Boatspeed
from the Boating Info Center - New Zeeland

Best speed is achieved by ones ability to find the right combination of the
following variables.
Variables Out of Your Control
  • Variables You Control
  • Wind 
  • Waves 
  • Opponents action 
  • Course steered 
  • Sail trim 
  • Boat balance (including rudder/centreboard 
  • The key to boat speed is feel. Feel is achieved through a combination of sail trim,
    boat balance and course steered which results in the correct amount of weather
    helm feel for any given wind and wave condition.

    To Increase Weather Helm Feel By
    (or decrease by using opposite of below)

    The key to top speed is how you use your natural feel to mix these
    ingredients in the right combination. Once out on the race course this
    mix of course steered, sail trim and boat balance is the difference between
    being fast or slow.

    Natural feel can really only be learnt by time spent sailing (especially in small
    dinghies starting at an early age). A sailor with feel will automatically make
    adjustments without even knowing the reasons. The late starter may have to
    think why a certain adjustment is necessary.

    For the best results you need to combine natural feel with a good understanding
    of what is fast and the reasons some combinations work better than others.
    What is obvious is that variables - course steered, sail trim and boat balance
    are all completely dependent upon each other for best speed.

    Light wind Boat speed 0-5 knots

    Upwind: The key points are to increase weather helm and create efficient
    wind flow over sails. Body and helm movements must be super smooth so as
    not to disturb wind and water flow. It is critical to remain calm, both mentally
    and physically (this is not easy as you often have to remain in the same position
    for long periods).
    Use mast pre-bend and outhaul to flatten mainsail.
     

  • Tighter rig tension will pre-bend the mast (for dinghies)

  • or ease rig tension to power up head sail for racing keelboats.
     
  • Have both jib and main luffs eased to create a few horizontal wrinkles,

  • allowing the draft to move aft for better light air sail shapes.
     
  • Sheet both main and jib with twist to leeward on leaches to help wind flow.

  •  
  • Be careful not to over sheet the boom. Use the boom well off the centre line

  • in very light breezes and only when sure of your boat speed, attempt to
    sheet further inboard. Boom down for further drive.
     
  • Keep jib slot open and flowing, remember boom is further to leeward than usual.

  •  
  • Rake rudder aft and centreboard maximum forward to increase weather helm feel.

  •  
  • Position crew weight to leeward and forward to create more weather helm and

  • reduce wetted hull surface. Crew should be careful not to disturb wind flow in
    the slot between the jib and mainsail.
    Try to steer by watching wrinkles along the jib luff (on monotypes, the main)
    allowing them to be slightly back winding for best flow. Try to create correct
    weather helm feel by careful use of body movement. Don't allow the helm to go
    dead by flattening out leeward helm. Try to balance the boat for light airs using
    rudder and centreboard positioning, rather than having to use too much leeward
    heel to achieve the desired weather helm feel.

    Reaching: The same principles apply as for upwind, i.e. best wind flow by having
    luff wrinkles slightly backing, combined with good helm feel. For double handed
    boats the key is your use of the spinnaker and pole height combined with course
    steered.

    You need to position the pole higher when tight reaching as this opens up the
    spinnaker luff allowing you to point up higher into the wind. If your course is
    low then your pole height must also be low in order to keep the spinnaker filling.
    The helmsman must then decide just how low he can afford to steer and still
    fill the spinnaker. Good communication with the trimmer. The helmsman must
    be able to subconsciously feel the weight of the spinnaker sheet. The weight
    decreases to the point of the spinnaker collapsing, then the helmsman must
    steer a slightly higher course and maintain the balance between good speed
    and best course to mark. Using the variations in wind speed is critical to fast
    reaching legs i.e. pointing down in the puffs and up in the lulls.

    Running: In very light airs running utilizes the same principles as broad reaching
    or low course reaches, finding the right combination of boat speed versus best
    course to mark. As wind increases your gybing angles should become smaller,
    allowing you to steer more directly downwind.
     

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