My son-in-law works for a supplier of various industrial materials. I asked if there is something better than duct tape. He said very much, check out 3M Extreme Sealing Tape 4412N that it is used for RV roof repairs. I found this web site should you be interested: 3M Extreme Sealing Tape - 3M US Maybe carry a small roll to use in an emergency for a cracked sky...