Pretty much any paint will seal the weave of any fabric. Some paints dry hard and may crack a little so that is why it is best to use a coating that has some flex ( satins are better than glosses ). Kayak skins do not have much flex as long as the fabric is stretched tight.

Some coatings are fairly thick and provide a layer of protection in themselves, , these are the expensive ones that are the two part coatings.

Or you can buy the cheapest polyurethane ($7.00 qt) and mix in some powdered pigments and still have a good skin.

In my experience it is not punctures that you have to worry about so much but abrasion from launchings and landings. Barnacles are Hell!