Protective top cover for your OPTIMIST dinghy. This breathable, waterproof cover is made from Moistureguard 2000 fabric, a quality 900 D polyester with a polyurethane membrane. This breathable, waterproof cover is made from Moistureguard 2000 fabric, a quality 900 D polyester with a polyurethane membrane. You can leave your equipment in the boat. Optimist breathable top cover Optiparts DESCRIPTION Durable cover made of Moistureguard 2000, a heavy duty 900D polyester with a polyurethane membrane which has excellent breathability and is waterresistant. Wide skirts around the edge of the hull for good protection. Fast and easy to install with two adjustable straps.