How was Dagon able to wreak havoc with the Arbor and its huge Redwyne fleet so close by? Or do you think the Redwynes only built their huge fleet afterwards?

Dagon likely waited until a big wine shipment had left and then executed a quick hit-and-run, given that Pycelle described his style as “as soon as we move against him he will back to Pyke, as Lord Dagon was wont to do in his day.“