Supercavitation

Supercavitation is the use of cavitation effects to create a bubble of low-pressure gas (ideally vacuum) wherein an object may travel at great speed while submerged in a liquid. This cavity reduces the drag on the object, which is normally about 1,000 times greater in water than in air.

In 1977, Russian engineers developed the first projectile to use supercavitation: the VA-111 Shkval (squall) torpedo. This can travel at 230 mph (100 m/s), compared to the top speed of about 80 mph (35 m/s) for conventional craft, but is not steerable. News of the device reached the West in the 1990s. Its malfunction was supposedly the cause of the destruction of the K-141 Kursk submarine.

The Naval Undersea Warfare Center in Rhode Island, USA is also working on the phenomenon.

References

• Scientific American, May 2001, "Warp Drive Underwater"