maintaining a trimmed in sail. As I mentioned in the video, the important part on the sail to keep balanced is your leech, NOT the boom.
    One must be careful, with a loose vang if your boom ever gets out to 90 degrees, you will find yourself swimming quickly.
    When sailing by the lee, the flow over the leeward side of your sail is called reverse flow. Reverse flow adds force to the sail, making it substantially more powerful and faster than running. When your boat is moving fast, it is easier to keep in a straight line. If you are afraid of getting out of control, try applying pressure to the leeward deck, keeping your boat flatter which will add more force to leech of your sail making you more stable. do not sail by the lee sitting on the windward side with your leg hooped under the strap and carrying major windward heel as this is hazardous especially in shifty conditions because it releases forces from the sail, and promotes poor reverse flow. Also, make transitions with your sheet and body to avoid digging the bow into a wave. digging the bow is a leading cause of death rolling, so technically I do think that constantly rocking the boat and pumping the sail does help stop capsizing.
    Lasers and rule 42 are an interesting topic. There are lots of things to learn here, especially if your new to the boat.
    Pumping is permitted downwind as long is it's not repeated.. Juries look for the bow to be out of the water (surfing conditions, which are shown in the video) Juries look for repetition in the form of more than 1 pump/body movement/rock per wave. When using your body and trimming the sails, the boat must respond by changing direction, which is why the boat goes between broad reach and by the lee with every movement. If your boat rocks, but does not change directions, it will raise a flag.
    For people who are not familiar with surfing downwind in Lasers, I would recommend practicing changing directions without using tiller movements. ie sheeting out and leaning to leeward, then sheeting in and moving your body back and to windwards. These are LEGAL manoeuvres and will contribute to an increase in forces on your sail, and speed down the waves. Every transition accelerates the boats and often allows you to jump over wave sets. At World class events, the race is won downwind.
     
  17. torrid

    torrid Just sailing

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    When surfing downwind, you are constantly adjusting the mainsheet and your body position to stay on a plane. It's not cheating, just good sailing.
     
  18. tonyquoll

    tonyquoll Member

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    This thread begins seeking advice to keep a boat upright while sailing downwind in strong winds. For a novice sailor, I maintain that the safest approach is to set a flat sail with vang/kicker tight, and run square with the sail out to about 90degrees.
    The advice about sailing by the lee, pumping and rocking etc may be faster for experienced sailors in a race, but that's not the question. Sailing by the lee is tricky, and best practiced in light, steady winds. It seems reckless to suggest to a beginner to sail along at the point of gybing in strong winds.
    The link I provided above has provides excellent interpretations of what is illegal propulsion.
    As an example of someone being penalised for much less pumping than featured above; watch Xu in action from 18:30 to 19:10 in the Olympic Laser Radial Medal race:
     
  19. CaptainAhab

    CaptainAhab Active Member

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    That video is really good. There is plenty of movement from all of the girls. The Chinese sailor got caught by the flicking of the leech. It is apparent if you look for it. She is easing out enough to unload the leech, then a roll and a quick trim, reloading the leech. She was much faster downwind even after taking the penalty turns. Great race.
     

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