[Ed in Maine]

A few weeks ago some of you sent me an article on how to build your own trunk. I did get started and have made the bottom and sides. I am having trouble making the curved top. The plywood I used cracked when bent. The article specifies (2) layers of 1/8 material that is soaked in water and then bent around a form. My question is has anyone found a source for 1/8 in. marine plywood or other material that was good for this application? Thanks for your help, Ed