A stress analysis has been carried out for the 12 meter yacht "Azzurra", the Italian Challenger to the America's Cup 1983. Two different structural arrangements have been investigated. One is the existing transverse-framed, and the other is a study in which both longitudinal and transverse stiffeners have been included.
The structural models have been analyzed with two different calculation systems under the same loads. The first method is a classical naval architecture direct calculation, while the second is a Finite Elements Method analysis.
A measurement sea trial to evaluate the stresses in various points of the yacht structure has also been performed on "Azzurra" to obtain a feed-back able to check the results given by the numerical analysis.
Some comments and conclusions on the behaviour of the two types of structure are presented.