Viking Ocean

(4:35 p.m. EDT) -- Viking Ocean Cruises' fleet will expand to 10 ships after the line confirmed four more newbuilds, according to Fincantieri shipyard. Today's order achieves one part of Viking CEO Torstein Hagen's long-held ambition to have 10 ocean vessels and 100 river-based longships.

"Following the agreement signed last April between Fincantieri and Viking Ocean Cruises, the contracts for the construction of the 7th and 8th ships have become effective and, furthermore, the company has exercised the option for the 9th and the 10th unit," a statement said.

The new ships will be the same size and design as the two Viking Ocean vessels already ordered and the four in operation: Viking Sea, Viking Star, Viking Sky and Viking Sun, which were built at other Italian shipyards in Marghera and Ancona.

The six new sister ships, including those related to the exercised option, will be delivered in 2018, 2019, 2021, two in 2022 and the last one in 2023.

--By Louise Goldsbury, Australia Editor