You have multiple choices.  CLC sells a rub strip kit (Rubstrip Kit for Kayaks: Protect the Bow & Stern - Dynel Fabric, Graphite Powder & Epoxy (clcboats.com))that may work depending upon how big the area is that you want to protect.  It is basically dynel cloth that you wet out with epoxy then cover with an epoxy/graphite slurry.  Dynel is more abrasion resistant than regulat glass.  I used this on my first five kayaks and found it to be tough but a bit heavy. 

Dynel wet out over glass.

Adding the epoxy/graphite slurry.  Caution, when the epoxy kicks that stuff runs something fierce.  Note all the drips on the cardboard on the floor.

The finished product.

An alternate approach is a product called KeelEazy.  It is not as permanent as the dynel strip but easy to add and easy to remove/replace when needed.  I have found multiple other uses such as protecting my race boats from paddle strikes and also under to prevent wear under my heals.

Here is KeelEazy on my bride's Frej.

Here is KeelEazy on the side of my race boats to protect from paddle strikes.

And hear under the footbrace.

On my Goat Island Skiff, I went with a different approach.  I coated the entire bottom with a VERY expensive but equally tough airboat coating called Wetlander.  So far I am very happy with it.

If go go with either the Wetlander or any kind of additional glass/Dynel layers, you should remove the paint down to epoxy so that you get a good structural bond.