The Maus tank that was recovered by Soviet specialists did not sit idle in the Soviet Union. It was picked apart and its components were sent out for study. The armour composition and hull design were carefully studied. It would be a shame to demolish such a rare exhibit, so only the D-25 was allowed to fire on it, with the performance of other tank guns (the Maus' own 128 mm and the Soviet D-10) being only calculated.
Tank Industry Herald 5-6 1946, p.26
"Calculations of the anti-shell resistance of main armour components
The calculations of resistance to shells of the main hull and turret armour components were performed using the Jacob de Marre formula with Zubrov’s corrections based on the practically obtained limit of complete penetration established by firing at the 160 mm medium hardness armour plate with a 122 mm tank shell. The coefficient K was established to be 1700 and was used to calculate the resistance of the components regardless of the thickness, angle of impact, and type.
The results are given in table 5.
The table shows that not all components completely protect the tank from being penetrated with armour piercing shells fired from already existing guns.
The vertical sides significantly reduce the resistance of the armour and they can be penetrated (at angles of 90 and 270 degrees) with the domestic 100 mm gun.
Conclusions
- The hull of the German Maus tank, composed from large and thick armour plates, is of no significant interest. The only interesting aspect is the method of connecting armoured plates of large dimensions and thicknesses, which can be used on domestic practice.
- The vertical placement of side armour drastically reduces the protection and makes the tank vulnerable in certain conditions.
- The large dimensions of the hull and turret, as well as the significant mass of the armour (105 tons) reduce the tank’s maneuverability."
Component | Thickness (mm) | Angle from normal | Calculated limit of complete penetration, m/s | ||
128 mm gun Vo = 870 | 122 mm gun Vo = 781 | 100 mm gun Vo = 900 | |||
Upper front plate | 200 | 65 | No penetration Vpen = 1200 | No penetration Vpen = 1300 | No penetration Vpen = 1500 |
Lower front plate | 200 | 35 | Penetration Vpen = 850 | No penetration Vpen = 925 | No penetration Vpen = 1050 |
Side | 185 | 0 | Penetration Vpen = 655 | Penetration Vpen = 700 | Penetration Vpen = 805 |
Upper rear | 160 | 35 | Penetration Vpen = 695 | Penetration Vpen = 740 | Penetration Vpen = 845 |
Lower rear | 160 | 30 | Penetration Vpen = 625 | Penetration Vpen = 700 | Penetration Vpen = 798 |
Turret front | 210 | 0 | Penetration Vpen = 780 | No penetration Vpen = 830 | No penetration Vpen = 950 |
Turret side | 210 | 30 | Penetration Vpen = 855 | No penetration Vpen = 920 | No penetration Vpen = 1040 |
Turret rear | 210 | 12 | Penetration Vpen = 755 | No penetration Vpen = 810 | No penetration Vpen = 925 |
To give some reference to the velocities, the D-25's sharp tipped shell drops below 740 m/s at about 700 meters and below 700 m/s at 800 meters and the improved blunt tipped shell at about 750 and 1300 meters respectively, so an IS series tank would have been able to punch through the side of a Maus tank from a respectable distance.
Several interesting points here. One is that the assumption that K=2400 in everyone's favourite table doesn't hold here. The armour in the Maus turned out to be of much lower quality. In this test, armour with K=2030 is referred to as "reduced quality" armour, but the Maus scored even less than that: 1700. K=1700 means that the 160 mm of armour can be penetrated by the D-25 at roughly 2700 meters.
The second is that the "gigantomania" that erupted when the Soviets encountered the Ferdinand turns out to have been justified. The BL-9 gun firing a 122 mm shell at 1000 m/s would have been able to penetrate the Maus in any place other than the upper front plate.