A passive stabilizer tank is basically a vessel interior space comprised between the sides, two indoor and two transverse bulkheads, with a specific internal configuration and containing a certain amount of fluid, usually seawater. Its purpose is to reduce the ship roll motion. For this to occur optimally, i.e., for maximum reduction of roll motion, It is necessary to design correctly.
Designing a passive stabilizer tank consists, on the one hand, to establish the best internal geometry, according to the design limitations imposed: tank location on the vessel, maximum dimensions, or throughway therethrough, etc. And, on the other hand, define, depending on sea conditions and characteristics of the ship's, amounts of water to contain the tank. It also works on numerical simulation techniques to the design of these tanks.