Well if any of you are still there then I am able to tell that I have dug very deep to find information about the VIIC/42 and this is what I've come up with:
It was made to increase the range, crush depth and the offensive power of the VIIC
It was made upon basis of the VIIC hull just like the VIIC/41
The range was extended by widening the saddle tanks with 35 cm, this allowed for an additional 70 tons of fuel which gave it an operational range of app. 12600 nm. The hull was not lengthened as far as I understand which explains why it kept the type designation VIIC, neither was the bow or anything changed from the VIIC/41.
It carried 2 extra torpedoes, total number of 16, how they managed to do this I cannot remember, it had something to do with the conning tower I think.
The extra diving depth was obtained by once again to thicken the hull plating.
It had a slightly higher surface speed 18.6 knots, obtained by an extra boost of the diesel engines. Electric motors the same and submerged topspeed too.
All in all it would have looked almost like a VIIC/41, since cobalt already has made an excellent model of this then a new model will not be necessary. Snorkel was of usual type, deck mounted. The ONLY concern as to modelling will then be the 2 scopes in the con. The rest will be tweaking with the performance files which is a 5 minute job using SH3 mini tweaker.
Are any of you still there and Hitman, would it be possible to clone the IX and VII cons? Not to mention the control room?