Mainsail Trim

1
Mainsail Trim

• Trim the front of the Jib and the back of the
  main
• Trim cycle
• 1) Twist
• 2) Depth
• 3) Draft position
• 4) Helm balance

2
Leech Tension (1)

• Controlled by Mainsheet
• Trim mainsheet until top batten is parallel to
  the boom.
• Increased mainsheet tension moves the leech to
  windward.
• Tighter leech moves the draft aft and increases
  weather helm

3
Depth (2)
Loose outhaul

• Use mast bend and outhaul to control depth.
• Mast bend affects the upper 2/3s of the sail and
  moves draft aft
• Outhaul affects the lower 1/3
• Outhaul tension opens the slot lower down and
  opens the leech

4
Draft Position (3)

• Controlled by the Cunningham
• Cunningham tension moves draft forward and opens
  the leech

5
Helm Balance (4)

• Trim the main position until top telltale flow
  most of the time
• Control heel and reduce helm by dropping the
  traveler to leeward
• Keep the leeward rail out of the water using the
  traveler first then adjust main power for wind
  conditions

6
Traveler Main sheet interaction

• On a stock I-36 moving the traveler to leeward
  causes increased mainsheet tension

7
The Slot

• Set both main and genoa to have even slot top to
  bottom
• Reaching twist the main to match genoa twist

8
Downwind

• When running the main is stalled
• Maximize projected sail area
• Keep leech from falling off by reducing twist
• Heel the boat to windward if you can

9
Questions