Slocum Legacy | The One Doller Clock | The Slocum Glider and The Liberdade XRay Submersibles


In the early 1990s, Teledyne Webb Research began field trials of a torpedo-shaped advanced auto-pilot controlled underwater glider. Two decades later, in late 2009, the Scarlet Knight, a Slocum Glider, was the first submersible robot glider to cross the Atlantic, porting at Baiona, Spain, where the Pinta made landfall at the end Columbus’s first voyage to America and the first town in the Old World to hear about the New World.

The Rutgers team that engineered this feat then announced their intention to send a submersible glider on a circumnavigation. Find out more here:

In the summer of 2012, Rutgers University, the New Jersey Department of Environmental Protection and the Federal Environmental Protection Agency launched another Slocum Glider to collect scientific data along the New Jersey coast.

The Slocum Glider is described as:

“… a uniquely mobile network component capable of moving to specific locations and depths and occupying controlled spatial and temporal grids. Driven in a sawtooth vertical profile by variable buoyancy, the glider moves both horizontally and vertically.

The long-range and duration capabilities of Slocum gliders make them ideally suited for subsurface sampling at the regional scale. Carrying a wide variety of sensors, they can be programmed to patrol for weeks at a time, surfacing to transmit their data to shore while downloading new instructions at regular intervals, realizing a substantial cost savings compared to traditional surface ships.” – Teledyne Webb Research,

US Navy and Scripps Institution of Oceanography – Scripps Spray Glider and the Liberdade XRAY Advanced Underwater Glider

Spray is an underwater glider developed under ONR support by Scripps and Woods Hole scientists to provide a small long-range autonomous platform for long-term ocean measurements. The Spray is versatile because it is small enough to be deployed from small boats close to shore while still being able to carry a variety of sensors. Sprays generally operate for several months at a time.


The Liberdade XRay is the largest of all of the underwater gliders (6.1 meter wing span), which is an advantage in terms of hydrodynamic efficiency and space for energy storage and payload and is equipped for autonomous operation. Its payload includes acoustics and electric field sensors, along with acoustic and satellite communications capabilities. It was designed for low-cost acquisition, deployment, and retrieval, as well as greater payload carrying capability, cross-country speed, and horizontal point-to-point transport efficiency than existing gliders.

Objectives of the Liberdade program include designing underwater gliders that can achieve 1–3 knot cruise speeds, a 1200–1500 km range, and the ability to remain on-station up to 6 months in loitering glides at partial buoyancy.

Find out more here: