That’s S-Tank, not “stank.”
The Swedish Stridsvagn 103 was a very unique design. When you think of the classic tank, you think of an armored hull on tracks, and a turret mounting the main gun.
The S103 instead dispensed with the turret, and fixed an auto-loading 105mm main gun to the hull. The gun was aimed by the driver/gunner by pivoting the tracks, and elevated or depressed via the hydraulic suspension system. This provided a relatively low profile vehicle. The drawback was that it could not fire accurately on the move, but since the Swedes saw its use as primarily defensive, that was not a terrible shortcoming to them.
While the design stressed avoiding being hit, attention was also paid to mitigating the effects of the vehicle being hit. And did they ever shoot the heck out of some prototypes to test it.
Be sure to hit the “cc” button for closed captions.
The S103 was developed in the early 1960s and entered into service in the late 1960s, with production ending in 1971 after 290 had been delivered.
Not content merely to have one weird major design feature, the S103 also had a very unique powerplant. A base diesel powerplant was used for slow movement and for aiming the gun. For higher speed operations, a gas turbine was also installed to boost power.
Retired in 1997, the S103 was replaced by a modified German built Leopard 2A5 known as the S122.