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In another sign of the strength of the expedition cruising market, US-company Lindblad has announced the building of a new polar ship.

The state-of-the-art vessel will be delivered in 2021, adding four new ships to its fleet in five years.

The line, which concentrates on authentic experiences and is focused on the environment and wildlife, launched the National Geographic Quest in July last year.

The National Geographic Venture  will be operating in December this year, and the delivery of the National Geographic Endurance is due in the first quarter of 2020.

The Lindblad Expeditions-National Geographic fleet, which includes the National Geographic Explorer and the National Geographic Orion, is the latest to cash in on the burgeoning expedition market.

Ponant, Hurtigruten, Silversea, and Seabourn have all expanded to meet what marketers are describing as an era when “cold is hot”. Crystal is adding a touch of luxury to cruises to the ice.

Helicopters, submarines and Ponant’s Blue Eye Lounge – an underwater observation area – are all adding to the buzz.

“You can be underneath the water, have a martini and watch a whale go by,”  said Beth Butzlaff, vice president, cruise sales at Virtuoso, a network of luxury travel agencies.

Ms Butzlaff, vice president, cruise sales at Virtuoso, a network of luxury travel agencies, told Cruise Industry News’s expedition report the booming expedition market was being driven in part by the baby boomers.

“There are 76 million of them in the workplace and they are driving the business,” she said, in the 2018 Expedition Cruise Report by Cruise Industry News. “They are younger, they are healthier and they are living longer.”

She added social media was opening up the experience to a wider market, and boomers were bringing their adult children on their expedition cruises.

The trend toward sustainable travel is playing into Lindblad’s expansion.

Sven-Olof Lindblad, President and Chief Executive Officer, said: “We are extremely excited to announce the further expansion of our expedition fleet.

“This is the next step of our long-term growth strategy to capitalise on the expanding demand for high quality adventure travel.

“By marrying additional capacity with a dedicated and growing loyal customer base and fifty years of experience, we will be able to build upon our proven track record of delivering unparalleled expeditions to the world’s most remarkable destinations.”