Rocks & mirror
Encyclopedia of Marine and Energy Technology

Parametric roll prevention system (IPRP)


The anti-heeling system developed by the German company Intering™ to prevent the build-up of parametric rolling in head or following seas. Sea-keeping model tests demonstrate that the system can reduce the risk of parametric disturbance by shifting the critical wave threshold to such high values that the chances of ever encountering such a roll during a vessel service life are extremely low.

A typical example of a complete ship system will include several pairs of U-shaped tanks and pneumatically controlled air valves, plus a control unit with pitch and roll sensors. The controller detects the starting phase of parametric rolling and tunes the tank water period and its damping characteristics by operating the valves according to the actual ship motion.

With the metacentric height reduction of appr. 10%, the system will prevent from excessive parametric rolling in significant wave heights up to approx. 10m event at zero speed.