WI/AHC: Armada Of 1779 Goes Forward?

[Matteo]

With which line of supply ?

Sorry but though unprobable, you have to admit that if a big land power succeeds in invading Britain, then the wooden fortress is no use because there is no strong british land army to resist successfully.

The financial system that was the key advantage of Britain crashes immediately.
The empire is beheaded.
The fleet very quickly becomes useless because without its admiralty and its key harbours, it can't operate usefully.
Ireland revolts. India revolts.
The french canadians revolt.
The british army in America does not keep on figthing american insurgents nor ally with them. It either disbands or tried to find a way to go back home in the "least worse" conditions.
The british oligarchy tried to strike a deal with with the invadors to save what can be saved. And it will be a very hard deal because this defeat is by nature crushing and decisive and if they don't strike a deal the people will revolt because they won't fight for a german king and an oligarchy of high nobles, baskets and high perchants that such their blood.
It's the same thing as the germans defeating France in 1940 : submission or total collapse.

Then you will have a war in America between France and the 13 colonies.

 

[funnyhat]

They will fight on hoping to turn the war around in America

That's a tough question

That's hard for me to imagine. If London falls, I think it's much more likely that British troop morale in America collapses and their leadership calls for a rapid armistice with the United States.

It'd be interesting how that might affect the revolution? Maybe a Franco-American alliance would change the discourse on Monarchy in the US enough for Washington to accept the crown, possible as a counter-weight to a much more powerful Kingdom of France. If the French can indeed get Canada back this could lead to tensions with the Americans about the question of manifest destiny and who has the right to what land, not to mention the already discussed animosity of their ally spain towards the rising 13 colonies.

By 1779 I think the genie was out of the bottle - there is probably no going back to George III at that point. There could indeed be problems with France if France gets Canada back, but the latter may not be a certainty; France had not been enamored with the Canada colony in the first place, as it hadn't been very profitable.
What France is going to want above all is more sugar islands in the Caribbean.