Hello Time4Tea!
Maybe I have missed it, or misinterpret the type of roleplaying games you are looking for, but have you tried "Anachronox" (from the former studio Ion Storm)?
Gameplay in "Anachronox" is a mix of the so-called Japanese roleplaying games (think of Dragon Quest or Final Fantasy) with separate turn-based battlescreen and point and click adventure game in a stylish sci-fi setting. It has a lot of quirks and humor! Unfortunately, its biggest downside is the cliff-hanger ending, because the studio closed before being able to continue the story. What is in there with respect to story and character plots is well developed, though.
Definitely, recomended, and it is available here on GOG.com!
Another far stretch might be the "Sea Dogs" series of games (originally by the Russian developer Akella). Think of real time sea faring battles during the age of sails mixed in with a simple trading model, (a little bit of land) exploration, clumsy sword fighting and somewhat light roleplaying mechanics regarding ship upgrades, ship maintenance and character progression. My biggest problem with the games are the lack of character generation (some games in the series let you at least choose from very small options) and an unintuitive control scheme, which needs some time to get acustomed to.
GOG.com has three of the games, which were have been translated and released in the West, titled "Sea Dogs" (the actual first game), "Sea Dogs: Caribbean Tales" (formerly known as "Age of Pirates: Caribbean Tales" resembling somewhat the third installment) and "Sea Dogs: City of Abandoned Ships" (formerly known as "Age of Pirates 2: City of Abandoned Ships" in the West). Unfortunately, in my opinion at least, the newer the game in the series does NOT mean it is better!
"Sea Dogs (2000)" (I) and "Sea Dogs: Caribbean Tales (2006)" (III) are more freeform, sandboxy games and severly lack in the story department. "Sea Dogs: City of Abandoned Ships (2009)" has more characters and plot quest to choose from, but I absolutely do not like the level-scaling (similar to original, vanilla TES IV Oblivion!), which destroys for me the feeling of or perception of progression in the game. I have no experience with the most recent one, "Sea Dogs: To Each His Own (2012)" (available on Steam), but heard it involves quests with time limits and still has quite a lot of bugs.
To be honest each of these games had a very buggy release, but in my case seem to be relatively stable.
My favourite of the Sea Dogs series is the second entry, "Pirates of the Caribbean (2003)", which actual has only very loose references to its title's licence! Unfortunately, it is not available for purchase in digital format, only second hand retail copies. Despite its lower resolution, console like user interface with huge buttons and text font (it had been released on the original Xbox, as well) and older game engine, I think it has the best atmosphere and much cleaner well-rounded overall aesthetic and gameplay. The north american PC release has a little bit weaker graphical fidelity in its water shaders (less environmental reflections), but does not come with the horrenous copy protections of the superior European releases.
I can not vouch for the diverse community modifications, since I prefer to play the games in their (almost) original/vanilla form (except for patches to fix severe bugs). Some of these are, for instance, Build Engine12/13 or New Horizons for "Pirates of the Caribbean", Historical Immersion Mod [aka Supermod] for "Caribbean Tales" and Gentlemen of Fortune for "City of Abandoned Ships". One reason for me to not play with those modifications are their impact on the sea / water animation, resulting in a more oily appearance, especially when it is darker in the ingame evening or night times. Again, I still prefer the smooth representation of the sea and colors in the stock, vanilla "Pirates of the Caribbean" (Sea Dogs II) and its better matching ship movement on the waves.
Other games (to a degree similar to Sea Dogs series) with a pirate themed setting, such as Man o War Corsair, Tempest, Blood & Gold Caribbean, did not appeal to me aesthetically and lacked in the depiction of sailing (wind effect). From the Risen series, I would recommend primarily the first one. It has more of a mediterrain setting, is exclusively on land and very similar to the Gothic trilogy (same developer). The second Risen game is more of a pirate setting and has only a limited bit of sea faring included.
Maybe, I went totally offtopic, I do not know. ;-)
Kind regards,
foxgog