[@Dawnscroll]
You are forgetting, the Iron born have been independent since Daenerys Targaryen re took Westeros, Bluetommy allowed that

I NEVER said they were amazing fighters, I said their better at ship to ship hn the Northman
I extended the time it would have taken them to get to Torrhen square, theyd lose almost half of their 40 strong fleet.

The Galleyes can LITERALLY smash the longships! Thats a shit ton of dead ironborn early in the fight, and 300 years  to build and train a navy does not match a millenia of Naval experience.

The Northman ARE superior fighters in general, they are also more loyal, but they have not lived their lives on the deck of a ship.

The Ironborn are nor untouchable, if they were the westerlands would be no more, as it stands Jakkon took only fair Isle

I will say, the belief that the Ironborn would stopm the north is ridiculous, neither side has a real trumpcard. Torrhen square is home in the north, this far Inland your ships have the advantage but it will not be a slaughter! I was personally not a fan of the slaughter that was Bear Island, it was strangely unimpressive for such an ancient house whose words are "Here we Stand" and all they did was sit the fuck down.

NO ONE has a trump card, Ironborn are NOT legendary fighters, but they have lived and fought on ships their whole lives. They are far from home, and will pay dearly, I expect no more than 10 ships return from Jakkons fleet, but it isn't a slaughter cause they will fight until they break, and unlike the north theey WILL break. They WILL lose the will to fight, your men will not