Passive Anti-Roll Tanks

Reduction of roll by means of passive tanks has been tried, on and off, for over 80 years. A description of sorne of the pioneer installations included. Most of the available literature is on the subject of U-shaped tanks. This design data sheet shows present design procedure for tanks which are approximately "H" shaped or rectangular in plan view, and which have nozzles of a variety of shapes port and starboard. The method is still somewhat empirical, since all the testing to determine the effects of simplifications and limitations in theory is not complete. The method here is an extension of the U-shaped tank theory, for which comprehensive technical discussion is available. Before proceeding further, it should be realized that the static or damaged stability of the ship will be reduced by the free surface in the tanks. Section 9290-4-d-7 provides a method of estimating this effect.