hide glues are really a form of gellitan. In small batches knox granules work well. The urine is just a form of amonia to break down the fats that would prevent the skins from smoke curing. In AK there are still a few walrus skinned boats to be used, very flexible with sinue sewn strips and steamed bent wood braces. These boats are so much quieter than the plastic and fiberglass boats that I have used.