The series that you know as Sea Dogs is called Corsairs in Russia and the CIS, and Sea Dogs: Caribbean Tales is Corsairs 3.
Despite the fact that the third Corsairs game was a mess, Corsairs 4 was still in development until the financial crisis of the late 2000s.
I want to say that Vendetta is Corsairs 4, which never existed. I mean, if Akella was still alive, they could license this game and sell it to a Russian-speaking audience under that name. And no one would suspect anything.
Maybe it's just me, but the influence of Sea Dogs / Corsairs on Vendetta is very well felt. Especially the implementation of naval battles remind me of this series. Naval battles and a huge bunch of bugs in the original Raven's Cry release. :D
I don't know which version of Sea Dogs: Caribbean Tales was released worldwide in those days, but in Russia and the CIS we got barely playable
0.99b on day one. But don't worry, because Vendetta is an improved and polished version of Raven's Cry. It's not the same "mess" under the new name. I know it because I played both versions.
All the other games you mentioned are slightly different. Especially Risen, which (in my humble opinion) is just a Gothic reskin. Vendetta is a brand new game that uses only the engine from Two Worlds II. It's definitely not the same Two Worlds II, where all the characters were replaced with pirates who use ships only as portals. I think you got a reference. (:
P.S. Damn. It sounds like I'm the PR manager of this project. Yo, Reality Pump, call me on my pager!