Deep wading

This makes it different from the less extreme "wading" done by many off-road vehicles which are simply fitted with a snorkel that is higher than the normal engine air intake, roughly level with the top of the cab.

These tanks were given waterproofed hulls and air intake and exhaust trunking to allow them to come ashore from shallow water.

Tall ducts extended from the engine deck to above the turret top and they needed to stay above water.

The Tiger was the first tank to come with deep fording ability as designed, although the earlier Tauchpanzer, a modification of the Panzer III and Panzer IV, was designed to drive on the sea-bed, part of the German preparations for Operation Sea Lion, the planned invasion of Britain in 1941.

During the Cold War, deep fording was particularly valuable to NATO and Soviet forces in Europe where operations required numerous river crossings.

The Leopard 2 uses a snorkel assembled by stacking shorter rings; the tube's height is limited to about three metres and is mounted on the crew commander's hatch.