SEALs v Sharks 1: Bang!

What are Special Forces likely to carry underwater when they're expecting opposition? If they're facing mere humans, options range from the amphibious Glock 17 to a mean Russian underwater assault rifle, as I explain in my Wired News piece, Splash Splash You're Dead. But if the threat comes from sharks, they may want something better than a handgun - remember Roy Scheider emptying his piece into the passing Great White in Jaws, with absolutely no effect?

A common weapon for shark protection underwater is the "bang stick," essentially a pole with a cartridge on the end which is triggered by contact. Many of these are home-made by divers, or you can buy them ready made.

Shotgun cartridges are favored for power, but while getting the right grade of shot is important for hunters, underwater it makes no difference. The projectile is almost irrelevant; in fact, a study found that having a projectile in the cartridge actually makes it less effective.

This is because the injury mechanism is very different in water than in air. Underwater, it's not the buckshot which does the damage, it's the shockwave from the expanding gas. Water is hundreds of times denser than air and incompressible, making the shockwaves are that much more potent.

This was the principle behind the U.S. Navy's "ultimate weapon" for divers, the Seaway bang stick. The lethal end used two cartridges stuck face to face, one a rifle cartridge and the other .38, with no projectile. It was packed with a more powerful charge than normal rounds, as a bang stick is not limited by the pressure the gun can handle.

According to diver Douglas Peterson,the weapon was frighteningly effective, even against twelve-foot sharks:

*I saw a shark, no correct that, including the film footage, I saw dozens of sharks cut in two... up to 12' long. The one I saw hit in the water was struck just above the gills and it literally blew the head off the shark, he rolled over and sank with the head barely attached by a tiny piece of skin tissue. In fact, of the dozens
I saw killed in the test film, all but a few simply stopped moving and sank instantaneously, usually in two chunks. *

The shockwave from the bang stick was so great that the user was advised to look directly towards the point of impact otherwise there was a risk of eardrum rupture.

With previous bang sticks the spent cartridge has to be extracted by hand, but the Seaway design also ejected the spent cartridge so the bang stick could be reloaded immediately from a bandolier.

The Seaway bang stick was only produced in limited numbers; it was not a success commercially because the specialized cartridges were very expensive and difficult to obtain. It was clearly a hellishly powerful weapon for dealing with hostile sea creatures. But maybe something more sophisticated was needed…