River Cruise Certares invests in AmaWaterways By Michelle Baran / May 17, 2017 Share 1 AmaWaterways' Rudi Schreiner and Kristen Karst at the podium during the naming of the AmaKristina. Certares joins Schreiner and Karst as an investor in the line. Photo Credit: Jeri Clausing -- AmaWaterways has closed on an investment from New York-based travel and hospitality investor group Certares LP, a company that also has stakes in American Express Global Business Travel and Travel Leaders Group.Certares joins the husband and wife team of Rudi Schreiner and Kristin Karst along with the Murphy and McGeary families as the company's fourth investor. The firm holds and oversees each of its portfolio companies separately. Terms of the transaction were not disclosed.The news comes as the 15-year-old AmaWaterways christened its newest ship, the AmaKristina, in Lahnstein, Germany, last week. The company also recently unveiled design and construction plans for a Danube river cruise vessel that will be twice as wide as its existing ships, the AmaMagna, which is slated to launch in 2019.AmaWaterways stated that all of its existing investors "remain committed to supporting AmaWaterways' long-term growth and innovation in the river cruising industry."AmaWaterways has a fleet of 20 vessels, including some that it charters, that sail throughout Europe, on Southeast Asia's Mekong River and on the Chobe River in Africa.