What if Germany found a time displaced submarine a year before invasion of Poland?
While the German Luftwaffe are supporting the Spanish nationalists they spot an odd wrecked ship beached on the Spanish coast.
Spanish nationalists support recovery efforts in trade for further support from Berlin. The Ship is a late 1980s submarine in poor condition, but it's primary systems (navigation, radar, sonar, nuclear power plant and propulsion) are intact enough to study and try to fill in the gaps for what is missing. VLS bays are corroded shut and ordnance has leaked it's fuel but the rockets are physically intact. Same cannot be said for their guidance systems. No nuclear ordinance is present on board but all the signage and documentation that they exist is present. Torpedoes are designed to be submerged and are therefore very much in operational condition. What effect would this have on Germany and the Allies going forward into WW2? Germany likely still loses but how much worse is the cost?