Correct me if im wrong. But what your talking about is a capsol with a small ball or enlongated object inside, that spins in a direction and manner that will actually neutralize any motion of the larger object/vessel it is mounted on. Correct. These are what they are making near me. They are Large steel ball with smaller balls in side that, approx the size of say basketballs that spin a certain direction that stops the boat from rocking.