Lyle Gun - History

History

A line-throwing gun is a short-barreled cannon designed to fire a projectile attached to a rope to a boat or victim in distress. Experiments in shooting tethered projectiles dates back to around 1800. A mortar device was credited with saving lives as early as 1850.

One of the first actions of Superintendent Sumner Increase Kimball, the only superintendent of the U.S. Life-Saving Service, was to find a better line-throwing device. Kimball realized he needed the best artillery expertise available, so he engaged the help of the Army Board of Ordnance and in 1877 they assigned David A. Lyle, Captain, U.S.A (1845–1937), a West Point and MIT graduate who began research and testing that resulted in reliable efficient designs. Lyle developed 3 bronze, smooth-bore guns of different sizes and the 2+1⁄₂-inch-bore (64 mm) gun became the USLSS standard line-throwing gun.

Projectiles for the gun were made of cast iron with a wrought iron eye bolt screwed into the base as an attachment point for the shot line. The projectile for the 2+1⁄₂-inch (64 mm) gun was 15+3⁄₄ inches (400 mm) long and weighed 19 pounds (8.6 kg). It was placed into the 24-inch-long (610 mm) gun barrel so the eye bolt with the line attached was sticking out. After firing, the projectile rotated so that the eye bolt and line were trailing. The gun had a large recoil from firing. A standard charge of 1.5 ounces (43 g) of gunpowder would knock the gun back 6 feet (1.8 m). The maximum rescue charge of 8 ounces (230 g) would send the gun flying back even further.

The type of gunpowder used was also critical. It was a variation of black powder,uniform grain size, marketed as Hazard’s Life-Saving Service Powder and DuPont Life-Saving Powder.

Shotline was also just as critical to the accurate operation of the Lyle gun. Hemp line was found to be too brittle. Braided linen was usable, but it was too heavy with sea water after it was fired and had to be dried out before firing again. The best line was waterproofed braided linen. It cut through the air best and provided improved range. New lines were too stiff and were difficult to properly flake (to wind in a pattern so the line could be shot without getting tangled), so a new line needed to be fired several times to make it more flexible for flaking. One of the critical drills of the USLSS crew was flaking the line. If the first shot failed to go over the stranded ship, the line would have to be hauled in, reflaked, and shot again. An efficient flaking crew could minimize the time required to get ready for the second shot. On average, a crewman with two assistants could flake 700 yards (640 m) of line in about 25 minutes.