Different float designs are presented and the investigations are discussed.

One of the important factors in seaplane design is the stability at rest on the water. Ordinarily this is secuted by basing a new design on the proportions followed in some old and successful design. Sufficient data has been compiled from various sources to clear up this point in each of the cases requiring study. These cases are lateral and longitudinal stability of twin floats, longitudinal stability of single floats, and lateral stability where wing tip floats are used (as with a single main float or boat hull). The longitudinal stability of boat hulls is so great that it may be neglected. The method followed in the case of single and twin engine floats is to obtain a satisfactory approximation to the metacentric height and study the values actually used in successful designs.

This part of the report presents characteristics and graphic representations of water resistance. The laws of similarity are discussed as well as the theory of model tests. The test procedures and model tests of other countries are also discussed.