Order the KM to thoroughly test it's torpedoes and then do the classic Supervillian + Piranha Tank + Incompetent Subordinates stick once it's clear how bad they suck. Getting those fixed by September 1939 doesn't require ASBs, just a healthy respect for Murphys Law instead of assuming that superior German engineering will magically make everything work to specs. And manufacturing torpedoes that work doesn't cost more resources than manufacturing duds. Other low-cost things that could have been done without drawing away resources from Heer and LW: as tigercat wrote. Raiders, Minelayers, etc. Train bomber pilots for anti-shipping missions not just ground strikes. Make Göring share recon planes.