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Abstract Cast node is an iron alloy with low carbon content, often mixed with other chemical elements e.g. silicon, manganese, sulphur, phosphorus, etc. It is produced by pouring the molten steel into molds with any complex shapes. Cast node was successfully used at the main leg interface from the 32,000MT floater module to the hull in a complex deep-water offshore structure. It was chosen against the normal traditional leg because these cast steel nodes offer better strength and fatigue life, as they can be customized to match load requirements. Additionally, their use simplified fabrication, resulting in improved schedule efficiency and cost savings. The cast steel fabrication strictly adhered to NORSOK standards, using 150 mm thick cast nodes in this application. Manufacturing was carefully controlled to meet all requirements in the codes. Finite element analysis, employing solid elements, was used for strength and fatigue assessments. Spectral fatigue analysis evaluated wave-induced damage, while deterministic analysis based on acceleration histograms assessed low-frequency damage. Both results were combined to determine overall damage. Additionally, misalignment was incorporated into the design to account for variations in the as-built cast nodes, providing contingency. The integration of cast nodes into the heavy floater production unit was successfully implemented. Four cast columns were used to directly transfer the high load from the 32,000MT module to the hull, with their custom geometry ensuring satisfactory fatigue life. This approach simplified the construction and fabrication processes by reducing the number of components, thereby enhancing the overall schedule. Additionally, for float-over operations, the four-column load transfer interface minimized the risk of unbalanced loads, contributing to a safer and more efficient procedure. Overall, the use of cast nodes improved structural performance, streamlined fabrication, and supported the successful execution of the float-over, demonstrating the effectiveness of this design solution. The use of cast steel effectively addresses the complexities of designing, fabricating, and installing heavy deep-water structures. Its customizable size allows for molding to meet specific fatigue life requirements, while its tailored design can accommodate heavy loads, resulting in weight savings. This approach was successfully implemented in the Heavy Floater Production Unit, which has a combined weight of 64,000 MT.