Naval architects MINUET Y CALABRESE, entrusted us with the finite element structural calculation of a 52 'motorized catamaran. For this work several records were studied, ISO, Bureau Veritas, ABS, RINA. Finally, it was decided to go ahead with the registration RINA (Italian Navale Registry). Several cases of loading were studied and local lamination and reinforcements were obtained to make the boat as light as possible but at the same time very resistant and reliable. The deflections of the large decks of this modern Catamaran were studied. Several reinforcements were designed with unidirectional fibers following the direction of the stresses. The construction of the same is being done in infusion.