sailboat seamanship 187
Halyards. Set halyard tension until you just start to get a slight (but
not deep) single vertical crease building along the luff. Stop tensioning at
that point and cleat off your halyard. As wind increases, wrinkles—called
scallops or crow’s feet—may develop along the luff. Tension the halyard
just enough to remove the wrinkles. Th is fl attens the sail and also
counteracts the tendency of a strengthening breeze to move the draft
position aft.
Cunningham. A fabulous invention from the racing world, this simple
device tensions the mainsail luff without using a halyard. It’s a large ring
installed about 8 to 10 inches above the mainsail tack. Run a line from the
mast base up through the ring and back down to a cleat on the opposite
side. Haul on the line to tension the luff. Larger boats should rig a small
block and tackle. Adding luff tension with the halyard is oft en diffi cult
or impossible when the mainsail is full of wind; it’s a lot easier with a
cunningham. Again, greater luff tension means a fl atter sail with a more
forward position of maximum draft , both of which are desirable in a
strong breeze.- Mainsail leech control system. Th e leech is oft en the forgotten edge of
sail trim, yet it plays a vital roll in proper draft control. Use the mainsheet,
boom vang, and traveler to control the mainsail leech.
Mainsheet. Just 60 feet above the water’s surface, the apparent
wind is up to 50% stronger than it is at sea level, and the apparent wind
direction may therefore be 10 to 15 degrees farther aft than it is at deck
level. We need to shape the upper half of each sail to this different
apparent wind. To do this, we introduce twist into the top of the leech
by easing the mainsheet. Before making this adjustment, sight up the
mainsail leech. Is it cupped to windward along its entire length? If so,
the sheet is too tight. Ease the mainsheet to put twist into the top half of
the sail as follows:
Light air. In light-air conditions of less than 6 knots, take care not to
cup the leech. You need an “open” leech to keep that light and tenuous
airfl ow moving across the mainsail and exiting without turbulence off
the leech. Ease the mainsheet just until the uppermost batten opens
slightly to leeward (i.e., until it is cocked slightly to leeward of the
boom).
Moderate wind. In a moderate breeze of 6 to 12 knots, adjust the
mainsheet so that the uppermost mainsail batten lines up parallel with
the boom.
Heavy breeze. In heavier winds, use more twist. You want to spill some
of that high-octane wind to reduce heeling and balance the boat for
a light helm. Ease the mainsheet several inches. Th en use the traveler