Seagliders fly through the
water with extremely modest energy requirements
using changes in buoyancy for thrust coupled with a stable,
low-drag, hydrodynamic shape. Designed to operate at depths up to
1000 meters, the hull compresses as it sinks, matching the
compressibility of seawater The autonomous
underwater vehicle (AUV)is the result
of a collaborative effort between APL-UW and the UW School of
Oceanography.
These small, free-swimming vehicles can gather conductivity-temperature-depth (CTD) data from the ocean for months at a time and transmit it to shore in near-real time via satellite data telemetry.
Seagliders make oceanographic measurements traditionally collected by research vessels or moored instruments, but at a fraction of the cost. They can survey along a transect, profile at a fixed location, and can be commanded to alter their sampling strategies throughout a mission.
Seaglider's cylindrical hull is a series of arched anodized aluminum panels separated by ring frames. The hull is surrounded by a fiberglass fairing to give it a low drag shape.
After each dive Seaglider dips its nose to raise its antenna out of the water. It determines its position via GPS, calls in via Iridium data telemetry satellite, uploads the oceanographic data it just collected, then downloads a file complete with any new instructions
Seaglider is 1.8 m long and weighs 52 kg—a size and weight that allow easy launching and recovery by two people from a small boat.
Seaglider can travel at slopes as gentle as 1:5 or as steep as 3:1. At gentle glide slopes the vehicle transits most efficiently, while steeper slopes are used to maintain position and act as a "virtual mooring."