GrumpyElk: You can choose the resolution in which you want to play the game by manually editing the engine.ini in your City of Abandoned Ships folder with wordpad.

Insert the resolution values into the lines
screen_x and screen_y:

This is what i use, but you may want to edit the values differently:
screen_x = 2560
screen_y = 1440

I heard that there maybe problems with the loading screen, UI, Inventory, because the game has a 4:3 aspect ratio as default. In most cases your screen should look somehow stretched.

This is what seems to fix it:

Go to

Sea Dogs - City of Abandoned Ships\Program\INTERFACE\interface.c

and also edit it with wordpad

search the following line:
showWindow.aspectRatio = (h*4.0)/(w*3.0);

and change it to:
showWindow.aspectRatio = 1.0;

Just in case, backup your files before you change them.

It took me some time to figure it out, so i wanted to share and probably save you some time.
I hope it helps and you enjoy your game even more.