Whichever you choose, please consider displaying the controls inside the game, at least during the setup screen, don't make the user search for controls in the wiki. :)

Also the hp bar below the minimap is a bit weird, would expect it the same as enemy ships above my ship, so i can see if i'm winning or losing a cannon exchange like in a rts game. Or at least someplace more convenient to quickly glance at nearer the center of the screen.

Very fun game by the way, well done! Scratches the nostalgia itch of 'Corsairs Gold' for me.

Space to fire makes more sense than shift to fire

Edit: Shift is a modifier key. Hold shift to go from lowercase -> capitals. In FPS games shift is walking -> running. In RTS games shift is "select one of these units -> select all of these units"

I know your game doesn't have to follow these rules, you can do whatever you want. However it's worth thinking about what "language" each key on the keyboard is speaking when you want to use it.