Technology

CSUBs 20+ years of GRP deliveries has shown that key aspects as installation cost, soil issues, lead times, environmental impact and galvanic corrosion all benefit from choosing GRP composite technology.

Glass-fibre Reinforced Polyester

GRP (Glass-fibre Reinforced Polymer) was introduced in the late 1940’s and were adopted in the 50’s and 60’s for a wide range of applications. The high strength-to-weight ratio and corrosion resistance, combined with superior ductility, proved to be valuable. This is especially proven in yacht building, where builds from the 60’s and 70’s are still in use with only cosmetic maintenance. In addition, current state-of-the-art GRP laminates have seen significant improvement from their predecessors over a broad range of factors.

The uses for GRP have since broadened to the extent that it has now become common in our surroundings. Examples would be construction of small crafts (land and sea), underground water and fuel tanks, maintenance-free exterior panels for buildings, various civil piping etc.

Since delivering the first GRP subsea protection covers in 1994, client feedback has reflected significant savings in installation and service using GRP composite, without the penalty of manufacturing cost. Client has also highlighted cost savings due to the reduced need for planning as a result to the reduced lead times obtained by the use of GRP technology compared to equivalent steel alternatives.


As demands for reducing energy consumption are increasing, weight savings are becoming equally essential. Composite provides the perfect solution by being lightweight combined with design flexibility and increased structural integrity compared to more traditional steel solutions. The use of composite in other industries, such as aeronautic-, automotive- and marine vessel producers, is increasingly being implemented. Furthermore, due to the production method and lightweight materials, composite structures in general show a smaller environment impact over the product life cycle than its conventional equivalents.

Technology - CSUB AS

Vacuum infusion

CSUB main fabrication technique is Vacuum Infusion. Vacuum Infusion is a process that uses vacuum to infuse resin into a laminate. Dry fiber mats are laid onto a mould and the vacuum is applied before resin is introduced. Once a complete vacuum is achieved, resin is sucked into the laminate via carefully placed tubing. After the fiber is saturated with resin, the laminate remains on the mould for curing. The process gives a high quality laminate with excellent and consistent mechanical properties.Compared to open moulding the main benefits are :

  • Reduced emission of gas to outer and inner environment
  • Cleaner and more worker friendly environment
  • Higher quality of laminate with less voids
  • Increased strength/weight ration
  • Minimal voids eliminates water ingress in deep water/high pressure

CSUB has since 2003 developed this technique specially aimed for optimizing injection of large parts. We have further developed our technique to be able to perform injection also with integrated foam stiffeners. This will reduce the requirement for secondary bonding operations.

Vacuum infusion - CSUB AS

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