What did Indians use to protect canoes from water?

Answer 1

Since canoes were always of wood they did not need to be protected from water (wood floats all by itself). In the eastern regions birch or elm bark was used, or logs were hollowed to make dugouts.

The stitched seams between sheets of bark would be sealed with a mixture of charcoal and pine pitch (the sticky sap of pine trees), which hardens to form waterproof joints. This also gives a pleasing contrast between the pale bark and the dark brown seams.