1. Sail Trim and Shape
Nick Turney

2. Topics to be covered Different Types of Sails Sail Trim/Controls
Downwind Sails

3. GOAL #1 – Boat Speed- Cruising or Racing, we all like to go fast!
How is it achieved – BALANCE!
No Helm
Sail Set Up
Sail Trim
Selecting the proper sail for the conditions

4. Different Types of Sails
Cruising
Racing
Club Sails
Heavy Boats vs. Lighter Boats

5. DIFFERENT SAILS FOR DIFFERENT BOATS
Some boats are very fast and easily driven and sail with very straight exits on the sails as a result.

6. Some boats are larger and require a more powerful sail plan and set up
Some are heavy, sluggish and need rounder, more powerful sails.
Some boats are larger and require a more powerful sail plan and set up

7. Different boats and sail plans demand different sail shapes- the J/24 sails best with a draft forward straight exit design but sheeted very hard

8. The Thistle sails fastest with draft aft round exit shape mainsail.

9. Some jibs setup on straight forestays with little sag.

10. Some sail with a great deal of sag, such as this Kevlar laminated T ten jib.

11. No matter what type of boat or sails you have you always have the ability to change the sails shape and set up

12. Mainsail Trim

13. Mainsail controls Main Sheet Halyard Traveler Cunningham Outhaul Vang
Backstay

14. Main Sheet What does the Main Sheet do? Controls Leech Tension
Pointing Ability
Overall Power of The Sail

15. Mainsail Trim
The upper telltale is an excellent indication of mainsail twist
When the telltale stalls the mainsail is overtrimmed, when it flows the mainsheet tension is correct

16. Basic Rule - Mainsail upwind

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. Mainsail Trim
The mainsail is over trimmed when the telltale curls to leeward
Slight over trim on the main puts the boat into point mode

20. Main Halyard What does it do? Entry angle Draft position
Loose halyard= draft aft
Tight halyard= draft foward

21. Main Halyard
NO BUMPS

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

23. Traveler Adjust to keep help neutral Up in light air
Down as the breeze builds

24. 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

25. J/24 mainsail - 10 knots true wind speed

26. camber
16.7%
16.2%
13.1%
draft
47.4%
42.8%
42.4%

27. camber
16.4%
15.8%
12.5%
draft
46.1%
41.2%
37.7%

28. camber
15.6%
14.7%
11.5%
draft
42.0%
37.8%
35.7%

29. camber
13.9%
13.0%
10.1%
draft
36.2%
34.6%
35.9%

31. Controls shape in lower aft part of main
Outhaul
Controls shape in lower aft part of main

32. Outhaul
A loose outhaul makes the bottom of the main fuller for more power
A tight outhaul flattens the bottom of the sail and opens the lower leech

33. tight outhaul
10 mph
camber
8.4%
9.5%
6.0%
mainsheet length constant

34. 20mm looser outhaul camber 9.1% 10.3% 6.8% 10 mph
mainsheet length constant

35. 40mm looser outhaul camber 9.5% 10.8% 7.4% 10 mph
mainsheet length constant

36. 60mm looser outhaul camber 10.0% 11.4% 8.2% 10 mph
mainsheet length constant

37. 80mm looser outhaul camber 10.2% 11.9% 9.1% 10 mph
mainsheet length constant

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

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

40. Headsail Trim

41. Headsail Trim
Low aspect headsails sheet at an angle nearly bisecting the leech and foot
High aspect sails sheet more directly up the leech
Moving the lead forward will close the leech for power, moving it aft will open the leech to depower

42. Headsail Trim
Proper trim allows the wind to flow evenly on both sides of the sail, telltales flow aft
Overtrimming stalls the windflow on the backside of the sail, creating vortices that spin the telltale

43. Set sail same distance off spreader and base

44. J22 Jib Good Set Up

45. J22 Jib too tight

46. Headstay Sag
1. Headstay sag increases depth in the headsail to add power
2. Sag can be controlled through backstay and shroud tension
3. Sag controls sail entry, deep for chop, fine for flat water

47. Sail depth is controlled by headstay tension or mastbend.
Flatter
Fuller

49. Match Profiles

50. Spinnaker Trim

51. 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

52. Spinnaker Trim
A high pole flattens out the top of the spinnaker and depowers the leeches
A lower pole stabilizes the spinnaker and makes it easier to fly
As a rule the clews should be equal height

53. 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

54. Notice the different shapes due to the different pole heights…
These are the same design of spinnaker!!

55. Spinnaker Trim
As a rule, the spinnaker pole should be square to the wind
Over squaring the pole means oversheeting the spinnaker

56. Spinnaker Trim
Lead forward tightens the leech and powers the foot with increased depth
2. Lead aft opens the leech and flattens the foot

57. Asymetric

58. Asymetric Tack line controls the luff tension and shape
Looser tack- rounder luff
Tighter luff= less power

59. 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