In the final paper, sway stabilization systems on ships are described. There are different ways to stabilize sway, but the main division is into active and passive stabilizers. The difference between active and passive stabilizers is that passive stabilizers do not need any additional energy or control system to work, while active stabilizers are more technologically advanced and have different electronic systems that record the movement of the ship and predict exciting moments. The paper focuses on sway stabilizers for cruise ships. Most often, passenger ships use stabilization systems that fall under the active system. These are stabilizer wings, and there are four types of such stabilizers that are suitable for all conditions and needs of the ship. The emphasis is on two cruise ships, "Crystal Serenity" and "Harmony of the Seas", and the stabilization systems of those two ships are described and compared. The Norwegian Classification Society (DNV) has summarized most of the failures and the reasons why the failures occur. Although today's stabilization systems are sophisticated and technologically developed, some malfunctions and technical difficulties of the system cannot be predicted or prevented. Therefore, the paper deals with some of the malfunctions that occur in practice, and the ways in which such cases are serviced.