Cellular tendon design expands the envelope of water depth and payload on TLPs and enables their use for ultra-deepwater developments as well as production hubs. Cellular tendon design was initially introduced to the industry at OTC Brazil 2013 where its design elements and features along with the corresponding feasibility assessments were presented. For the initial development of the Cellular Tendons, the fabrication and installation were based on onshore assembly and tow-out of the full-length tendons to the installation site. This design was developed mainly for installation sites where a nearby fabrication yard with open water access is available. This design is especially suitable for developments in areas with local content requirements, where a significant amount of investment can be made in local yards for fabrication and assembly of the tendons.

In order to accommodate current standard industry practice for fabrication and installation of the tendons, an alternative design to the full-length cellular tendon has been developed. This alternative design, named the Hybrid Cellular Tendon, employs the same tendon transportation and installation methods as for the conventional tendons. The hybrid cellular tendon can be fabricated in any of the existing tendon fabrication yards and can be installed by any of the current tendon installation vessels.

This paper presents design of the general system and component of the Hybrid Cellular Tendon. The paper demonstrates that performance of the Hybrid Cellular Tendon satisfies the ultra-deep water TLP requirements while providing advantages over that of the conventional tendons for TLPs as hubs with large payloads. The construction and installation of the Hybrid Cellular Tendon, which are well within the current industry's capability and practices, are discussed as part of the design in the paper. The Hybrid Cellular Tendon design further proves the feasibility of cellular tendons in enabling TLP applications in ultra-deep waters and /or with large payloads.

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