How and where the northmen should build a western harbor and fleet ?

[Corvo the Crow]

1 hour ago, Craving Peaches said:

First Men had thousands of years before the Andals came along to construct more than one citadel. Can't blame the Andals for that.

You don’t know that, we don’t know how long after the Citadel Andouilles came. Also Westeros just has 5 cities and though neither of them has anything to do with Andouilles, 2 of them, KL and WH were only built after the invasions. I suspect that Lannisport and Gulltown weren’t proper cities either. Even the biggest city until KL, Oldtown is named town so probably nowhere else had a sizable population -and economy- outside of Oldtown. 
You see, despite being in Westeros for several thousand years Andouilles couldn’t even found a city. The exiled Manderlys, who are of First Men stock( they were probably on the brink of it before they were exiled and this was probably why they were exiled) while the invading Targaryens, of incestous Valyrian stock, founded cities after the invasions but Andals? Not a single one. 

[Terrorthatflapsinthenight9]

A loan from the Iron Bank of Braavos, with an accord on northern lumber going to Braavos, a place in constant need of wood, could be useful into helping that project come to fruition.