The objective is a blockade of Russia, the ottoman’s are blocking the black sea and with Denmark occupied the baltic is sealed too, this leave only Arkhangelsk and Vladivostok to recived outside help, is this a good idea? Cam be done? And the consequences ?
Admiral Fishers Baltic Project becomes a realistic possibility when Danes co-operate with the British.
Any even remotely feasible "Baltic Project" would include invading through Denmark, not around it. Which was why the BP was ... unrealistic. The Danes felt much better about selling goullash for the waring parties than participating in any such plans.
but with the field fortifications at Tune you could keep them outside gun range of Copenhagen itself. The fortification of Copenhagen still was a formidable line to breach (similar to Verdun etc.) but had been planned in late 19th century when guns didn't reach that far (Ie Copenhagen was inside bombardment range). But even if an enemy had breached the Tune line he would still have to breach the actual fortifications between Tune and Copenhagen.
You are right about the Tune line, but I doubt it would have been possible to land forces on Zealand and have them march on Copenhagen faster than the Danish army could mobilise at least on Zealand (1/2 the population). So instead of "just" the 50.000 from the partial mobilisation in august 1914 an invader would meet many more, probably closer to 100.000. It would of course be problematic to have mobilised men cross from Jutland and Funen to Zealand but AFAIK the relevant sea routes all were behind minefields and so not accessible for quick naval interdiction, and this is before airpower. AFAIK all of the five infantry Divisions were placed on Zealand, but I have never been able to find any authoritative source on that - like the operational plan. I guess it must be somewhere in the archives, but haven't had the time so far to go look. Anyway an invasion force landing somewhere on Zealand will seriously risk being counterattacked into the sea because the Danish army can mobilise and deploy by rail faster than forces can be landed over sea.Just a nitpick: The Tune Line was not begun until Sep 1915 and it appears that the most likely scenario for German intervention is in the beginning of the war. Even if the Germans had come in 1916 it would not have been entirely finished, it seems. But its function as a deterrent certainly grew as the months of the war rolled by.
I wonder, if push came to shove, would the Germans have been better off trying to cower the Danes into submission by 'doing a Gallipoli' on Copenhagen - simply lining up the HSF and shelling the city from the sea?
The coastal forts around Copenhagen would have to be reduced, though, and mines and subs avoided. But the Bayern class BB's, for example, could lob 15" shells into the city from 22km away. In theory they could shell at least southern Copenhagen and the island of Amager from well out into Køge Bay.
Well, they probably could - eventually - and with the aid of a sizable landing force, but they would not. For the same reasons the British would not attack Denmark - or Germany through Denmark. It simply wasn't worth the effort and risk once the flames rose higher and higher in the other theatres of the war. And I doubt you get a kaiser unwilling to risk his precious battleships vs. the RN to sail a good bunch of them into heavily mined waters, ahem.
P.S A great site here about the Danish fortifications at WWI - with lots of photos and maps