Question 7

The Correct Answer is C **Explanation for Option C (Correct):** Dacron is a trade name for polyethylene terephthalate (PET), a type of polyester. Like many synthetic polymers, Dacron is susceptible to degradation from **ultraviolet (UV) radiation** found in sunlight. Prolonged exposure to UV light causes a process called **photodegradation**, which breaks down the polymer chains. This leads to a loss of strength, stiffness, and eventual embrittlement of the fabric, severely damaging the sail over time, even when the sail is not actively being used (i.e., stowed outdoors or left exposed on the boom). **Explanation for Incorrect Options:** **A) If washed with soap:** Dacron is chemically inert to mild detergents and soaps commonly used for cleaning sails. Standard washing procedures do not damage the structural integrity of the fabric. **B) When folded frequently:** While extremely rigorous or incorrect folding techniques could cause minor abrasion over decades, normal and frequent folding (flaking) of a Dacron sail is standard operating procedure and does not inherently cause structural damage to the sail material itself. **D) When stowed wet:** Stowing a sail wet is problematic because it encourages the growth of **mildew and mold**, which primarily stain the fabric and damage the stitching. While mold is highly undesirable and weakens the stitching thread (often cotton or nylon, which are more susceptible than the polyester Dacron fabric), the primary source of *material damage* (loss of strength in the main sailcloth) for Dacron, specifically, is UV exposure, making C the most direct cause of structural damage to the Dacron material itself.