How do cruise ships maintain stability in open waters?

There are also ballast tanks, containing water that can be pumped from one end of the ship to the other, and from port to starboard, to maintain stability. Now, the physics. A cruise ship displaces an amount of water equivalent to its own mass. read more

Modern cruise ships are very wide, and beam increases stability. Also, the superstructure is made of lightweight materials (high strength steel, aluminium) and has large open spaces while the hull is made of thicker steel and contains heavy machinery, fuel tanks etc. read more

and Why Mega Cruise Ships Are Unsafe. They have shallow, but wide, bottom surfaces. Either they have small keel surfaces, or they are able to pull the keel inside the ship, because the draught in my city port is fairly shallow and yet they were able to get well inside the harbor. read more