The peel-off backing ripstop tape works well for small patches. Round the corners of the patch and then put a bead of Aquaseal around the edges and over the hole itself on the inside behind the patch. You can usually get packages of the tape at camping good stores (Coghlans is one brand) or sewing departments.
I even used a strip of ripstop peel and stick tape to patch a badly gouged and leaking fiberglass canoe keel after a run in with a rock many years ago. We filled the gash with chewing gum and smoothed the tape over the outside of the hull to hold the gum in the hole, praying this "temporay fix" would at least get us back to the shuttle. Worked so well that the canoe owner paddled it for a couple of years with that dayglo orange tape and Juicy Fruit repair intact on it.
I have carried a package of the stuff with me ever since that event and patched many an item with it.
URCHIN Portable Anchor
Deck Rigging Gear