The two preceding tests were hull models in scale 1:10. They were aimed at finding the most optimal hull shape for sailing shallow waters without compromising sea abilities to much.
This test is too make a sculler/canoe/kayak with the planned hull form in scale 1:5 This allows for actually sit in it and get the full feeling of the hull performance.
The Rockboat principle is to laminate the hull with "bricks" of Rockwool to clad on the inner walls of the hull. The bricks are cut to form the outer shape of the hull. The outer surface can be covered with a skin for the desired purpose. For this build I plan to use glass fibre in my own secret blend of acrylic rubber concrete to make a semi hard surface, as I also keep it lightweight by not making it too thick and strong.
I think 5-7 cm spray concrete skin will be better for the full scale product. After all it is meant to possibly have to withstand ice and driftwood during its full life expectancy.
Here I have chosen 4mm sub-roof mdf plates. For the inner skin of the hull. They are water resistant, light and strong. To keep it stable under the construction I build them on a jig of cheap wood materials.
This is how it looks after the first day of work.
The inner hull will have a very box formed shape. The outer hull shape will be created as I work with the "bricks" I cut from Rockwool.
Probably the best way to build a concrete boat