Apple pie tender-day by day record of building chuck merrell’s apple pie pram as a tender for my tanzer 22 boat. video link of launch.-estimate for building a. A few months ago brian contacted me, asking a few questions regarding the capacity of my coroplast boat designs. i tend to be over cautious when specifying maximum. There are many designs and plans for building boats from one sheet of plywood. here are some designs and links to free one sheet boat plans.