How much would prewar German long-range wire-guided torpedoes, especially combined with snorkels, improve U-boat effectiveness?
Short answerThey would provide a dangerous early advantage, but limited German numbers and British intelligence and countermeasure development would erode it.
NotesA 20-25 km guided weapon with a larger warhead would enlarge the submarine's engagement area and create a serious early-war threat. Its development would leak, opponents would search for counters, and an area-effect ASW weapon might even be used to sever the guidance wire. Germany's initially small submarine force would also give Britain opportunities to learn before the system could be fielded in mass.