Abstract: Systems and methods for adding buoyancy to an object are described herein. A buoyant material may be enclosed inside a flexible container, heated, and inserted into a free flooded cavity inside the object. The flexible container may then be formed to the shape of the cavity. After the flexible container is formed to the shape of the cavity, the flexible container may be cooled. The flexible container may hold a pre-determined amount of the syntactic material that provides a fixed amount of buoyancy. According to another aspect, systems and methods for packing a vehicle are described herein. In some embodiments, a buoyant material may be molded into the shape of a hull of a vehicle, and a plurality of cutouts may be extracted from the buoyant material which are specifically designed to incorporate one or more instruments.