[2023] What are the ways to break through a river filled with Bombers?

I'm pretty new to Polytopia, started playing right before the recent update. Hypothetically, if there was just a river separating myself and an opponent and I completely fill the river with Bombers, is it possible for the opponent to break through? I think the usual counter to Bombers are Rammers and other Bombers, but there would be no tiles connecting their water tiles with my river.

Would 1-2 Knights be able to move into range and kill a Bomber? If so, I'd need a bunch of Defenders in front of the Bombers right? If 1 Knight can 1 shot a Bomber, can 1 Knight just destroy the entire fleet in 1 turn?

Playing my first MP game, still trying to figure out the combat mechanics.