SILLY QUESTIONS

This may be a silly question, but why don't they have air bags on cruise ships?  I'm talking about a huge air bag running the length of the ship on both sides that would explode out of a compartment just below the main deck and inflate with air and stay inflated.  I know it could be done and I think it wouldn't be too expensive.  It would take a huge bag.   It could inflate the same way rafts automatically inflate.  Even if it couldn't support the weight of the whole ship, it could help keep it upright.  It might even be deployed in rough seas to reduce rocking of the ship.  It would work manually on a trigger by the crew.  What do you think?
:-)