190 seamanship secrets
How to Shape Headsails for Power or Speed
Unlike a mainsail, a headsail has only one supported edge. But like the main,
we need to make every effort to keep draft properly located.
Headsail luff control system. Control the draft of a headsail with halyard
tension. Headsail draft should stay between 35% to 45% aft of the luff. Use
the table below as a rough guide for setting headsail draft.
Q 35% (breezy to heavy winds)
Q 40% (light to moderate winds)
Q 45% (very light winds; “ghosting”)
Headsail leech and foot control. All headsail leech and foot trim needs to
start from a “neutral” sheet-block position along the track. Use these three steps
to fi nd and mark the neutral position.
- Mark the middle of the headsail luff with tape. On boats with roller furling,
estimate by eye the center point of the luff. We’ll refer to this point as your
headsail’s mid-luff point.
Th e draft of a headsail is controlled for speed and power.