At 11:02 02 February 2016, Bruce Hoult wrote:

"Rigging" is a set of devices for adjusting positions, angles, tensions
etc=
of aerodynamic surfaces -- or as a verb the use of such
adjustments.
Origi=
nally from sailing ships but later applied to aircraft (which were
initiall=
y made in very similar ways. The "rigging angle", for example, refers
to
th=
e angle between the chord of the wing and the fuselage.

What we refer to as "rigging" of gliders is merely the use of precision
qui=
ck-release mechanisms that are expressly designed to not alter the
settings=
!
Rigging could be referring to control deflections. These are not
affected by the operation pilots call "rigging" but they can, and do,
change due to wear and to the replacement of parts in the control
linkages. They are adjustable by maintenance personnel. If the
deflections are wrong the glider will not handle as designed and
expected.

Under BGA rules the control deflections on all gliders have to be
checked (and corrected if wrong) at every annual inspection. I expect
other authorities have similar rules.