For our pontoon cover, we chose to use Sur Last ® Fabric. Sur Last is a solution-dyed polyester with a urethane coating on the underside to increase water and mildew resistance and to add stability. Sur Last is a great cover choice for boats in the Midwest or other more temperate climates. If you live in the tropics, where the sun is stronger, you might want to use a Sunbrella ® Marine Grade fabric, which will offer even better UV resistance. more