First off, I understand that it's just a beta and that you should understand that this is a simple explanation of what I like / dislike, it's called asked constructive criticism not "trolling".
First impressions and suggestions:
The "pirates" should have their own melee weapons, I mean who's ever heard of a pirate plundering and murdering with a wooden fork? Maybe such weapons as pistols and sickles would greatly improve the beta.
The "marines" are just... ugh; they made me cringe with their simplicity and all around 'un-uniqueness', maybe they should be able to do special things that normal infantry can't do like swimming. This goes for the "pirates" too, when in water you did have to double tap space bar to turn on swimming mode.
The boats: the massive corvettes are simply b-e-a-utiful and are my favourite aspect of the beta, but they can't move; of course I understand the time and almost impossibility of programming them to be able to move so I suggest, please improve the looks of the small boats. I mean I could live with their uglyness in NW but seeing them in a supposed "naval" beta then their realism and detail should be improved.
That's all I have for now, keep plundering me hearties.