Originally Posted by MV Miss Behaving
How does it work? Is it like a seakepper?
These are predecessors to Naiad Stabilizers. This is just the control box that contains relays and a gyro - the brains that run the hydraulic actuators that turn the fins on the stabilizers.
These are long out of production, and while Naiad has new-original-stock (NOS) parts for the mechanical pieces (bearings, bushings, etc), the electrical components are no longer available. The relays could likely be replaced with an off-shelf item, but the gyro cannot be replaced except with a used one such as this one. Given the cost of replacement system starts at about $30k, not a bad spare to have around. Many Hatt's from the 1970s and 1980s have Vospers.