And Macca your right, the quality of the mounting of a non glued beam is in the quality of the way that it is mounted to the deck of the hull. We have always moulded the recess for the beam mountings into the hull mould using the actual beams, and used an internal method of restricting or completely stopping any distortion of the beam at that moulding/mounting point. If this is done well there is no (or only minute) movement/twist at the mounting point. The only twist/flex in between the hulls then is from the twist/flex in the actual beams themselves. This applies equally to whatever material the beams are made from. If you want to see an excellent example of how a beam should be mounted, take a look at the way that the beams are mounted on the marstrom 20