not all of them are tackles. cannon balls are basically when two players are sprinting toward eachother full pace, the tackle in this occasion in done more with the shoulder. the arms are still used but barely. chicken wings is when you wrap the opposition player with there arms, totally preventing them offloading the ball. crocodaile rolls is at the ruck, if your opposition has bridged over the ball and it is hard to simply push him off with conventional rucking what you do is wrap your arms around his torso or chest and roll to either sidepulling and squeezing him as you go, you use your combined weight and strength to roll them off.