A couple days ago I wrote that I wouldn't mind getting rid of an entire German armed service.
Now my challenge to (German) readers:
Offer me an example for collective defence (NATO or EU being under attack by a foreign government's armed services) in which a German navy is necessary to keep Germany from getting blockaded, bombed or invaded/occupied or necessary to reconquer/defend an ally that got blockaded, bombed or invaded & occupied!*
Phrases such as "Germany's navy would seal off the Baltic Sea exit for Russian navy" don't count. If that was really important and likely, the Russians could simply order those Baltic Fleet units to deploy to the Northern Fleet prior to a hot conflict.
Phrases about German ports needing naval mineclearing don't count either, since there are minehunter ships in allied navies as well, and the small Baltic Sea ports would hardly be used during a hot conflict (for safety reasons).
I think it's obvious that a German naval presence would hardly be felt in a Mediterranean conflict, but such a conflict is super-unlikely for want of a threat anyway.**
A Eastern European conflict on the other hand requires a super-quick deployment (or predeployment) of ground combat (and air defence) forces, as well as air power intervention. Navies would be utter sideshows unless the conflict escalated to the Atlantic Ocean, and in that case a German navy would hardly be felt either.
One might say that keeping a navy just in case, as a pool of competence, would make sense. That's the ideology of balanced military forces - as if having a coastline inevitably makes a navy necessary (regardless of allies), even though landlocked allies do not need a navy at all (with equal apparent self-evidence).
I counter this with the 100+ year track record of German navy uselessness. I don't think it's worth spending billions waiting for a mythical time in which a German navy makes sense for a change. We wouldn't even have much use (and thus not any need) for it if we were alone and without allies again.
This is not a proposal for Germany to freeride on allied efforts. It's a proposal to tailor the armed services for collective deterrence and defence. Our geographic location puts an above-average burden on us as early defender of Eastern frontier allies. The navy is a mere distraction to this.
*: I wrote this rather complicated set of requirements because it's unrealistic to demand that military power prevents every alliance member from even only temporary naval blockade, air attack or hostile forces incursions.
**: Israel is the only somewhat relevant non-allied power there, and it's extremely unlikely that it attacks NATO or the EU..