I got a catalogue in the mail that sells a product for making "permanent repairs on tarps,tents,awnings and more".
An aggressive adhesive that adheres to any surface,even a damp one, to create a waterproof seal over tears and puncture-tested and proven repeatedly in open-water gales.Keeps holes from reopening and growing bigger too.
The transparent tape is lightweight,flexible and won't crack in cold weather.
3"x15' roll is $15.00
Sold by Duluth Trading Post
800-505-8888
Winchester 88