(Fibre) Reinforced Plastics Option (FRP)

FRP (Fibre Reinforced Plastics), sometimes also called GRP (Glass Fibre Reinforced Plastics) is a technique to design and construct normally rather small vessels by replacing the standard metal plates and profiles (made of steel or aluminium) by laminated plastics. The plates consist of a relatively light and fragile core material that is reinforced by several layers of fibre carpets glued together to form a tensile and endurable coating, normally on both sides of the plates. Originally the carpets were made of glass fibres but an alternative is to use carbon fibres that are lighter and stronger.

There are several important differences compared to standard ships, for example,:

• The thickness of plates is much larger that in a steel ship. This means that if the plate thickness can be neglected in certain cases, it cannot for vessels built in FRP material (for example, in drawings, in calculating volumes, ).

• A consequence is that project settings must be made to consider plate thickness when modelling planar panels and shell profiles.

• Other ships have uniform material qualities whereas densities vary between layers in a FRP sandwich.

• The amount of stiffening is less than in steel or aluminium ships since the FRP plates are very stiff in themselves and the stiffening that is there is of a partly different type.

• Where members of standard ships are fillet welded together FRP members are connected in a different way, for example, by a combination of beads and fibre tissue.

• In an FRP vessel there are fewer parts and not so many small details like notches, clips/collars