i found a good sand texture on google, and slighty altered it so that the edges matched, i did this by using photoshop, using the stamp tool, i lowers the opacity to 50% and did the top and bottom, and then side to side, this minimized the square box effect when applying as a material.

for the time being i added a large blue plane to act as the sea to give me a good idea of the height of the pier from the surface of the sea.