They would have a BUNCH of scorpion bows deployed at Kings Landing.
That sort of goes to another thing I noticed.
How did Euron get so many ships built in such a short time? It would take years to build that many ships. Even when the British Empire was at its height, getting a warship "ship shape in Bristol fashion" would take a long time.
But Euron Greyjoy shows up with hundreds of top line warships. And building those Scorpion arrow platforms takes time.