Greek fire

Has anybody got a reliable formula for making Greek fire (naptha)? My historical reenactment society is staging a sea battle with miniature galleys on an artificial lake as part of an entertainment hosted by a wealthy golf estate developer, and I don't want to shirk on the details.

ingredients:
1 packet raspberry jelly crystals.
petroleum to taste.

make up the jelly, using petroleum instead of water.
place jelly in wads in miniature catapults, and set alight.
open fire!

warning: use of jelly crystals of flavours other than raspberry can be exceedingly dangerous!