USS Vesuvius (1888) - Dynamite Guns

Dynamite Guns

Vesuvius carried three 15-inch (38-cm) cast iron pneumatic guns, mounted forward side-by-side at a fixed elevation of 16 degrees. Gun barrels were 55 feet (17 meters) long with the muzzles 15 feet (4.6 meters) above the deck 37 feet (11 meters) abaft the bow. In order to train these weapons, the ship had to be aimed, like a gun, at its target. Compressed air from a 1000 psi (70 atm) reservoir projected the shells from the "dynamite guns." Two air compressors were available to recharge the reservoir.

The shells fired from the guns were steel or brass casings 7 feet (2 meters) long with the explosive contained in the conical forward part of the casing and spiral vanes on the after part to rotate the projectile. The explosive used in the shells themselves was actually a "desensitized blasting gelatin" composed of nitrocellulose and nitroglycerine. It was less sensitive to shock than regular dynamite but still sensitive enough that compressed air, rather than powder, had to be utilized as the propellant. Shells containing 550 pounds (250 kg) of explosive had a maximum range of 1 mile (1.6 km), but range could be extended to 4000 yards (3.7 km) by reducing projectile weight to 200 pounds (100 kg). Maximum muzzle velocity was 800 feet (250 meters) per second. Range could be reduced by releasing less compressed air from the reservoir. Ten shells per gun were carried on board, and 15 shells were fired in 16 minutes 50 seconds during an 1889 test. The shells employed an electrical fuze which could be set to either explode on contact or delayed to explode underwater.