What keeps these huge cruise ships from tipping over when they get into high seas and storms?

Answers

Metal

Their center of gravity and buoyancy is still set in the water. To picture that see this: https://www.youtube.com/watch?v=a79yUWofnSY

Max Hoopla

Stabilizers.

Greg

Ballast (weight deep in the ship).

Terry

There is a lot of weight below decks to balance the ship. besides the ship is wider than you think to avoid that top heavy feeling.

Den B7

gravity

Adullah M

They call it Equilibrium, or in science of hydraulic Engineer as ,Buoyancy ,since there is stabilizer at the bow of the ships and by using Force Plate Balance to keep its stable or in equilibrium all the time , especially during the high seas and storms.