Hi Bernd
I am at home and the workshop is located a few kilometers from my home.
Until the end of January I will work on the Duo 900 to finish the work on the pipes and the central column that goes from the stern tube, through the central tube and forward.
As we agreed, the central beam in 8mm okume 'plywood and holes 185mm in diameter will be built, for the passage of 180mm pipes. It will also be easy to assemble the base of the mast, since there will be a counter plate underneath with 4 240mm bolts, the one below will have a 60mm x 600mm tube, with a stainless steel cable attachment for the weight of the mast.
As per drawing it will look like this.
Bye