The introduction of "GW-Ferdinand" by Wargaming left me scratching my head.
The first reaction was "yet another fantasy tank!", but I had an hitching feeling about reading a "21cm auf Elefant" somewhere.
The first hint came from the forums, where "Panzer Leader" by Guderian was mentioned as a source.
It is there indeed mentioned as a proposal (among other things, like additional front plating for Tiger, Panther and Panzer IV) but I still was not sure as he seemed to be mixing out stuff. The fact that the 210mm mortar itself was nicknamed "Elefant" due to its weight didn't help of course as it could have allowed further confusion.
"Gunpower 22", by Tadeusz Melleman briefly mentions that heavy self propelled guns on Tiger P chassis were proposed for 150 and 170mm heavy howitzers on page 7, however no source is given, leaving me skeptical about it, although it mentions the same reason for dismissal as Guderian's, economic cost.
This led me to dig deeper into the main authors. A deeper check into "Special Panzer Variants" by Spielberger revealed a "Elefant 21cm on Hummel chassis" proposed on March 1945 but it turned out to be talking about the mortar itself rather than the tank.
"Panzer Tracts 08" gave a precious start, saying in thr Sturmpanzer IV chapter that succesfull production of the model would stop the need for a 21cm Tiger (P) based Stug. This, and the fact that Sturmtiger itself was initially considered to use a similar howitzer, made me consider the possibility of a "Sturmtiger (P)", although still not direct enough to be certain.
"Tiger und seine abarten" by Spielberger finally hit the nail. On pages 104 and 105 (translation courtesy of Silentstalker) it says Hitler wanted the conversion of Porsche Tigers into Sturmgeschütz vehicles with 200mm frontal armor and a 88mm L/71 gun. He also ordered the research of the possibility of installing a 210mm French captured mortars into them. For that, the hull and the superstructure was to be strenghtened.
The order to rebuild one (Porsche vehicle) into a Sturmgeschütz was given by the army high command to Porsche on 26.9.1942. On 14.10.1942 Hitler said that if Panzer IV could have the SIG gun installed, the need for the 88 or 210mm Porsche Tiger Stug has no longer priority and only constructive suggestions should be given from now on.
What does this mean?
Basically, a 210mm assault mortar used as howitzer on a Ferdinand. Same armor, likely slightly different superstructure but definitely a front line tank, not an artillery unit. So, after VK 7201, Wargaming did it again and utterly misread a german design.
Will they ever learn?
Bonus detail: On 5.1.1943 Hitler requested the trials of a 88 L/100 on Tiger P chassis.
Addendum for those that argue about its use in WOT
My articles are purely on an historical perspective although usually based on WOT tanks or events.
My aim is to rectify historical accuracy mistakes, not to create WOT tank designs.
Someone pointed that the armor on a "mortar carrier" would be useless thus it's not logical.
This tank was not meant for facing other tanks tanks but rather bunker defences (which included anti-tank guns) in an urban settings, while the tank role was simply to bring the biggest gun close enough to do the job.
I'll try to explain the role in simple words:
1) Pick a big city (historically, Stalingrad).
2) Infantry discovers a fortified building that indirect fire artillery cannot reach
3) Tank caliber guns fails to breach the reinforced walls
At this point a solution is needed:
Hitler proposed a ramming Tiger vehicle that would act like a motorized battering ram.
Someone a bit less insane proposed a vehicle armored enough to withstand anything thrown at it by bunker defences and with a large enough gun to crack it.
Implementation phase 1: a SIG heavy howitzer is mounted on a Panzer III chassis with 80mm front
Implementation phase 1.5: Hitler wants something bigger and orders the heaviest gun on his favourite engineer's (Porsche) platform
Implementation phase 2: someone saner persuades Hitler that a panzer IV with a 15cm STUH 43 short howitzer and 100mm frontal armor is enough
Implementation phase 2.5: Hitler gets angry and states that nothing less than a Tiger will scare away enemy soldiers from position
Implementation phase 3: Sturmpanzer Bar and Sturmtiger competes for the heavy sturmpanzer role, with Sturmtiger winning the competition.
How would it work in battle in its concept?
The tank would simply approach the enemy strongpoints relying on strong frontal armor to resist anti-tank guns, grenades and anything a fortified position cold fire at it.
Once within range (from a few hundred meters to 1-2 kilometers) the tank would fire with a heavy howitzer and demolish the enemy bunkers either with HE or with a large HEAT demolition shell.
Tanks were not their primary targets and they were not meant to be used as tank destroyers primarily, although that role was occasionally envisioned.
Would they wreck any tank if they fired on it? Yes if close enough to score a direct hit with their low velocity guns.
Would they be optimal for the task? No, as everything in the tank is optimized for short range use against static targets. Perhaps they would be devastating in an ambush, but with the naturally slow rate of fire it would be a waste of heavy shells.
Someone likened heavy sturmpanzers to the soviet SU-ISU 152. It is an analogy with limited purpose, as the german tanks were much more specialized in their role than the soviet design and would be out-ranged by them.