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Posted at 11:51 AM ET, 08/17/2012

The U.S. Navy FLIP: a radical ship for ocean-atmosphere research

(Scripps Institution of Oceanography)
Imagine while cruising on a friend’s yacht somewhere in the eastern Pacific you catch sight of what appears to be the sinking of a large ship: the bow (front) begins to rise above the waves and stern (back) starts to sink below. Just 30 or so minutes later you are astonished to see the bow section standing vertical some 5-stories above the sea surface and not sinking any further.

So, what in the world could this be?

It’s definitely not a sinking ship, an apparition after too much sun and drink nor an alien space vehicle...

Rather, this strange vessel is the U.S. Navy’s unique, one-of-a-kind oceanographic ship, the FLoating Instrument Platform, colloquially known as FLIP.

While FLIP might seem the latest 21st century advance in ocean science (including ocean/atmosphere interactions), the Office of Naval Research (ONR) and Scripps Institution of Oceanography, which actually operates FLIP, recently celebrated its 50th anniversary of its launch (June, 1962). It was later modernized in 1995.

FLIP is 355 feet in length with a long hollow ballast area towards the rear. As the ballast is flooded, FLIP lives true to its name by pitching backwards until 55 feet of the nose section sticks straight up above the water. In the process the usual 16 personnel aboard (5 crew, 11 scientists) initially standing on the outside decks slowly step onto the bulkheads (walls) which transform into the decks. Throughout FLIP, decks have become walls and walls have become decks or ceilings.

FLIP flips, courtesy Scripps Institution of Oceanography

After an approximately 30-day science mission, compressed air is pumped into the flooded ballast tanks and reverses the process until FLIP returns to its horizontal position.

Think about how the inside furnishings, hanging pictures, closet contents, etc. and you might fare if your house was turned over 90 degrees. Obviously, FLIP is designed to mitigate the topsy-turvy change in orientation by, for example, allowing various items to freely rotate. Also, equipment that can readily be unbolted and moved. Or, in some cases it can be duplicated in both horizontal and vertical positions.

FLIP was initially intended for studying wave heights, water temperature and density, meteorological data, and, most importantly, acoustic signals (propagation of sound waves) so important for identifying and tracking submarines. FLIP is the perfect platform for such studies because its buoyancy characteristics allow it to be virtually immune to disturbances from waves.

FLIP has no engine which even if shut down might create unwanted noise that could interfere with measurements. In this sense, FLIP is not really a ship (must be towed). Rather, it’s more like a huge spar buoy nominally used for oceanographic measurements.

As noted by William Gaines, program manager at Scripps: “In recent times, we’ve done a lot of the marine mammal research because FLIP has the ability to be very quiet and stable in the vertical position. We can place hydrophone arrays far below the surface and put marine mammal observers up top to correlate the signals from the animals to the visual observations.”

FLIP in the horizontal position (Scripps Institution of Oceanography)
In 2010, researchers used FLIP for a set of experiments called High Resolution Air-Sea Interaction project, which measured near surface winds and air temperature, sea temperature and density, and wave action. Data such as this is necessary for improving simulation in weather forecast models of transfer of heat, moisture, and momentum (energy of wave/atmosphere motion). According to Linwood Vincent , a recently retired ONR division director who managed several projects that employed the FLIP: “It would be very difficult to conduct these studies on a rocking ship.”

More recently and likely into the indefinite future, FLIP continues to offer researchers the ideal platform for investigations that include monitoring everything from whale calls to subsurface earthquakes.

Related links:

Flipping for Science

FLIP marine research vessel ( informative video)

By  |  11:51 AM ET, 08/17/2012

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