Weeeeeelllllll....not totally unrealistic on some level.
Anywho:
Gneis getting sunk against Hood is going to do nothing to convince Hitler of anything. Except perhaps that the surface fleet isn't worth the money. Remember, when Bismarck actually sank Hood her own sinking was still considered a waste of money by Hitler. It was part of the reason that the KM didn't go on any more Atlantic adventures other than U-Boats. In this case, Gneis did crippling damage to Hood...but did not sink her. Repulse came away with no damage at all, while Scharn got shot up a bit as well since the Terrible Twins focused on Hood. So you've got a trade of one crippled-but-repairable battlecruiser for one sunk/one damaged battleship(cruiser) -depending on who you ask on what the Twins are. When the Brits have two intact CCs still, plus a lot more (if old) battleships. Plus more coming up soon enough.
Not as great a showing to someone who wants IMPRESSIVE FEATS like Hitler, is it?
Furthermore, while it's a twisted one...Hitler- before he went completely off the deep end -operated on logic. If you want to appeal to him, you have to know how to appeal to him. Trying to delay the Navy's next big operation, the one that is supposed to convince him it isn't a waste of money? There's a reason that Lutjens stopped delaying it IRL, and its much the same here. Delay too long, and Hitler will- in one of his famous mood swings -decide the surface fleet isn't worth the money.
Moreover...Schreiber is already using his influence to get the extra AA, as I said before. That's a delay in itself.
As for Tirp...well. Historically, she wasn't taken because her fitting out took longer than it was supposed to. According to my handy Hitler's Navy book...not until October of '41. In that regard...who is saying Schreiber wants to wait for little sister? Let me put two dates here:
October '41. When Tirp was finished fitting out historically, and this might be delayed further because of the extra AA she'll get.
June 22, 1941
Anyone know what day that is?
The thing about the German surface navy was that it
was a waste of money and resources. That it accomplished what it did is an indication of the competence and preparation problems the Royal Navy had in WW2.
Now, that's not to say that if Hitler had listened to Doenitz and had 300 operational submarines by the onset of the war, he could have quickly knocked Britain out of the war--that's simply an overestimation of his own subs' capabilities and an underestimation of his enemies'--but he would have had a real shot at knocking Britain out of the war in the longer term, provided he could keep up the kind of catastrophic shipping losses for more than a few months at a time. He certainly would have crippled Britain's war effort. If Hitler hadn't fucked up Dunkirk completely, Doenitz's submarine campaign (bolstered by much greater numbers) might have been the nail in the coffin for Britain's war effort.
Where Doenitz went wrong, ultimately, wasn't that he didn't have enough subs--though it certainly limited the amount of damage he could inflict when the tide of the sub war in the Atlantic was in his favor--it was that he didn't push for much in the way of innovation and introducing more advanced classes of submarine. The German submarine of 1939 was remarkably similar, technology-wise, to the vast majority of the submarine fleet in 1945. If, instead of waiting for the very-long-term development of the dream submarines, he had pushed for the development of the intermediate subs (what ultimately became the "electric boats" of 1945) and construction of such ship classes as soon was at all practical, he'd have been able to match Allied advances in ASW tech, doctrine, and escort numbers/types.
That Hitler
completely failed to recognize how having a surface navy with capital ships had worked out for Germany in WW1 is a mark of his general lack of competence and understanding of warfare that wasn't on the ground. In WW1, Germany had a huge surface navy, such that it actually managed to do a straight-up battle with the entire British line and come out on top, tactically speaking. But that's all they accomplished. The submarine arm, on the other hand,
nearly starved Britain out of the war. Only adopting a convoy system saved Britain by making targets a LOT harder to find and somewhat harder to attack safely.
Doenitz was a visionary in many respects--his wolfpack system to counter the convoy system, his insistence on practical training for night-time surface attack, insistence on excellent periscopes and other gadgets, his vision that a large submarine force could do what Germany needed--defeat or effectively cripple Britain in a naval war, but without exceeding Germany's resources or industrial limits like a huge surface navy would--but Hitler didn't really listen to him much until it was too late. And Doenitz himself didn't appreciate the need to advance the technology of his subs until it was far, far too late.
You can see the difference between him and Lockwood (the eventual commander of US submarines) fairly clearly: Doenitz envisioned wolfpack tactics to counter convoys, directing the wolfpacks himself in real time, and continued to insist that greater numbers of submarines would make the difference. Lockwood was reluctant to try wolfpack tactics, but eventually decided to experiment with them (and eventually adopt them), with wolfpack tactics being taught by submariners and conducted by the ranking sub skipper in the pack. He believed, however, that the decisive difference over time would be made with more advanced technology, and he was largely correct (though numbers did help considerably to increase the scale of his victories): US submarines, conducting accurate, sometimes relentless, and seemingly-impossible attacks became the terror of Japanese seamen--unbeknownst to them, US submarines would be able to find targets from long range in total darkness with surface-search radar, get accurate range and heading estimates with another radar set, and fire large spreads--up to six torpedoes at once, sometimes followed by four more after swinging the sub around--of torpedoes, some of them wakeless. By the late period of the war, US submarines were penetrating the Sea of Japan (like the Mediterranean Sea, but worse, because Japan fully controlled every inch of the sea and its narrow entrances/exits), detecting underwater mines with new, highly sensitive sonar and slipping through the minefield cables with specifically-fitted wire attachments of their own. They had acoustic homing torpedoes for disabling or taking out escorts trying to find them, and effective air search radar that could be deployed from underwater.
Frankly, the only surface warships beyond destroyer size that Germany had any business building were commerce-raiding cruisers--but even that was a risky endeavor. Convoy tactics would still make ships hard to find. If Britain tried to make convoys few in number but huge in size, and escorted those few convoys with sufficient numbers of light and heavy cruisers (and aircraft carriers, where available), the commerce-raider cruisers would have had to team up to have had a chance at effectiveness.
Even the invasion of Norway was a matter of luck and Royal Navy incompetence (plus some extremely underhanded methods, like inviting neutral warships to parley, only to preemptively open fire on them after they agreed and came close). And
even then, the KM lost half of its destroyers and a light cruiser.
