Medieval Torsion Catapults

[Koyuncu]

Mardi bin Ali al-Tarsusi, the 12th century Arab author, describes torsion powered bolt-firing artillery having skeins made of a mixture of silk and horsehair.

I already noted that too.

In the book Medieval Siege Weapons (2): Byzantium, the Islamic World and India AD 476-1526, David Nicolle, mentions some Arabic espringals using silk skeins in torsion springs. It is probable that this could influence Eastern Roman engineers to use them too.

Here the related part of book; http://books.google.com.tr/books?id=ybcl...on&f=false

Here a detailed description about qaws al ziyar;

The ziyar was a torsion siege weapon. Its twisted ropes or skeins were made of animal tendons, animal hair, or silk. Used from at least the 12th century, it was either single armed or double armed. Saladin's men effectively used ziyars during the siege of Acre in the Third Crusade (1189–92). In the 13th and 14th centuries the ziyar was used in Morocco and was sufficiently small and portable that one single ox cart could carry four siege weapons. It was used to throw stones or semiexplosive incendiary material. The bow ziyar, qaws al-ziyar, could shoot large arrows.

Saladin as prime minister, or vizier, of Ayyubid Egypt commissioned a military treatise by Mardi al-Tarsusi in approximately 1169 that described a gigantic two-armed torsion-powered siege weapon called the qaws al-ziyar and known in Europe as an espringal. According to al-Tarsusi's Tabsirat arbab al-albab fi l-najat fi l-hurub (Instruction of the valiant on prevailing in war), the frame for this weapon was gigantic, over 16 1/2 feet tall. It had strings or skeins of mixed silk and horse hair. The frame was made of unseasoned oak. The draw weight weighed one and a half tons. Even without the windlass, Mardi al-Tarsusi explained that 20 men were needed to pull back its bow string.

From; http://books.google.com.tr/books?id=-Jf5...ar&f=false

Also, I tried to search Three Byzantine Military Treatises by George T. Dennis but failed to find silk torsion springs mentioned in The Anonymous Byzantine Treatise on Strategy. How Dennis F. Sullian get the information about it is unknown.