The FLoating Instrument Platform (FLIP) is a naval research station designed in 1962. It is towed horizontally to open water then flips vertically to provide a stable platform mostly immune to wave action.
The tilting is actioned by directing water into ballast tanks. The position is reversed by sending compressed air in the tanks. Because the bulkhead becomes the deck, the FLIP has rooms with doors mounted on the floor, portholes in the ceiling, and sinks and toilets mounted for both configurations.
Developed during the cold war, it continues to provide a uniquely stable platform for research missions that include ocean acoustics, marine mammal studies, geophysics, meteorology, physical oceanography, and laser propagation experiments.