Yeah, you know these orc ships are primed and ready for a fight, but their iconography is frankly meaningless if you aren't privy to their culture. Best you can tell is that one appears to be two spike circles looped through each other, another is a fairly bog standard crossed battle axe, and the last one is a basic looking skull with a spear going through it. It [i]could[/i] have some deeper meaning, but it could also just be for intimidation factor.