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Sail trim and balance 2013 draft
This document discusses sail trim and balance. It explains the two modes of sailing - push and pull, with pull mode being when the sail is in flow. It identifies the three sources of sail power as angle of attack, draft, and twist. It describes the primary controls for the mainsail and jib/genoa and how they affect angle of attack, draft, and twist. It discusses balance and how sail trim impacts heel. Finally, it provides sail trim recommendations for light, moderate, and heavy wind conditions.
Sail trim and balance 2013 draft
- 1. Sail Trim andBalance Sail Trim and Balance with Kristen “kb” Berry
- 2. Sail Trim andBalance • The Big Question • One Language • Two Modes • Three Sources of Power • Controls • Balance • Putting it all together
- 3. What makes aboat go?
- 4. Let’s Develop a CommonSail Language
- 5. One Language • Mostsails have three edges • Most sails have three corners
- 6. One Language Head Leech Luff Clew Foot Tack
- 7. One Language LUFF Draft Chord Leech Camber
- 8. What are the TwoModes of Sailing? Two Modes of Sailing? •Fast and Slow? • Cruising and Racing? •Upwind and Downwind?
- 9. TWO MODES PUSH PULL
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- 11. Push Mode • Sailblocks the WIND wind. Creating high pressure on windward side • More wind = more power H H LL • More area = more power
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- 14. Pull Mode • Attachedair WIND flows over both sides from leading to trailing edge • Outside air flows faster because of L H camber H L • Creates heel & forward force
- 15. Pull Mode -Keel Lift Keel Lift • Keel lift works the same way, below the water. L • Water flows over the curved surface of the keel. Leeway • Because of leeway, high H pressure builds on the LEEWARD side and keel lift occurs.
- 16. Pull Mode -The Watermelon Seed • When Sail Lift and Keel Combined Lift balance, the boat moves forward Keel Lift Force • Keels takes us upwind and sails take us downwind • We must have flow and Sail Lift balance
- 18. Pull mode isreally FLOW mode.
- 19. So what modeare you sailing in?
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- 23. WIND Close Hauled No Go ZONE Beam Reach Broad Reach Run
- 24. What are the threesources sail power? sail power?
- 25. Angle of Attack Theangle of a sail’s CHORD to the apparent wind.
- 26. WIND WIND WIND 0 45 60 Luffing Proper AoA Stalled
- 27. So what dotelltales show us about AoA?
- 28. Attached Airflow Luff Luff
- 29. Attached Airflow Leech Leech
- 30. Let it out,until it luffs. Often doubt... Rarely in error. Rarely in error. Rarely in error. Rarely in error.
- 31. Draft The AMOUNT ofcamber in a sail and the LOCATION of the deepest point of camber.
- 32. Flat Deep Shape Shape Horizontal Profile: A deeper sail is more powerful but will also generate more drag. A flat sail has less drag, but generates less power in lighter winds. Deeper sails for light air and flatter sails for heavier air.
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- 35. Deep sails forlight air. Flat sails for heavy air. Flat sails for heavy air. Flat sails for heavy air.
- 36. Twist The differencein Angle of Attack from head to foot of a sail. The amount of leeward falloff of a sail’s leech.
- 37. UPWIND TWIST TWIST Note the top batten relative to the boom. Both are showing the CHORD of the mainsail. The top batten is pointing to leeward while the boom is pointing behind the boat.
- 38. DOWNWIND TWIST TwistingOPEN the leech allows the wind to flow freely from leading edge to trailing edge. More twist equals more flow.
- 39. TWIST Wind Speed
- 40. Sail Controls • PrimaryMainsail Controls • Primary Jib/Genoa Controls
- 41. Main Controls Angle of Attack Draft Twist Angle of Chord to Wind Amount and Location Difference in AoA Halyard Sheet Traveler Vang Outhaul Backstay Cunningham
- 42. Jib/Genoa Control Angle of Attack Draft Twist Angle of Chord to Wind Amount and Location Difference in AoA Halyard Sheet Lead Car Blocks Backstay
- 43. Main Controls Angle of Attack Draft Twist Angle of Chord to Wind Amount and Location Difference in AoA Halyard ✔ Sheet ✔ ✔ Traveler ✔ Vang ✔ ✔ Outhaul ✔ Backstay ✔ ✔ Cunningham ✔
- 44. Jib/Genoa Control Angle of Attack Draft Twist Angle of Chord to Wind Amount and Location Difference in AoA Halyard ✔ Sheet ✔ ✔ ✔ Lead Car Blocks ✔ ✔ ✔ Backstay ✔
- 45. BALANCE • How doessail trim affect affect balance? • How does heel affect balance?
- 46. Mainsail Center of Headsail Effort Center of Effort ☢ ✇☢ Combined Center of Effort Center of ✇ Lateral Resistence
- 47. Boat Sails Boat Turns Straight To Port View from astern Boat is heeled Boat is level to starboard
- 48. ☢ ☢ View from astern ✇ ✇ Boat is level Boat is heeled And TURNING and steering straight
- 50. What do wewant? When do we want it? and how do we get it?
- 51. Light Air Days • GIVE ME POWER! • MORE FLOW! • MORE DRAFT! • MORE TWIST!
- 52. Light Air Days No Stall! Eased sheets, boom off AoA centerline. All telltales streaming aft. Not steering close hauled. Ease halyard, outhaul, backstay, Draft cunningham. Move jib lead forward. Open twist to promote flow at top Twist of sail. Jib and main should “match” Leeward heel to promote sail camber. Forward weight to reduce Balance drag. Trim crew weight to helm “feel.” Slight tug.
- 53. Moderate Air Days • No compromises • Max point and speed • Minimum Twist • Design Draft • Design Heel - Flatter is faster
- 54. Moderate Air Days Max trim, slight stall for point. Boom on centerline. Inside jib AoA telltale lifting, top leech telltale slight stall. Draft Moderate depth, starting to flatten Twist No twist for maximum power. Designed heel. Less than 10 Balance degrees. Trim crew weight to helm “feel.” Neutral tug.
- 55. Heavy Air • WHOA!!!!!! • Depower sails • Open AoA for waves • Keep the boat balanced
- 56. Heavy Air Days Traveler down for open AoA. AoA Jib/Genoa eased or even moved outboard Flat, Flat, Flat. Tight halyards and Draft OBC’s Twist Lots of twist to help depower. Reduce heel by moving crew weight Balance to windward. Balance CEs to keep helm pressure to light tug.
- 57. Angle/ Jib Telltale Gear When How Boom Heel Telltale Tales Straight line sailing in Main eased and twisted 1st light air Boom below centerline. Light air with waves All flattening controls Press on the jib so that Whenever you need eased. Wide angle the windward telltale Jib lead forward Gear to accelerate Some leeward heel Inhauler on so mid-leech flows straight. After tacks/motorboat wakes pokes to leeward When sailing in bad air Max headstay sag Mainsheet trimmed so 2nd Flat water in light air Chop in moderate air top batten is parallel to boom Leech telltales flows Moderate angle Inside telltale begins to bounce Gear Nearly flat boat No luff in jib Footing mode 100% Boom on centerline Designed draft Mainsheet trimmed to 3rd Moderate breeze max Flat water Top batten poked to Windward telltale lifts Point Mode windward Max point mode to 45 degrees Gear Heavy air with flat Leech Telltale (on Flat boat Small luff bubble along water main) stalled 50% Jib luff Tight backstay Little headstay sag Tight leech, but active 4th sheet ease to stay in Windward telltale lifts Overpowered control Feathering vertical most of the Moderate air with Top batten flowing Flat as possible time. Gear more waves than wind 100% Especially if you have Front of jib likely Survival Max flattening to bear off for waves luffing Vang hard Boom below center
- 58. More Helm Less helm Move crew forward and to Move crew aft and to Crew position leeward windward Rake the mast farther Mast rake Rake the mast farther aft forward Trim the leech harder and Ease the sheet and induce Mainsheet trim reduce twist twist Angle of heel Heel more to leeward Flatten the boat Make sails fuller; especially Flatten sails; especially the Sail shape the main main Move it down and or Centerboard forward Move it up and or aft.
- 59. Thank you! • Let’s go sailing! • Submit your question cards. • Stay in touch - my pledge to you. • Resources.
- 60. SAIL FAST, SAILSAFE AND STAY IN TOUCH KRISTEN BERRY KRISTEN@JWORLDANNAPOLIS.COM PHONE - 410-599-3542
- 62. Steering With Heeland Crew Weight
- 64. VANG ip tt as m on aft lls Pu Mast bends Main Flattens Tension Main Leech More Vang Boom presses Tension into mast causing lower mast section bending
- 65. Halyard Tensioning Halyard moves Draft forward and slightly opens twist
- 67. Cunningham Less Cunningham Tension More Cunningham Tension Tensioning the cunnigham has the effect of moving the draft of the sail forwards, making for a rounder entry
- 68. Move the sailsdraft forward Draft Draft Forward Draft Draft Aft Draft forward generates less drag and be more forgiving. Draft aft generates more power, but more drag.
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- 70. Pull Mode WIND Beam Reaching 45
- 71. WIND PullMode Broad Reaching 45
- 72. WIND WIND WIND WIND 0 25 45 60 Luffing Pinching/Feathering Proper AoA Stalled
Editor's Notes
- #15 12-06 This slide should change the sail from starboard tack to port tack. Should do transition build in for each of the points - especially showing heeling vectors last.