CS36T Owner’s Manual
Page 9
4
RIGGING
4.1
General
It is important to understand the principles involved in order to do an effective job of mast tuning.
Standing rigging refers to fixed lengths of stainless-steel wire or rod supporting the mast. If they offer
fore and aft support, they are called forestay and backstay. If the support is principally transverse, they
are called shrouds.
4.2
Spars
The mast on your CS .36 is supported by three sets of shrouds. Those running from the masthead to
deck are known as upper or cap shrouds.
Intermediate shrouds, fixed at the inner end of the upper shrouds, run through the tip of the lower
spreaders to the chain plates.
Two sets of lower shrouds are fitted, known as forward and aft lowers. Lower shrouds, led to chain
plates forward and aft of the mast centerline, provide some fore and aft support.
To reduce the large tensile forces in the shrouds and compressive load in the mast, the upper and
intermediate shrouds are led over spreaders. The upper spreaders lead the shrouds out from the mast
and provide a deflection of approximately 12°, which is considered ideal. However, the shrouds impart a
side load, acting horizontally along the spreader. The intermediates take some of this load off the mast
at the upper spreader, while the lower shrouds do the same at the lower spreader.
It is obvious that the more standing rigging that is used transversely and longitudinally, the stiffer the rig
will be, allowing a smaller mast section, thus reducing windage.
However, the French-made Isomat spars used by CS, together with the standing rigging described above
provide a very good balance of strength and simplicity.
4.3
Tuning
Tuning involves adjusting the tension of shrouds and stays so that the mast will remain straight under
various sailing conditions and when moored.
Tuning involves two phases: (a) Tuning at the dock or while moored; (b) Fine tuning while sailing.
