Corvus

[Praefectusclassis]

Have you looked at Wallinga's proposal of the tackle around the base of the corvus (p.59ff)? He proposes that the slot in the bridge itself combined with a tackle & block system + the crew manning the bridge could ensure a proper recoil of the bridge. And who knows, perhaps the Roman ship would attempt to back water when the Carthaginians got very close. Moving in the same direction as the attacker would diminish the shock.