Lyle gun

A Lyle gun was a line thrower powered by a short-barrelled cannon. It was invented by Captain David A. Lyle, US Army, a graduate of West Point and the Massachusetts Institute of Technology and were used from the late 19th century to 1952, when they were replaced by rockets for throwing lines.
History.
Earlier line thrower designs date back to the late 18th century, with the Manby mortar saving lives as early as 1808 when the crew of a brig was rescued at Yarmouth by the use of the device fired from a carriage gun and supervised by captain George Manby. 
A rocket-based system was also devised by British engineer Henry Trengrouse in 1808.
Sumner Increase Kimball, the first and subsequently only superintendent of the United States Life-Saving Service, wanted to find a better line-throwing device. Kimball engaged the help of the United States Army Board of Ordnance and in 1877 they assigned David A. Lyle (1845–1937), a first lieutenant, who began research and testing that resulted in reliable efficient designs. Lyle developed 3 bronze, smooth-bore guns of different sizes and the 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 gun was long and weighed . It was placed into the 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 of gunpowder would knock the gun back . The maximum rescue charge of 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 of line in about 25 minutes.
Operation.
These line guns are used primarily for shore based rescue operations. The Lyle Gun was hauled to the shoreline usually by U.S.L.L.S. surfmen in specially made beach carts. The iron wheels that supported the cart had wide bands outside the wheel to keep it from sinking into soft sand.
The Surfmen would set up and fire the Lyle gun, aiming over the stranded or wrecked vessel and then pull the line within reach of the victims. The line fired to the ship in distress was a messenger line that was in turn tied to a heavier line, the Tally Board (with instruction in English and French), and a Tail block designed to support the breeches buoy. Once the breeches buoy lines and the Crotch Pole (an A frame) assembled, the survivors could be removed from the vessel by hand hauling the breeches buoy lines.
The Lyle Gun could shoot the projectile about , although in actual rescues the practical range was much less. Rescues at greater distances were to be accomplished by lifeboats.
Manufacturers.
There were about 30 companies who made line-throwing guns from the late 19th century to 1952. Famous names included American Manufacturing, Galbraith, General Ordnance, Naval Company, Sculler and Steward. Production of Lyle Guns ceased in 1952 in favor of line-throwing rockets or pneumatic launchers.
Beach apparatus gear.
The Lyle gun was just one component of the items carried on the beach cart; many other pieces of equipment were crucial to the proper execution of the beach-based rescue. The breeches buoy drill, as it was sometimes called, was practiced by the Keeper and all surfmen every Thursday at 2 pm as per the manual at all stations. Crews that couldn't perform the drill in adequate time faced dismissal from the service. It was the crew's responsibility to maintain each piece of equipment in ship-shape as the safety of the crew and the success of the rescues depended upon it. Other items on the beach apparatus equipment list included: