by Chief Petty Officer (SW/AW) David Rush, USN
In a first for the U.S. Navy, an underwater glider was launched with the aid of Navy divers from the Dry Deck Shelter onboard USS Buffalo (SSN-715) on Nov. 14.
The glider is a uniquely mobile network component capable of moving to specific locations and depths, occupying controlled spatial and temporal grids. Driven in a saw tooth vertical profile by variable buoyancy, the glider moves horizontally and vertically.
It gathers various information including seawater temperature, salinity, water clarity, and ocean current speeds. The information is transmitted on a predetermined interval when it surfaces, to computers via satellite phone. Data is collected on compact flash cards, just like the ones used for digital cameras.
Named after Joshua Slocum, the first man to single-handedly sail around the world, the Slocum glider looks like a mini-submarine. It is battery powered and has removable wings and a controllable rudder.
Lt. Cmdr. Patrick Cross, COMSUBPAC Force Oceanographer, said the information that this type of device provides is invaluable to the Navy. “Our interest in the Submarine Force has been to use these to characterize the ocean. They’re equipped with sensors that can give us salinity and temperature versus depth, and from that we can get sound speeds [rate at which sound from a source travels through water]. We can feed that data into our MODAS [Modular Ocean Data Assimilation System], run by the Naval Oceanographic Office, and that provides a picture that we provide to our submarines,” said Cross.
As for what the information means to those assets below and above the ocean, Cross added that it paints a picture that can be used to their advantage. “It’s basically a three dimensional depiction of ocean conditions that is used in tactical decision aides to determine sonar performance,” said Lt. Cmdr. Cross.
Lt. Cmdr. Cross said that the gliders are an easy and effective way to gather important data. “The gliders are a great way to have a persistent sensor out there to continuously feed us data on what the ocean is doing. Then we can feed that to our shore-based computer models and get a better picture of the ocean. We can give that information to all tactical assets, not just submarines but anyone involved in ASW.”
Lt. Cmdr. Cross added that the gliders have demonstrated their capability in various exercises. “We have had incremental success since we began using them in exercises, including a glider in RIMPAC ’04. It did a great job of demonstrating the technology.
Retrieving a glider via submarine is a
logical next step. “One of the future
exercises we hope to do is recover a glider onboard a submarine, demonstrating both deployment and recovery. We would locate the glider via GPS and divers would retrieve it and bring it aboard,” Lt. Cmdr. Cross concluded.
Webb Research Vice President Clayton Jones said the launch was an important step in the right direction. “This is a milestone. It’s the first time we have deployed a glider from a DDS (Dry Deck Shelter). This program will spark interest in those who are pursuing this kind of technology. Frequently you know the areas where you want to work in, so you can get this in there and get an environmental assessment without anybody in harms way,” said Jones.
The gliders are relatively inexpensive, easy to reconfigure for various missions, and have a long life span with minimal maintenance. When new batteries are required they can simply be replaced and the glider can be put back in the water again.
The recent test involved inserting the glider into the water from the DDS onboard Buffalo and then letting it gather and transmit information for five days in an area off the Southwest coast of Oahu, Hawaii.
Jones, along with Lt. Cmdr. Cross and Elizabeth Creed, Senior Scientist, Oasis Inc., departed Pearl Harbor Nov. 18, on a torpedo recovery boat to retrieve the glider.
They used the GPS coordinates sent from the glider to find its location, and upon surfacing, Creed commanded the glider via computer to remain on the surface.
According to Creed, the event went very well. “I got this one ready to operate and have been compiling the data for the last week. Things have gone extremely well. Many milestones have been met and everything we have set out to do was accomplished, so it has been very successful,” he said.
Chief Petty Officer Rush serves in the COMSUBPAC Public Affairs Office in Pearl Harbor, Hawaii.