help destroy catapults

[ExCaliber]

for somereason every time i try to destroy a catapults i can't this is a screen shot of what i mean
http://imgur.com/kEu4SM1
http://imgur.com/w1aVHat
as well i pre ordered the game but i didnt get anydlc?

[PiccoloDom]

check dis out bro https://www.youtube.com/watch?v=GNEbBhcIbBo

[Gandroid]

There's a small back panel you can rip off with your vehicle's harpoon that exposes fuel tanks. Then you can use your thundapoon on them.