Intro: sawfish, an unsinkable, lightweight, foam kayak (23 lbs). free diy kayak plans, the hardware store boat. do you really want a kayak? want one so bad you can. I made my first flip 2 years ago using bimini hardware from a paddle boat. i also salvaged some lightweight square tubing from a 10′ x 10′ outdoor pop up canopy that. Using one of these boat plans, you will be able to build the boat you have dreamed of for years. these boat plans come in many variations and there are powerboats.