It has been a solution looking for a problem since the 1930's.... It has high windage making docking a nightmare... I can only speculate what will happen with such a hull configuration in 60 knot gusts and 30 foot waves... For the claimed stability in five foot waves it needs to have relatively narrow deep draft submerged hulls... Like a submarine, controlling bouyancy will be critical with even a few pounds of change causing noticeable sinking or rising.. Longitudinal CG changes will cause porpoising... Putting the superstucture on mechanical lifts is a cost and weight and maintenance nightmare... It really is a technology that will work only for specialized needs such as military... Like Moeller's Skycar, it is likely to be around for many years, sucking up money from gullible dreamers... denny / k8do ********************