Natter: It's amazing that geman torpedoes were in use after the war and received updating with wire-guidance!
Sorry, for a late reply: yet again, there's no notice from the forum.
Yes, both danish and norwegian navies made their own wireguidance-version of the G7a(TI) in the mid 60's. The danish version was designated "T1T" (T for "trådstyrt", ie wireguided), while the norwegian version was designated "T1 mod 1". I don't remember when the danish T1T were phased out, but they didn't use them as long as us. Both mods were similar, but not compatible (we have a couple of the danish modded gyroscopes at Herdla).
The T1 mod 1 received 3 additional modifications - the last one in 1992, when the old electronics was replaced with a fully computerized module, introducing two-way datacommunication with the firecontrolsystem. Originally, the controlsystem only transmitted single pulses - each pulse changing the course by one degree port/starboard. After the modification, the torpedo would receive full information on the targets position, course and speeed, as well as it's own position, waypoints etc (we could also launch torpedoes continuously, not having to wait for the previous engagement to finish: The FCS could handle 50 targets and 8 torpedoes in the sea, also reassigning targets after launch ++). There were also a newly developed speedsensor fitted to the torpedo, to get more relibale speedmeasurments. This way, the torpedo could track the target based on the last updated info in case the guidance wire broke (a common problem - especially with salvos of 2-4 torpedoes). If the torpedo missed the expected location of the target, a computer-controlled "search-pattern" would be initiated.
The torpedo was finally phased out in 1999, replaced by the more modern swedish TP613 (a combined wireguided/acoustic seeker torpedo).
Mechanically, the german torpedo worked just as well as they did in the 1940's - even after hundreds of exersiceshots. The only problem (and what finally sealed it's fate) was increased internal corrosion of the airtanks, making it too hazardous filling it with pressurized air (for the last year or so, there were restrictions on max pressure, and we could only use torpedoes that had been x-rayed and inspected thoroughly for corrosion and that met a minimum standard for thickness of the goods in the airtank).