Hope I can get some advice. The 17 footer in the picture is being refitted with a balanced lug rig. Please ignore the frame to keep the canvas cover from holding water. I plan to insert a sturdy bulkhead against which will be mounted the mast partner (approx where the front seat is) and to deck the area between it and the bow. I also propose to do something similar at the stern which will strengthen this section and allow additional storage, buoyancy and somewhere to put the massive 2.5hp mercury.

When sailing I imagine that between my new 5m mast and my 90kg bulk possibly sitting on the rail, a fairly substantial torsional stress will occur. Do you think the existing frame as it is will cope? Do I need to add some framing to resist this stress? Am I over thinking this

Thanks