Just want to draw everybody's attention to the Ship Simulator Pro website, in particular the Boats page.
http://www.shipsimpro.com/vessels/ (http://www.shipsimpro.com/vessels/)
Now if we look at the Ship Sim Gamescom Trailer, at 51 seconds the two frigates are different classes. I suspect that they are the Karel Doorman Class Frigate, and the La Fayette Class Frigate.
Also, the specs sheet for the vessels are there too, which should make for some interesting reading....