MRHELLO, If you go back to the beginning of this topic I explaine how I made the island, It's not the best way to make an island but I used materials I already had.
If I were to build another one I would use 4" corrugated plastic pipe, then bend it to the shape you want and add pvc crossmembers to hold the shape, then fill the 4" pipe with expanding foam, after that put your screening on with zip ties.
The 4" pipe will give you more flotation without the degradation of exposed foam. Good Luck
