QUICK ANSWER: HOW ENCLOSURES AFFECT SAFETY A quality custom enclosure improves on-water safety in two ways. It preserves clear sightlines from the helm, and it protects the operator and crew from wind, spray, and UV. The essentials: Bonded impact modified acrylic panels transmit 91% of visible light (ASTM D1003), block 98% of broad-spectrum UV, and won't yellow (Yellow Index 0.5, ASTM D1925) Soft isinglass panels roll up for open-air running but haze and yellow within 5 to 7