Lloyd’s Register and Carnival drydock LNG cruise vessels

Lloyd’s Register (LR), Carnival UK (CUK) and Carnival Cruise Line (CCL) have successfully completed Europe’s first major LNG drydocking on two large passenger vessels,  Iona and Mardi Gras, marking a significant milestone for LNG-fuelled cruise ships entering their first major renewal survey cycle.
Carnival UK’s Iona and Carnival Cruise Line’s Mardi Gras are two of the earliest LNG-powered cruise ships. The drydocking provides important lessons for the wider cruise sector as it adopts lower-carbon propulsion technologies. The dockings were supported by early and sustained involvement from LR’s Cruise Ship Centre of Expertise (CCoE), which coordinated technical planning, survey alignment and risk management across multiple regions.
Drydocking LNG-fuelled cruise ships presents challenges well beyond those of conventionally-fuelled vessels. Limited drydock windows, complex cryogenic fuel systems and stringent safety requirements demand extensive forward planning, including spare parts procurement with lead times of up to twelve months and early commitment of OEM specialists.
On Mardi Gras, inspections took place during transatlantic sailing, in drydock in Barcelona, and during the subsequent voyage. For Iona, the sequence spanned a voyage from Southampton, the Rotterdam drydock, and a final commissioning voyage that completed the renewal survey cycle.
The need to conduct parts of the LNG inspection programme while the vessels were in service and carrying passengers presented a challenge, requiring detailed isolation and safety planning between ship crews, Carnival engineering teams, and LR surveyors.
LR worked with Carnival teams for more than a year prior to drydocking, conducting ship visits, risk assessments and technical workshops across various locations. Survey strategies were tailored to each vessel’s operational constraints. Iona, operating regularly in Norway’s fjords, required continuous LNG availability to maintain NOx Tier III compliance, while Mardi Gras needed one LNG tank and propulsion line fully operational during its transatlantic passage to remain within Safe Return to Port limits.
“All inspections and surveys were completed safely, on time and to the satisfaction of all parties,” said Remco van Ee, Senior Surveyor in Charge at LR, highlighting the contribution of LR survey teams across Europe and the US.
For Carnival, the projects provided valuable insight into LNG system maintenance and renewal planning, helping to minimise operational disruption and strengthen future drydocking strategies. LR said the lessons learned will influence future alternative-fuel ship designs, maintenance practices and survey requirements as LNG fleets expand and the industry moves towards methanol, biofuels and synthetic fuels.