[Uyraell]

A slight amendment to your post, if I may, Spacemen1969.

I'm not certain how accurate "modern" (post 1990) information is, But the info in my hands puts matters somewhat as follows, allowing for a bit of paraphrasing.
{Please don't think I'm trying to nit-pick or rivet-count: neither is the case, it's just that it's not the first time I've seen the Type XXIII erroneously named "Elektroboot" in print.}

Type XXI (21) was the "Elektroboot" due to having battery capacity far in excess (almost three times greater than that) of any prior Kreigsmarine U-boot class. This was because the XXI hull had originally been designed with provision for the Walter "Ingolin" Hydrogen Peroxide closed-cycle engine intended for both the Type XXI and the Type XXIII, through to Type XXVIII.
Most of the Types after Type XXIII remained paper projects only.

There is anecdotal evidence to suggest the Type XXIII received the unofficial German nickname "Meteor" or "Meteorite" which is why the Royal Navy named it's captured test example HMS Meteorite.
At any rate, the British proved they could neither maintain nor successfully run that vessel, decided the Ingolin Technology was "obsolete" and thus scrapped the only known (if I recall correctly) surviving example of the Type XXIII. Records show the British did achieve the then (1946 or 1947) phenomenally high underwater speed of 22 to 25 knots or so, in HMS Meteorite.

Such a high submerged speed by a manned vessel was not to be again achieved until the advent of the American Albacore and Skipjack classes of submarines some ten or fifteen years later, and which proved capable of speeds comfortably in excess of 25 knots, sometimes as high as 40 knots.

A long way off topic, perhaps, and I hope I'm forgiven that.
However, the Ingolin U-boots and their descendants and offshoots (either Western or Russian) have long been of great interest to me.

The Russian "Whiskey I" class and "Sierra I" classes both take their hull forms from the Type XXI, as does the British Oberon and the French Daphne classes. So far as I am aware, all of those classes are now many years retired.

The USS Nautilus is basically an oversized Type XXI with the nuclear powerplant replacing the Ingolin powerplant of the Type XXI.

I hope the info is of interest and help to you, Spacemen1969.

Kind and Respectful Regards, Uyraell.