Denver-based private equity firm KSL Capital Partners bought a controlling share of Orion Expedition Cruises in mid-May, saying the cruise industry was a unique investment.

Steven Siegel, KSL’s COO, said the firm was impressed by the industry’s recent growth, especially in passenger demand for new ships.

 “We’ve been impressed with how lots of new supply has been readily absorbed,” Siegel said. “Demand seems to have risen to meet that supply.” KSL was also impressed with Orion’s management structure and employee’s skill sets, he said, but did not reveal any further details as why the company is investing in the small niche operator which operates one ship under charter. According to Cruise Industry News’ estimates, Orion has capacity to carry 3,700 passengers in 2008. KSL also did not reveal the size of its investment.

This is the first cruise-related venture for KSL, which said it has previously invested in resorts and country clubs.

“We’ve looked at the cruise industry for a long time,” Siegel said. “It’s a terrific opportunity and we’re excited to be involved with it.” This is the company’s first investment in Australia, where the premier luxury expedition cruise line sails its lone ship, the 4,000-ton Orion. Siegel said the four-year-old, ice-strengthened hull ship was in great shape and will continue Pacific, Antarctic and Asian niche itineraries.

KSL wants to add another ship, Siegel said: either buying a second-hand tonnage or a newbuild. “We’re looking at all possibilities,” he said.