I really think that there needs to be flags for both sides during a skirmish no matter what, because you end up with skirmishes like the one in the image below where it may as well be a siege; the problem is the AI has a boat off the coast out of range of my crossbows, unfortunately I dont have transport galleys tech so I'm just locked into this battle trying to take pot shots at his boat while he can continue to reinforce the battle.