ROOT CHORD- The chord length of a fin at its base.
S
S-GLASS-Magnesia/alumina/silicate glass reinforcement designed to provide very high tensile strength. Commonly used in high-performance parts.

SANDWICH STRUCTURE-Composite composed of lightweight core material to which two laminate skins are adhered.

SECONDARY BONDING-the joining together, of two or more cured composite parts.

SECTION-A cross section cut along a chord line.

SECTIONAL DRAG- These values can be obtained from compiled data such as "THE THEORY OF WING SECTIONS", Dover Publications-see VISCOUS DRAG

SHEAR- An action or stress resulting from applied forces that causes or tends to cause two contiguous parts of a body to slide relative to each other.

SPAN- the submerged depth of a fin.

SPIN OUT- A condition where the lift generated by the fin is no longer able to counteract the side pressure exerted by the sailor.

STALL-A condition where the  angle of attack of a foil is increased past the foils ability to maintain laminar flow. This applies to foils (wings) in the air and foils (fins) under the water.
STRESS CRACK-External or internal cracks in a composite caused by tensile stresses.

SURFACING VEIL-A light weight fabric (usually non-woven) used to enhance the quality of the surface finish. Designed to block out the fiber pattern of underlying reinforcements.
T
TACK-Stickiness of an uncured prepreg, or a partially cured layup.

TAPE-thin strips of reinforcement available in both unidirectional and woven styles. Sometimes prepreged.

TENSILE STRENGTH- Maximum stress sustained by a composite specimen before it fails in a tension test.

TIP- The part of the fin furthest from the board.

TOW-An untwisted bundle of continuous filaments, designated by a number followed by 'K'. The