Not the water but a big sling type catapult


Close ups and a couple of re-enactment vids of a perrier in Action HERE

Looks very cool!

Thanks
Whic type is more effective?
Take a traction trebuchet of the same size as a counterweight one, with the same fulcrum Ratio (1 - 4-6) and using the same amount of energy applied to the short end of the fulcrum (in either potential energy of weight, springs or People/horses) and with the same load (the Missile)and with the same ratios applied to secondary fulcrum (the sling) of both devices, then the effect would transmit virtually exactly the same kinetic energy to the Missile.