The vessel will be based at Bremerhaven and is able to transport up to four wind turbines at a time for installation at depths of over 40 metres.
Nordsee Ost is set to be completed in 2013. It will consist of 48 Repower 6.15MW turbines.
RWE said the ship was built in South Korea, although it pointed out that around 40% of its €100 million cost went to German companies.
A sister ship, the Friedrich Ernestine, is also being constructed. This will be used to build the Gwynt y Mor wind farm off the coast of Wales.
Speaking about the launch of the new ship RWE CEO Fritz Vahrenholt said: "The "Victoria Mathias" is the result of a very fruitful combination of Korean and European, especially German, engineering. German companies account for 40% of the added value, and Europe as a whole, more than 60 percent.
"The work will be completed by the German shipyard company Lloyd Werft, who are our host today. Victoria Mathias and her sister vessel Friedrich Ernestine, which is identical in design, are important elements in the construction of our ambitious offshore pipeline."