It was a project carried out by the Office of Naval Research, to develope a method to launch balloons from the sea surface using small ships.

Launching balloons from ships has many advantages. Bad weather areas can be avoided; the launch position can be chosen with respect to favorable recovery areas, and balloons can be launched in regions which are important from the point of view of the experiment itself. A ship also provides readily available living space, shop facilities and instrument shelters.

The problem with launching balloons from ships is that there has to be enough deck area to properly lay out the balloon material before inflation, as well as to place the payload, launching rig and helium supplies in the most favorable positions. With balloons of million-cubic-foot sizes or larger, only aircraft carriers and some sea plane tenders had decks large enough, which in turn aren't always available for balloon flights.

The Project Wetfoot devised a method to allow the use of a small ship: the balloon was dropped over the fantail into the water with the ship steaming downwind. At inflation when the helium bubble at the end of the balloon becomes large enough to rise from the water's surface and to pick up the balloon train, the drag forces decrease and the ship speeds up until she is going the same speed as the wind. This, in effect, creates a "no wind" condition and the balloon rises clear of the water and stands erect. The water runs off the balloon in a matter of minutes and it's ready for the ascent to the stratosphere.

Successful test launches using this method were performed on Lake Michigan from the USS Lamar, a small patrol craft. Also the technique was tested in heavy seas off the east US coast, by the USS Richard E. Kraus destroyer, facing winds of up to 15 knots.

Allthought these succesful tests, the technique was never fully exploited.

In 2009 a Romanian Aerospace group using balloons as first stage of a rocket intended to use this same launch method, but faced several troubles and failures, that finally lead to abandon the idea.