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Remora News & Events

Features

August 20, 2014

Tales of divers and gliders and missions at sea

Richard LaPalme,
Team Ocean Volunteer Science Diver,
Gray's Reef National Marine Sanctuary

Wilmington River sunrise from Priest Landing docks.

Wilmington River sunrise from Priest Landing docks.
Photo: Jared Halonen

The warming sun rises over the Skidaway Island harbor on Wednesday, August 20, 2014 with a hint of promise for our NOAA staff and volunteer adventurers. The wind is still blowing strong, whipping the water surface into a rolling white-capped seascape. The project is already two days behind schedule due to the strong winds and heavy seas on Monday and Tuesday, conditions deemed unsafe for the project staff. Today everyone is ready to get to sea, conditions are forecast to improve and the loading and readying of equipment begins as the sun starts to rise. The research vessel's Captain, Todd Recicar anticipates that the still rolling seas will calm enough later in the morning to allow for safe working conditions afloat; so we methodically load gear and work off the checklist.

Todd Recicar explaining the mooring deployment procedure before heading out to sea.

Todd Recicar explaining the mooring deployment procedure before heading out to sea.
Photo: Alison Scott

Today's objective is to deploy an array of underwater acoustic receivers and transmitters in a defined baseline geometry to enable the assessment of the Autonomous Underwater Vehicle (AUV) navigation in the ensuing tidal currents. Tomorrow the Skidaway Institute of Oceanography (SkIO) project research staff will come aboard to deploy and test the AUV. For today NOAA is using the 41-foot R/V Joe Ferguson to ferry divers and array equipment out to the Gray's Reef National Marine Sanctuary to establish a temporary underwater acoustic transmitting and listening sensor array as a navigational test track for the AUV.

Loaded with one-thousand pounds of gear we head out just before eight o'clock. Part of the departure procedures includes a thorough boat safety briefing by the Captain and a project and dive safety review by the Safety Officer and Divemaster LTJG Jared Halonen. Both of these men provide an insightful awareness of the resources at-hand and the risks associated with the day's objective. One by one potential issues are briefed and the associated safe response is described. Your author, a NOAA Science Diver Volunteer, is pleased to be in the company of such skilled and professional mariners and divers.

Twenty minutes away from the dock we are passing Wassaw Island and turn Southeast toward the Sanctuary. The water color is beginning to lighten and turn bluish. Much to my delight, just thirty feet or so off the starboard quarter is a loggerhead sea turtle floating on the surface. I catch a glimpse of its large brownish shell and its fist size head before we are too far away. A sea turtle sighting is to me always special and on this early morning headed out for a day's adventure, this sighting was all the better. What a way to get started. Bidding farewell we continued for another hour out to our first project site.

Deploying the ADCP to measure the water's current velocity.

Deploying the ADCP to measure the water's current velocity.
Photo: Alison Scott

Throughout the day we stop at nine project sites to deploy first an underwater current sensor and then eight anchored buoy lines with acoustic receivers and transmitters strapped to the lines. There is an excellent mix of project leadership, camaraderie and adventurous spirit among the staff and crew. The NOAA Chief Scientist for the project is Sarah Fangman, a veteran of many Gray's Reef Sanctuary projects. Her enthusiasm for understanding the marine ecosystem and protecting it is contagious. I have the pleasure of diving with Ms. Fangman on the day's first dive to verify that the current sensor has been properly deployed and is sitting upright on the seabed.

DIVE, DIVE, DIVE!

DIVE, DIVE, DIVE!
Photo: Alison Scott

Normally I'd be reaching for my second cup of coffee at this time of the morning, but today we are suited up and standing at the stern of the boat awaiting the safety clearance and the release to "DIVE, DIVE, DIVE." The simultaneous splash of two divers hitting the water gets the crew's attention and we signal a safe entry and begin our descent to the seabed. Wow, the water clarity is fantastic, much better than we'd been led to expect from recent condition reports. As we slowly descend the sixty eight feet to the bottom the water is very clear and the bottom is coming into view quickly. Adjusting our buoyancy, maintaining buddy contact we are just above the current sensor. A perfect deployment. It sits upright on the sandy bottom. We photograph it, release the deployment line and look around for potential sea life.

Out in the field of rippled sand there's not much swimming around so we begin our ascent to twenty feet and a three minute safety stop. As the timer runs down, out of the mists I can see a shape growing in size and approaching us as we hang in the water column. A three foot Cobia makes its way right over to us and passes within feet of our legs. He is a beautiful specimen. Sleek steel gray with a characteristic scalloped dorsal fin in full view. He weaves back and forth checking us out carefully. After several passes he vanishes as he appeared. Exhilarating is how I'd describe it. You can't be anything but awed by the power and beauty of such a creature, especially when it is an arm's length from you.

With two big animal sightings and the days just begun, can it get more fun?

Author Richard LaPalme securing a receiver to a buoy line.

Author Richard LaPalme securing a receiver to a buoy line.
Photo: Sarah Fangman

The boat crew, sanctuary staff and volunteers carefully work on-deck throughout the day to deploy the eight instrumented anchored buoy lines. The boat crew has devised a well planned and safe strategy for handling the concrete anchor blocks, connecting line and buoys. Personnel safety was the first and foremost handling criteria throughout the procedure. Recording of the GPS drop coordinates was meticulously performed for each anchor drop. Each drop required the coordinated actions of five crew members distributed on deck. Each drop was perfectly executed. A result of careful NOAA team planning and leadership execution.

As the day heats up, progress is steady and the crew enjoys a variety of snacks and sandwiches. The dive teams rotate among five divers giving each team plenty of dive excitement and topside rest. On my fourth dive, around three o'clock in the afternoon, a rambunctious remora becomes very interested in my dive buddy's fins and begins making repeated approaches as if to attach itself to the fin's flat surface. Similar to attaching itself to their more usual host, a local shark. We watched in amusement for a few minutes as the two foot long "buddy" swept back and forth pointing his dorsal fin sucker-organ towards our fins. Realizing that attachment was not going to happen the remora heads off to find another more willing host. We surface with anchor and instruments properly set and another great story.

The team continues doggedly at the task of setting the instrumentation array. We complete the day's objectives, head back to the harbor, unload the gear and clean-up, getting ready for tomorrow's objectives. It has been an exciting, learning and rewarding day volunteering in the sanctuary. I'm back at my apartment twelve hours after I left it this morning. Tired, enthusiastic about the sanctuary and grateful to be a part of NOAA's Team Ocean volunteer science divers, I head off for a hot shower, dinner and some much needed rest. Tomorrow's a big day.

Thursday morning is a beautiful, picture perfect Georgia day. The inland heat index promises to approach 106. The sea conditions are turning calm and the sea breeze is dying. It is looking like a wonderful day to be at-sea and under the sea.

The team carefully loading the AUV onto the R/V Joe Ferguson.

The team carefully loading the AUV onto the R/V Joe Ferguson.
Photo: Sarah Fangman

Professor Catherine Edwards arrives at the dock with two doctoral candidates Sungjin Cho and Dongsik Chang. They have a truck full of gear including the six-foot long bright yellow AUV on its hand truck come launcher rail. Everyone lends a hand and the gear is quickly carried down the steeply-sloping gangway. The AUV is gently wrestled onto the rear deck, as if its torpedo shape encouraged extra respect.

The researchers receive the usual thorough safety briefing. We prepare to depart the dock and set out toward the Sanctuary for a day of AUV navigation tests and demonstrations.

Underway the research team is fully engaged in equipment preparations involving the computer controller and AUV final configurations. The NOAA crew and the SkIO researchers interact and mesh seamlessly in a beautiful cooperative choreography. Dr. Edwards efficiently glides amongst her students, the crew and the deck spaces busily organizing the work tasks and mentoring her students. I had the great opportunity to chat with Dr. Edwards about her research and scientific interests. She readily explained her new navigational theory as applied to AUV in layman's terms. Her scientific and scholastic enthusiasm was readily apparent and her eagerness to comprehensively discuss the complete range of the tests and demonstrations was very much appreciated. If the test results are successful, one can see the potential for significant improvements to AUV navigation and the long-term attendant benefits to mankind that efficient remote surveillance of the ocean waters and our fisheries will bring to consumers, fishermen, recreational boaters and scientists.

At about eleven o'clock the NOAA R/V Joe Ferguson arrives at the AUV launch area. The researchers are anxiously going through their final checklist items readying the AUV for launch. The two aluminum fixed blade sweptback wings are attached at the fuselage mid-section with a snap and a click. The final pieces of special synthetic cloth are applied to the hull as a means to reduce remora suction attachments. All systems are tested and verified operational.

The NOAA crew gathers round, wishes the researchers good fortune and all hands assist in moving the AUV launcher to the rear dive platform. Dr. Edwards performs a final visual check, climbs down on the lower external platform reaching over to the launcher and removes the restraining nose ring and nosecone protection plug. On her command the AUV is released and smoothly slides down the launcher rails into the ocean waters beneath. With a splash and a dunk the AUV is free-floating behind the boat. This long sleek bright yellow glider bobbing effortlessly on the surface is a beautiful sight. Its tailfin-mounted embedded antenna provids the communications link with the mission computers on the R/V Joe Ferguson support boat. All eyes are on the floating AUV. It sits trim, upright and ready for the mission. The excitement among the research team and the NOAA crew mounts as the pre-dive checkout commences.

This particular AUV does not have powered propulsion, it uses the local current to propel itself at approximately 80% of the current speed. Through a series of diving and surfacing maneuvers the AUV can propel itself forward and through use of a small tailfin rudder it can control its heading. The AUV onboard instruments include a pitch and roll sensor. Dive and ascent modes are enabled by moving the battery forward or aft of the longitudinal balance point to trim the AUV either down or up. Movement in the water column is achieved by changing the AUV buoyancy through changes in vehicle displacement. This is being accomplished with a motor driven bellows-diaphragm that changes the sea-water volume displaced by the AUV hull.

AUV bobbing at the surface.

AUV bobbing at the surface.
Photo: Richard LaPalme

Before the AUV was launched an external no-fly electrical connector stub was replaced with a special stub that configures the AUV electronics for launch. The researchers stay in contact with the AUV through a variety of communications methods. Short range line-of-sight command, control and data transfer is conducted via a high frequency radio link. Beyond line-of-sight, which is the typical mission mode, the AUV can use its embedded Iridium satellite phone terminal to contact the researchers via their SkIO Internet server which is connected to the Iridium gateway terminal in Hawaii. Also as a fail-safe backup, the AUV contains a "heartbeat" satellite beacon that transmits GPS position and system status data to a Low Earth Orbiting satellite system that continuously monitors the world's oceans for locator beacons of all kinds. Naturally, the radio communications links and GPS receiver function only when the AUV is at the water's surface.

As the pre-dive checkout continues it is determined that the seawater salinity is slightly greater than earlier measurements and the AUV longitudinal trim weight will need to be adjusted. The pair of NOAA divers in the water supporting the launch are given field instruction on how to add weight and how to use the special tools to access the compartment. What ensues is like watching spacewalking astronauts working in space. Slow, deliberate, exacting actions by the NOAA divers are required to ensure that no damage is done to the AUV and most importantly, that no parts or tools are lost to the briny deep. After a few moments of anxious quiet onboard, a cheer is let out for the dive team's success. A first for this team, is performing an in-water AUV modification. Another sign of the close collaboration among the NOAA staff and the SkIO research team.

Dongsik Chang working hard at the computer.

Dongsik Chang working hard at the computer.
Photo: Richard LaPalme

As the hot midday sun reflects upon the brightly colored AUV that sits bobbing in the light surface chop twenty feet from the boat, a final pre-dive check of the AUV trim motor and bellows-diaphragm system is conducted. The NOAA dive team is hovering in the vicinity should they be needed. The R/V Joe Ferguson sits dead in the water awaiting the imminent AUV dive. Dr. Edward's research team is huddled around the computer monitor in the ship's cabin. Commands are being issued from the keyboard. Results are displayed on the screen. Fingers touch the screen and scroll down the columns of numbers. Glances are being exchanged among the research team. The hull displacement system is not responding correctly. The AUV can be seen to be in a nose down trim position but the AUV is not diving. After some additional analysis the team decides that a system malfunction has occurred and decides to scrub the mission. Corrective action will need to wait until the team is back at the SkIO lab and further disassembly and diagnosis can be performed.

Richard packing away a buoy line during his ascent.

Richard packing away a buoy line during his ascent.
Photo: Maya Walton

The AUV is recovered and stowed. A somber mood briefly settles on all present. The opportunity allows us to reflect on the difficult nature of ocean research and the fortitude required to pursue the attainment of ecosystem knowledge. A collegial exchange of understanding and empathy is exchanged among the now integrated team members. It's not long before a brighter mood returns to the researchers as alternate plans are already being formulated.

Your author is most grateful to NOAA Gray's Reef National Marine Sanctuary staff and the Skidaway Institute of Oceanography research team to have been invited to participate in this AUV launch. It has been a fine demonstration of professionalism, dedication to the pursuit of knowledge about our oceans and inter-disciplinary multi-organization team work.


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