Floating Instrument Platform—FLIP

One of the most unusual sea-going vessels ever constructed has been helping several generations of researchers uncover the ocean’s secrets for more than five decades.

In early 1962, the U. S. Navy needed a stable research platform to measure the fine details of the ocean, particularly how sound traveled underwater. Inspired by how well a mop floated in choppy water, scientists envisioned a long vessel that would have the stability of a narrow buoyant object.

Several configurations for such a vessel were considered. The final prototype was a unit that could be towed horizontally to a particular spot and then, by flooding its ballast tanks, flip to a vertical position with one end underwater and the other in the air.

The Department of the Navy's Floating Instrument Platform (FLIP)With all furnishings and fittings able to turn, the Navy's Floating Instrument Platform (FLIP) begins the process of transitioning from horizontal to vertical by filling ballast tanks in the stern. The 355-foot research vessel is owned by the Office of Naval Research and operated by the Marine Physical Laboratory at Scripps Institution of Oceanography at the University of California, San Diego.
(U.S. Navy photo by John F. Williams)

The Marine Physical Laboratory at Scripps Institution of Oceanography, under the direction of Fred Spiess, took the lead and created a feasible design for the Floating Instrument Platform (FLIP). Researchers developed the spar buoy shape, size (355 feet), and capabilities of this “one-of-a-kind” research platform. They also conducted painstaking experiments, even testing a tenth-scale operating version in a lake near San Diego.

FLIP was constructed in six months at the Gunderson Brothers yard in Portland, Oregon. The initial cost, funded by the Office of Naval Research (ONR), was less than $600,000 (about $4.7 million in 2016 dollars). After successful testing in Dabob Bay, Washington, FLIP was launched on 22 June and delivered to the Navy on 6 August 1962.

After sea trials, FLIP was towed to San Diego and commenced Pacific operations at Scripps. Its unique capabilities as an ocean measurement platform with very low motion have led to its continued use for more than 50 years and over 400 “flips”—supporting a variety of ONR research initiatives, including long-range sound propagation, thermal structure of the ocean, amplitude and direction of internal waves, marine mammal acoustics, air-sea interaction, and weapon system development.

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