The U.S. Office of Naval Research owns a very strange piece of oceanographic equipment. It’s called the FLoating Instrument Platform (FLIP), conceived and developed by the Marine Physical Laboratory (MPL) at the Scripps Institution of Oceanography, University of California. FLIP isn't a ship, even though researchers live and work on it for weeks at a time while they conduct scientific studies in the open ocean. It is actually a huge specialized buoy. The most unusual thing about this ship is it really flips.

FLIP is 355 feet (108 meters) long with small quarters at the front and a long hollow ballast at the end. When the tanks are filled with air, FLIP floats in its horizontal position. But when they are filled with seawater the lower 300 feet of FLIP sinks under the water and the lighter end rises. When flipped, most of the buoyancy for the platform is provided by water at depths below the influence of surface waves, hence FLIP is a stable platform mostly immune to wave action. At the end of a mission, compressed air is pumped into the ballast tanks in the flooded section and the vessel returns to its horizontal position so it can be towed to a new location.

During the flip, everyone stands on the outside decks. As FLIP flips, the decks slowly become bulkheads and the bulkhead becomes the deck. Most rooms on FLIP have two doors; one to use when horizontal, the other when FLIP is vertical. Some of FLIP's furnishings are built so they can rotate to a new position as FLIP flips. Other equipment must be unbolted and moved. Some things, like tables in the galley (kitchen) and sinks in the washroom, are built twice so one is always in the correct position. The entire flip operation takes twenty-eight minutes. When FLIP stands vertically, it rises more than five stories into the air.

FLIP was created 50 years ago, in 1962, by two Scripps scientists, Drs. Fred Fisher and Fred Spiess, because they needed a more quiet and stable place than a research ship to study how sound waves behave under water. Ships were unsuitable as they bob up and down and roll side to side.

FLIP is designed to study wave height, acoustic signals, water temperature and density, and for the collection of meteorological data. Because of the potential interference with the acoustic instruments, FLIP has no engines or other means of propulsion. It must be towed to open water, where it drifts freely or is anchored. When FLIP is in its vertical position it is both extremely stable and quiet.

Since Drs. Fisher and Spiess completed their first tests, many other important data have been gathered using FLIP. The way water circulates, how storm waves are formed, how seismic waves move, how heat is exchanged between the ocean and the atmosphere, and the sound made underwater by marine animals are just a few of the subjects studied using the amazing FLIP.

Related: The Fantastic Sinking Boat by Julien Berthier

Sources: 1, 2