2tugboats.com tug boat plans free pictures and ideas. plus, a free sample pdf for the keel for building your own 65. Composite cruiser – the primary purpose of this design was to build a small pram style boat that was ultra-lightweight, easy and inexpensive to build, was unsinkable. Building a grp boat from scratch! – the rock’n’rolla way my-self and gary began thinking of building a boat between us about ten years ago. i drew some ideas of a.