Numéro : 2808 - Year : 2024
Repairing lngc side shell post-impact: an innovative class-approved solution for afloat hull reinforcement pending next shutdown
Jean-Philippe COURT, Marie-Odette QUEMERE, Julien BEC, COLD PAD – Paris (France)
Given the current global circumstances, both Liquified Natural Gas (LNG) shipowners and operators are striving to enhance fleet performance and ensure optimal service delivery to clients. In pursuit of these goals, they are exploring innovative solutions to minimize vessel downtime, including afloat repair methodologies such as hull structural repairs. Damage to the hull structure often results in Class condition issues, necessitating to stop the commercial activities, decommissioning the vessel for crop and renew operations. While these operations are routine, they can lead to vessel deviations, gas freeing from tanks impacting air emissions, and missed commercial opportunities and turnover.
This paper outlines how Gazocean (ship manager), France LNG shipping (Shipowner), Cold Pad (technology provider), and Bureau Veritas (Classification Society) collaborated to develop an innovative afloat repair strategy for an LNG carrier submitted to collision with a tugboat that caused Class condition issues because of two dented hull panels on the side shell. This original structural repair, combined with non-intrusive carrosserie works techniques that could be performed from inside the vessel, allows avoiding an unplanned repair period of approximately eight days for the shipowner and prevents loss of trading opportunities for the charterer.
The paper details the technology involved, leveraging bonded hull repair techniques originally developed for FPSO (floating production storage and offloading platforms) and approved for marine environments by classification societies. It explains how adhesively bonded flat bars of reinforcing beams are used to reinstate buckling and/or local bending capacity, along with the Classification Society regulatory approach to validate this temporary repair until the next drydock visit, meaning up to five years.
Furthermore, the paper shares insights on challenges associated with structural modifications, supply chain logistics, planning, onsite productivity in varying weather conditions, required personnel onboard, the advantages and limitations of cold work techniques for future LNG carriers structural works, and how such repair techniques can be broadly applied across the naval industry.
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