Catapult (weapon)

Catapults, also onagers, are ballistic siege engines designed to hurl projectiles using stored mechanical energy. These devices consist of a sturdy wooden frame supporting a lifted crossbar. A vertical throwing arm, attached to the frame by a bundle of twisted rope, sinew, or hair, acts as the primary mechanism for propulsion. When the arm is drawn down by winches and locked into place, tension is stored within the bundle. Upon release, the arm springs forward with force, striking the crossbar, and flinging the projectile outward. To reduce wear and absorb impact, the crossbar is often padded with unshorn sheepskin or similar materials.

The throwing arm features a cup or sling to accommodate various types of ammunition. In addition to large stones, projectiles may include incendiary pots, bundles of flammable material, or diseased carcasses meant to spread sickness within enemy ranks. Heads of executed prisoners or spies are sometimes used as a form of psychological warfare. While catapults can launch a variety of objects, they lack the power to propel large living beings, including human bodies, unless they have been significantly reduced in mass, such as through dismemberment.

Catapults are employed both as offensive and defensive siege engines. They are commonly placed atop fortifications to repel besiegers and on ships for use in naval engagements, where they can launch burning projectiles to set enemy vessels alight. When fired over land, stone or iron projectiles may "skip" upon impact with hard surfaces, potentially injuring multiple targets within a group. Alternatively, shots made of fragmented stone, crude masonry, or brittle materials will shatter upon impact, generating deadly shrapnel that can wound nearby combatants.

Loading and Firing

The time required for loading a catapult depends on the strength and coordination of the crew. Resetting the throwing arm, winching it down to store tension and loading the projectile must be done each time the device is fired. The table shows both the minimum number of crew for each device, as well as the best possible effective crew. For a heavy catapult, the minimum is 3 persons; the most effective crew, however, would be 5 persons. Likewise, these numbers are also given for the light catapult.

When loading the heavy catapult with a minimum crew, a random number is thrown to determine if the loading process requires 5 or 6 rounds. If the crew is effective, then the roll determines whether this took 3 or 4 rounds. Again, a likewise expression is used to determine the spread of time that a light catapult requires.

Once the engine is loaded, it requires one combat round to fire; this includes the initial resetting of the engine. This ensures that while firing is relatively quick, the bulk of the effort remains in the loading and resetting phase. It also prevents the weapon from feeling too overpowered by keeping its rate of fire in check.

Construction

As a rough estimate, building a catapult will require 1 man hour per 13 lbs. of constructed material. By this reckoning, a standard heavy catapult would require about 115 hours, so that a four-man crew could build one from existing raw materials in about four days. Obtaining those raw materials could take longer. The principle construction is of hardwood, with approximately 100 ft. of rope to provide the necessary torsion. No metal is used, as the engine is constructed with wooden pegs.

Aspect	Heavy Catapult	Light Catapult
Weight (lbs)	1,500	600
Crew minimum/effective	3/5	2/4
Loading Time poor/good	5-6/3-4	3-5/2-3
Range	320 ft.	260 ft.
Range adjustment	short (9-16) medium (17-30) long (31-64)	short (6-13) medium (14-24) long (25-52)
Projectile weight (lbs)	14	10
Damage (hit points)	3-36	3-30
Rate of Fire (rounds)	5	4
Hardpoint cost (tons)	40	20

See Also,
Combat
Hardpoint
Naval Combat
Siege Weapon-making I