PAGE 24 • WINTER 2005 THE JOURNAL OF THE AMERICAN SAILING ASSOCIATION
INSTRUCTOR TIP
By Capt. Paul Miller, California Sailing Academy
Key Tips for Optimizing Jib Power
Part 2 of a 4-part series on proper sail trim and shape
A
s with the mainsail, the primary considerations in
be moved forward, and by easing them, the draft will
controlling jib power are sail trim, shape and twist.
move aft. With horizontal stripes on a sail, the shape is
When the true winds are light, it is best to power
easier to evaluate from the deck.
up the headsails by making them fuller. Stronger true
winds favor flattening them so as to power them down. Sail twist and differing wind speeds
By moving the jib fairlead fore and aft, twist may be
Shaping the jib can be achieved by adjustment of the
reduced or added to the sail. The twist in the jib and
halyard tension, jib downhaul if available, and
main should be similar.
adjustment of the jib fairlead to obtain the proper twist.
By tightening the jib halyard or downhaul, the draft may
At the top of the mast, the true wind velocity is greater
and the apparent wind is more in line with the true wind.
Lower on the mast,
the true wind is less
and the apparent
wind is from more
forward.
Thus, the sails should
have a slight
decrease in twist
from top to bottom.
By placing telltales
Example of a Jib Halyard with
on the sails from top
Jib Draft moved aft by
too much tension for existing
to bottom, it is
lessening jib halyard tension.
wind conditions. Note how far
relatively easy to
Note that the sail curve / draft
forward the sail curve / draft is to
is further back now from the
adjust the jib fairlead
the sail’s leading edge.
sail’s luff.
until all the telltales
flow horizontally
along the entire
height of the sail.
R
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