Reference 
A 
http://www.vikingsword.com/vb/showth...nt+arms+armour
Incredibly this weapon which comprises of two bits of wood and a length of string was like a machine gun when unleashed en masse on an enemy formation on land or aboard ships and was faster to reload and more devastating untill well after the advent of gunpowder. 
I have designed this thread with a short starter as I have some interesting material to add as it rolls out to allow maximum input from members. 
Regards,
Peter Hudson.