So despite lunar propaganda claims to the contrary the Lunar port at Corfu was a disastrous failure. Not only did it fail as an entrepôt but not a single deep water ship was ever built there.
But, you ask, what about the Lunar navy that transported lunar soldiers into the Mirrorsea for the amphibious assault on Karse in 1619? The answer to that is delicious- that was a contract with an independent naval power that the Provincial General managed to woo after 1616. Their price was absurdly high, but their down payment was affordable. If barely. Even better, their services were no longer needed after the troops arrive in Karse and so the Empire reneged on the bulk of their agreement with apparent impunity. Better still, with their new Esrolian allies they were able to force these pirates out of the Choralinthor.
After all, what does the Lunar Empire have to fear by betraying a pack of Wolf Pirates and their chief, a wood barbarian called Harrek the Berserk.