>>Back to headlines<<

Within GTT's technologies, the unassuming yet crucial role of birch plywood takes centre stage, echoing a history that traces back to the earliest maritime construction. This indispensable material, sourced from renowned European suppliers like UPM, Metsä Wood and Latvijas Finieris forms the backbone of vessels fitted with GTT 's technology.

In order to enlarge the sources of birch plywood supply, GTT is introducing a new, more flexible, method of acceptance of inclusions on the plywood faces, all the while ensuring that the overall performance of the material remains uncompromised. During the intricate process of birch plywood production, a critical initial step involves meticulously peeling the trunk tree to obtain plies. These plies undergo a sorting process based on factors such as size, quantity, and the type of inherent inclusions arising from both the wood and the manufacturing process. These inclusions may include holes, knots, splits, patches and more.

The hierarchy of ply usage is dictated by inclusion severity. Plies bearing the most inclusions find their place in the inner layers, while those showcasing the best appearance are reserved for the outer faces. This meticulous selection process contributes not only to the vessel's aesthetic appeal but also to its functional qualities.
Noteworthy is the grading system employed: the plywood used for Mark III technology meets BB quality standards, while the plywood used for NO96 and Super+ technologies meets WG quality standards. Despite its higher incidence of inclusions compared to BB-grade, WG-grade plywood still meet the stringent requirements of these advanced GTT technologies. 

Yet, to ensure the resilience of these plywood materials, extensive mechanical bending and tensile tests have been conducted on specimens with varying degrees of inclusions. These tests, spanning a multitude of samples, underscore the unwavering commitment to quality and safety inherent in GTT technologies.

The study clearly demonstrates that increasing inclusions on the external plies of plywood has no noticeable impact on the overall performance of the product. These promising results have paved the way for a practical optimization while maintaining a high level of quality.

Furthermore, the material specification dedicated to the plywood used in Mark III technologies has recently undergone a significant revision. Marked as “nb 04”, this revised Mark III version has received approval from the main classification societies, including the American Bureau of Shipping (ABS), Bureau Veritas (BV), Lloyd's Register (LR), and Det Norske Veritas (DNV). This collective endorsement from renowned classification bodies emphasizes the adherence to the highest industry standards and validates the use of plywood with an increased tolerance for inclusions.

This adjustment provides shipyards with added flexibility in sourcing birch plywood. It signifies a nuanced approach that strikes a balance between operational efficiency and technical standards, reflecting the industry's commitment to pragmatic solutions in the face of challenges. This shift in specifications positions the maritime industry at the forefront of adaptability, ensuring a steady course forward with GTT technologies.


>>Back to headlines<<