Fagerdala Hull System
Tanker Applications

The concept of the Tanker Hull System is to clean the existing steel surface, apply glue and a thick layer of structural foam to a typical single hull vessel. An impact resistant layer of high strength steel plate will then be glued and welded on top of the foam. A system, which in addition to strength, gives excellent corrosion protection to the original hull steel plating. Preferably, the foam layer should be thick enough and cover a large enough area to give buoyancy comparable to or exceeding the lightweight of the hull.

One of the basics of the Tanker Hull System is to avoid penetration of the outer skin as far as possible. The combination of high strength steel and a relatively thick foam layer is designed to spread the load and make the inner hull deform as a damage zone before the outer skin is penetrated. When the foam compresses and the inner hull deforms, a large amount of energy is absorbed. This interaction between inner hull, foam and outer skin is the reversed way of thinking compared to conventional double hull designs. Normally the outer skin is quite easily penetrated and the objective is to never reach and penetrate the inner skin.

The Tanker Hull System is based on the Swedish patent (#0302765-3 and #0302933-7) originated by Sven Jönsson. The patent describes a way to improve a hull by gluing sheets of foam material to a hull and on the foam apply a hard shell. The combination of foam and a hard shell has many advantages. Old and corroded hulls can easily be renovated, concurrently good thermal insulation and sound insulation is achieved. The foam also has an ability to absorb energy. The sandwich effect contributes with greatly improved panel stiffness and, in some cases, increased global hull stiffness.

The reason for the invention is to develop a hull system that will reduce the risk for leakage due to accidents. It will improve properties such as damage resistance, acoustic damping, thermal insulation, corrosion, stability, stiffness and net lift. This is accomplished with the invention by designing the hull as a sandwich, i.e. a thick layer of foam glued to an inner metal hull and coated with a hard surface.

Technical report: Parametric study and collision analysis »

GL, Germanischer Lloyd, has issued a Type approval for Fagerdala Marine System AB of: Visco-elastic bonding of fibre reinforced sandwich on metal structures. See GL approval (PDF) »