Siege Draft:Combat - Siege Engines and Structures

Siege Engines and Structures

Types of siege devices

There are two types of siege devices:

• active siege engines
• passive siege structures.

Siege engines

1. To avoid confusion, siege engines are defined as those designed to deliver ammunition larger than small arms ammunition.
2. Siege engines are broken down into two categories.
   1. Type A engines are designed to deliver large ammunition to a range between 37 and 74 metres.
      1. Type A engines can use all approved ammunition classes.
   2. Type B engines are designed to deliver small siege ammunition to a range between 37 and 74 metres.
      1. Type B engines are not allowed to use anything larger than small siege ammunition.
3. Any device not designed to deliver these types of ammunition is not considered a siege engine, and unless acceptable for use for combat archery, is not usable.
   1. Man-powered trebuchets are considered Type B engines and must meet the requirements stated, with the exception that they must not be required to have a mechanical release or cocking device.
      1. These engines may fire up to 2 small siege projectiles, or 2–8 small arms projectiles, per shot.

Siege structures

Siege structures, such as towers or ramps, are defined as devices when they are used to support personnel but are not fitted with active weaponry.

Siege engine regulations

General

1. Engines and their projectiles must be inspected by a siege marshal before being used at that event and after any modifications are made to the engine during the course of an event.
2. All engines must not be able to shoot more than 74 metres. This is especially important in direct-fire weapons, where range greater than this often results in safety concerns involving extreme minimum-range impact.
3. Direct-fire engines must not be discharged against personnel within a range of 10 metres.
4. Engines must not be discharged while any non-crew person is within 1.5 metres of the travel path of moving parts (e.g., a trebuchet must not be discharged while a fighter is standing anywhere in the path of the arm, front or back).
5. Engines must be equipped with a safety device sufficient to prevent accidental firing if they are to be relocated while cocked.
   1. Any engine without such a device is only allowed to be relocated while un-cocked.
6. Except for man-powered trebuchets, all siege engines must be fitted with an appropriate mechanical trigger mechanism that must be used for every shot.
7. Cannons or any replica of cannons are not allowed in SCA combat.
   1. Engines may not use compressed or ignited gases or liquids or combusting materials of any kind to power projectiles.
8. Builders should attempt to visually and functionally recreate period siege engines.
   1. Engines must be powered in a manner functionally consistent with their period counterparts.
   2. When period power methods are unsafe or not feasible, alternative sources of power may be used.
9. Engines must be durable enough to survive the rigours of combat and, while they should not be struck with hand weapons, should withstand either being struck with a full-force blow or being run into by a combatant.
10. All engines must be free-standing and may not use an operator as part of their support structure. Operators are not included in measuring the footprint of an engine.
11. Siege engines must not have any bolts, or other projections which may reasonably be expected to contact persons if they fall on the engine, extend more than 1.3cm into a legal face grill.
    1. Any items such as this must be covered with sufficient rigid material, a tennis ball, or a suitable rubber stopper, to prevent them from entering a legal face grill more than 1.3cm.
    2. Triggers, release hooks, or other firing mechanism components that would not normally be in a position that could cause injury should someone accidently fall on the engine, are exempt from this.
12. All siege engines and structures must be labelled for the purpose of identification in line with the requirements for arrows.

Siege engine materials

Any material approved for use in devices on the battlefield is allowed to be used in the construction of engines, provided that the materials are sufficient to ensure the safety of the engine. For safety, the following materials have special requirements:

Turnbuckles and eye bolts

When used in or attached to the source of power for an engine, these items must be rated to withstand 150% of the forces produced (e.g., if the cable attached to a turnbuckle will support 45 kilograms of tension, the turnbuckle is be rated at 67.5 kilograms static load). Hardware store and home centre hardware is often of low quality and rating, while aircraft or marine hardware is generally more appropriate.

Steel cable

While steel cable is useful for such functions as safety-tying a throwing arm, it must not be used as a bowstring for any type of siege engine.

All softwoods and non-laminated hardwoods

1. When used as the throwing arm for a catapult, trebuchet, or the bow arms of a torsion ballista, they must be secured against breakage with a minimum of glue-soaked sisal or jute cord wrapping (5 centimetre wraps every 15 centimetres) over a section of rope glued along the full length of the arm. This should keep the arm from leaving the engine should it break.
   1. It is strongly recommended that all arms be wrapped in this manner, regardless of material used.
2. When used as the support for the main pivot axle(s) of a catapult, trebuchet, or torsion ballista, a minimum of two layers of wood, glued together with alternating grain directions, must be used in order to avoid operating stresses causing a separation of the support wood along the grain.
   1. Using a structural metal plate through-bolted onto a single layer wooden timber is also an acceptable construction method if the axle passes through the metal plate.

Type A engines

Type A engines must:

1. Have a minimum footprint of 1.67 square meters (18 square feet).
2. Be able to deliver a large siege missile at least 37 meters (40 yards).
3. Have a mechanical cocking device, such as a winch or windlass and trigger and are not allowed to be cocked by hand.
4. Have a minimum crew of 3 people.
   1. If crew size falls below minimum, the engine must not be operated.
5. Be able to fire 1 large siege projectile, or up to 5 small siege projectiles, or 2-20 small arms projectiles, per shot.

Type B engines

Type B engines must:

1. Have a minimum footprint of 1.1 square meters (12 square feet).
2. Be able to deliver a small siege missile at least 37 meters (40 yards).
3. Have a mechanical cocking device, such as a winch or windlass and trigger and are not allowed to be cocked by hand.
   1. Man powered trebuchets are exempt from this requirement.
4. Have a minimum crew of 2 people.
   1. If crew size fall below minimum, the engine must not be operated.
5. Be able to fire 1 small siege projectile, or 2-4 small arms projectiles, per shot.

Siege structures

1. Siege structures must:
   1. Be able to support 135 kilograms for every 0.37 square metres of platform area.
   2. Be equipped with railings or walls at least 0.91 metres tall and able to support 45 kilograms per 31 centimetres of railing length if the platform is more than 1 metre from the ground.
   3. Be structurally stable (e.g., a wheeled siege tower should have a base big enough and wheels large enough to safely carry crew over the terrain of the field).
2. Battering rams and battering structures are allowed for use against authorised buildings and siege structures.
   1. Using a battering ram against a human target is expressly forbidden.
   2. Battering rams must be durable enough to withstand repeated impacts and light enough to be safe when carried or if dropped.
3. Siege structures that have a platform must have a base with a width and depth equal to or greater than 80% of the platform height.
   1. The platform may not be larger than the base, and may not extend past the base footprint in any direction.
   2. Structures that have a platform height of over 2.7 metres from standing surface to ground, must not have a platform that exceeds 75% of the base dimensions. For example, a tower that has a platform height of 3 metres must have a base that is no less than 2.4 metres in either direction. Additionally the platform dimensions are not allowed to exceed 75% of the base dimensions (e.g. a platform with an 2.4m x 2.4m base could only have a 1.8m x 1.8m platform).
4. Siege structures must not be made from industrial scaffolding, as it is not designed for the applications in which SCA combat operates.