At the time I put my faith in figures recorded for CMA CGM Libra, putting it slightly ahead.
Despite the nominal 11,040 TEUs quoted, the 10,980 TEU capacity used by many sources and the 8,108 TEU if loaded to an average 14 tonnes, there is still a case to be made for the CMA CGM Thalassa because it has the larger deadweight tonnage of 131,938 tonnes, and can carry more loaded containers. Simply put CMA CGM Thalassa can carry more cargo even though it is not the bigger ship in dimensions.
The declared container capacity of a ship and the actual number of containers it can actually carry may be somewhat less. Some lines are coy and understate the capacity and others overstate it. Deadweight tonnage also varies because it depends on the allowed draft. If the calculation is made for the ship at the deepest draft condition, then that is the ultimate carrying capacity. It is not always clear without access to more detailed information whether the quoted deadweight tonnage is in fact the maximum.
No matter if it is the biggest or not, it was an impressive sight arriving this afternoon and towering over the attending tugs and the harbour tour boat Silva of Halifax.