It would be hard for the Casse to maintain a fleet against any of the mainland factions if certain houserules were instituted. Namely that ships in ports being blockaded cannot leave without beating back the blockaders. That being said, conservatively it takes about 20 years to gain all of the British Isles at which point you are raking in the money. The Gauls would beat each other bloody and the Sweboz aren't much good at naval invasions either so I think the Casse could come to dominate most of Northern Europe before whoever won the Carthage/Rome duel showed up.