1. Sail technology and trim
Nick Turney
North Sails

2. Nick Turney Sail Maker for 10 years Professional Sailor
TP 52
Farr 40
RP 65
Cookson 50
Professional Coach
One Design

3. Sail Technology
Rig Profile
Using measurements from your boat

4. Sail Sizing
We use the rig profile to design sails that best fit the rig

5. Spiral
Edge Curves
Horizontal and vertical curvatures
Broadseaming

6. 3D Layout
Puts a yarn or panel layout on a design surface

7. Flow
Pressure map for the sail plan

8. Membrain
Applies pressure from Flow to rig and sails. Coupled with specified material properties and sail control settings, sails and rig are deformed to match sailing conditions for the specified wind speed

9. Membrain

10. Sail Trim Rig Tune Sail controls Big Lines Small Lines
Vertical shrouds (Uppers/ Cap)
Rake, headstay sag, prebend
Diagonal shrouds (lowers)
Side to side bend
Flatness of main sail
Back Stay
Headstay sag, mainsail shape
Runners/ Checkstays
Big Lines
Sheets
Small Lines
Outhaul
Cunningham
Vang

11. Rig Tuning
1. With your boat on land and your mast up, plumb bob the keel to make sure it is straight up and down
2. Set mast parallel to keel
3. Note that sheerline and chainplates are often inconsistent.

12. RAKE
The fore and aft relation of center of effort to center of resistance creates helm, weather or lee
More rake increases weather helm, less rake decreases it.

13. PreBend Static amount of bend in mast. Affected by: Shroud tension
Upper
Lower
Spreader angle
Mast butt placement
Placement at deck

14. Shroud Tension Increased Tension on uppers, gives
Increased compression on mast---more prebend
Increased forestay tension, to a limit.

15. Rig Tuning

16. Sail Trim
Basic Rule

18. Mainsail Trim
Oversheeting the mainsheet will close the leech, increasing weather helm and making the bow want to point up
Easing the mainsheet opens the leech and decrease weather helm, making the boat easier to sail straight

19. Traveler
The traveler changes power in the mainsail by changing the angle to the wind
The traveler will also affect pointing ability

20. Boom on center line
Adjust to keep helm Neutral
Up in light air
Down in heavy air

21. Cunningham
Draft forward is a better heavy air shape, keeping the leech more open to depower
Draft aft is a better light air shape, firming the leech for power

22. Zero

23. + 25 mm

24. + 50 mm

25. + 100 mm

26. Outhaul Loose outhaul makes the lower main fuller for more power
Tighter outhaul flattens
lower main and opens
leech

27. Tight outhaul

28. 20 mm looser

29. 40 mm looser

30. 60 mm looser

31. 80 mm looser

32. Main Sail Trim Moderate Light Air Outhaul Max Outhaul Loose
Cunningham loose
Vang Snug, no slack
Backstay, adjust power to keep boat flat
Traveler, keep boat flat
Mainsheet top parallel or slightly open
Light Air
Outhaul Loose
Cunningham off
Vang Loose
Backstay, loose
Traveler up to boom on C/L.
Mainsheet- Top Batten
parallel

33. Main Sail Trim Heavy Air Outhaul Max Cunningham, no wrinkles
Vang very firm
Backstay on hard
Traveler, down, below C/L
Mainsheet, top batten open degrees

34. Head Sail Trim Jib Lead Jib Halyard Controls Twist
Forward=more power, less twist
Back= less power, more twist
Jib Halyard
Entry Position
Full Entry is better for chop
Fine Entry is better for flat water

35. Controls Jib Sheet Controls Over all shape and depth
Inboard and Outboard position

36. Head Sail Trim Light Air Medium Air
Medium halyard- finer entry, looser in chop
Lead Forward
Eased Sheet
Medium Air
Tighter Halyard in flat water, looser in chop
Lead Middle
Tighter Sheet

37. Head Sail Trim Heavy Air Really Tight Halyard all the time Lead Aft
Sheet eased

38. Spinnaker Trim
A full shape is more stable and good for power in chop or when pumping
A flatter shape provides more exposed area and is most effective in flat water

39. Spinnaker Trim
Pole too high flattens the luff and moves the draft aft, closing the leech
2. Lowering the pole moves the draft forward and opens the leech

40. Spinnaker Checklist Pole Height, Inboard and Outboard
Sheet Tension Discussion
Pole angle
Keep sheet moving

41. Downwind Trim
Too little vang allows too much twist and flattens the top of the main, depowering the sail
Vang on decreases twist and makes the top of the main deeper and more powerful