A spider crab decides that seismometer deployed by scientists on board the research vessel Thompson is the place to be on the ocean floor. ROV Jason © Woods Hole Oceanographic Institution
“OPB science reporter Jes Burns shares a strange tale of “crabotage” that emerged as scientists aboard the research vessel Thompson tried to answer complicated questions about the Axial Seamount.” Read the whole story.
Alvin’s first Woods Hole dip in nearly ten years. Jayne Doucette © WHOI
On Wednesday, June 29, 2022, human occupied vehicle Alvin submerged for the first time since returning to port for repairs in the fall.
This was a tethered wet test, an opportunity to make sure the sub is ready for diving at sea. “We go through all the systems and make sure they are working,” said Alvin Expedition Leader Randy Holt. “There are things you can’t find out when the sub is dry, so it is ideal to do this while we are still in our home port.”
On the first dive, the only issue was seawater entering a connector on the imaging junction bottle on the sub. The fix: replacing an o-ring. It was a minor issue on the first submersion of a sub that was reassembled from thousands of pieces. Still, the team halted the dive, took the sub out of the water, and made the repair before continuing.
The test attracted a small crowd on the dock. “That’s because of what this sub means to people, and they haven’t seen it in the water here in Woods Hole in nearly ten years,” said Alvin Pilot and Group Manager, Bruce Strickrott. “Alvin is a machine that has the power to inspire.”
Alvin was piloted by Anthony Tarantino and crewed by engineers Rick Sanger and Isaac Vandor for the tests.
Human Occupied Vehicle Alvin is getting ready to set sail on R/V Atlantis in July to resume work to certify the sub’s new maximum dive rating of 6,500 meters (4 miles).
Watch the livestream of the vehicle loading here.
We’ll keep you updated as the trip unfolds with regular blog posts and pictures.
The ROV Jason team on a joint Jason and Sentry expedition to explore the Escanaba Trough in June 2022. Pictured: (L-R standing) Ben Tradd, James Pelowski, Sarah Sergent, Gianna Conroy, Gabrielle Inglis, Chris Judge, Scott McCue, (L-R seated, knee) Megan Bachant, Peter Hall, Amanda Sutherland, and Mario Fernandez.
The Escanaba Trough is about 200 miles off the coast of northern California, according to NOAA’s expedition site. A team of scientists explored the area “in order to characterize the hydrothermal sulfide system within the trough” and to “learn more about the hydrothermal minerals, fluids, and organisms that live near active and inactive hydrothermal settings and explore interactions between marine life, the metal sulfide minerals, and the hydrothermal and oceanic environments enveloping both.”
Read the Field Log and browse the (gorgeous) images the team has posted on Twitter.
Peter Girguis, Harvard University Professor of Organismic and Evolutionary Biology
Hear from Harvard University Professor of Organismic and Evolutionary Biology—and frequent NDSF Vehicle User—on what draws him to study the creatures of the deep sea. See if you can spot all three vehicles—Alvin,Jason, and Sentry. Watch here.
HOV Alvin lead mechanical engineer Fran Elder and R/V Atlantis third mate Kenny Beaver recover the submersible during sea trials in late 2021. (Ken Kostel © WHOI)
When Human Occupied Vehicle Alvin‘s sea trials came to an unexpected halt last November, engineers on Atlantis and at WHOI wasted no time in setting the stage for the sub’s eventual return to operation.
Efforts to identify the cause of damage to Alvin‘s syntactic foam began even before the sub returned to Woods Hole, with regular meetings between engineers at WHOI and members of the Alvin Team on Atlantis convening before the ship was within range of Puerto Rico’s cell network. Those discussions focused on two key themes: What caused the cracking in Alvin‘s syntactic foam around attachment points to the sub’s frame; and what could be done to prevent it from happening in the future.
At first, suspicion centered on the process of recovering the sub, particularly the moment when the sub is brought under tow behind Atlantis. Underwater, the syntactic foam experiences gradual and equal loading on all sides during descent and similarly consistent unloading during ascent. But when the ship takes Alvin under tow, the forces created when the tow line suddenly becomes taught transfer to the sub, causing the titanium frame to flex around the attached foam. Still, the team couldn’t rule out the possibility that the foam was compressing more than anticipated and it was that line of thought that eventually led to the most likely cause: over-constraint of the foam blocks under pressure.
Instead of sailing back with the ship, lead mechanical engineer Fran Elder flew home directly from Puerto Rico so that he could begin working with Don Peters on failure analysis and on design solutions. Peters is a principal engineer at WHOI who headed the team that redesigned Alvin‘s mechanical structures during the 2011-2014 overhaul. He’s also an expert on the performance syntactic foam under high pressure, and he began conducting additional analysis on the sub’s foam blocks in an effort to differentiate between damage that might result from flexing of the frame and that caused by the blocks shrinking.
When Alvin and Atlantis returned home in late November, the Alvin Team first took a much-needed rest. Then they turned to the task of removing the majority of the sub’s foam and fully documenting the damage. What they saw confirmed suspicions that the foam wasn’t being allowed to change shape under pressure. “The stresses caused by shrinking aligned with the damage we saw,” said Elder. ‘It was good evidence we had an over-constraint problem.”
Almost immediately, the team began shipping damaged foam to Engineered Syntactic Systems, which has an accepted method for repairing what turned out to be relatively minor damage. “Foam cracks,” said Elder. “We’ve seen this issue before. Titanium doesn’t shrink, but foam does.
That fundamental difference between foam and frame is difficult to balance. The frame needs to provide rigid support the syntactic foam and other major components of the sub, but the foam needs to be free enough to shrink under pressure (and expand on the way up). The discovery that not all of the sub’s foam showed evidence of damage was telling-blocks on the front of the sub on either side of the personnel sphere (the cheek blocks) and on top of the sphere (the brow) were unscathed and currently remain on the sub. This, said Elder, is likely because they fewer attachment points to the frame and are not as constrained in all dimensions.
Peters and Elder still haven’t completely ruled out the effects of frame flexure, so they’ve continued analyzing both scenarios-frame flex and foam shrinkage-to make sure they’re not overlooking something, but all signs are pointing to the foam being over-constrained. Elder has also begun work on design modifications that will give individual blocks greater freedom to move as they compress. But he has to do so while still remaining within the U.S. Navy’s requirements that the sub’s systems be able to withstand a 2-G vertical load and 1-G loads in the horizontal and transverse directions.
And he has to do so while keeping one eye on the calendar. Atlantis remained at Woods Hole through January, but will soon depart on some general-purpose research expeditions that will last through spring. In May or June, it will return to Woods Hole and a fully repaired Alvin will roll out of its high bay, ready to resume the sea trials and science verification process and, beyond that, to return to science at 6500 meters.
Learn how data collected from NDSF vehicles is moving science forward. Here are some talks featuring our vehicles at the upcoming 2022 Ocean Sciences Meeting.
28 February
CT06 02
12:45pm: C-spec: a deep sea laser spectrometer for measuring the carbon system (dic and pco2), Beckett Colson, MIT-WHOI Joint Program #ROVJason
1 March
DS07 02
10am: Gas sensing in the deep ocean: advancing our ability to chemically explore, Anna Michel, Chief Scientist for Deep Submergence at Woods Hole Oceanographic Institution #ROVJason #AUVSentry
2 March
DS07 03
9:00am: Automated target detection and classification of a wide-area ocean dump site surveyed by unmanned underwater vehicles, Sophia Merrifield, Scripps Institution of Oceanography #ROVJason #AUVSentry
DS08 01
3:30pm: Investigating seafloor venting at the Southern East Pacific Rise using the Sentry AUV, Chris German, WHOI and co-authors #AUVSentry
3:40pm: Plume Raiders—exploring dimensions of submarine volcanism and understanding how it impacts ocean chemistry and productivity, Joseph Resing, University of Washington #AUVSentry
DS07 05
2:40pm: Autonomous experimental design and decision-making for mapping deep sea hydrothermal plumes, Genevieve Elaine Flaspohler, MIT-WHOI Joint Program Student #ROVJason #AUVSentry
2:45pm: Iterative bayesian methods for deep sea hydrothermal plume mapping with autonomous underwater vehicles, Victoria Preston, MIT-WHOI Joint Program Student #ROVJason #AUVSentry
ME11 02
3:45pm: Habitat suitability modeling of deep sea scleractinian coral reefs in the north pacific, Mauricio Silva, Florida State University #AUVSentry
4 March
ME17
9:10am: Importance of chemosynthetic primary production to a recently discovered methane seep coral from the pacific Costa Rican margin, April Stabbins, Temple University #AUVSentry
Talks in this listing mentioned an NDSF vehicle in their OceanSciences abstract, if you are giving a talk that uses data from Alvin, Jason, or Sentry and you don’t see it on this list please email the link to ndsf_info@whoi.edu and we will add it.
Photo by Chris German, ©Woods Hole Oceanographic Institution
WHOI geochemist Chris German helped organize virtual planning sessions recently for AUV Sentry dives during the third of three expeditions to study seismicity along the Gofar transform fault in the eastern Pacific. Joining German, who is a co-principal investigator of the 4CAST GOFAR project, in WHOI’s AVAST (Autonomous Vehicles and Sensor Technology) facility for Sentry dive 621—the eighth of the expedition—were University of Delaware PhD student Melinda Bahruth and Sentry Team member Stefano Suman. During their meeting, the three were able to view and discuss sensor data from Sentry in real-time.
Watch video from a ROV Jason and AUV Sentry expedition on the Scripps-operated R/V Roger Ravelle to the Guaymas Basin the Gulf of California. This trip was lead by Chief Scientist for Deep Submergence Anna Michel and included scientists from Harvard University, Michigan State University, and the Ensenada Center for Scientific Research and Higher Education in Mexico.
An interdisciplinary team of biologists, geologists, chemists and engineers walk you through their work at the site, what’s special about the Guaymas Basin, and the paths they took to careers in ocean science and engineering.
Exploring By The Seat Of Your Pants | Exploring Guaymas Basin Live from R/V Revelle
The team on Roger Revelle took questions live from classrooms around the U.S. and Canada and shared live video from ROV Jason on the seafloor.
Hosted by WHOI | Live from the seafloor in the Gulf of California Part 1 and 2
In Part 1 Chief Scientist Anna Michele describes the goals of the expedition and some of the students describe their work at the site, while live video from ROV Jason shows scenes from the seafloor of active hydrothermal vents in the Guaymas Basin.
In Part 2, students on the expedition play a video (also below) showing some of the people who made the expedition possible and share their experiences on the ship and in their career paths in ocean science and engineering
I don’t usually do this; I don’t usually write for WHOI in the first person. Because what I have to say is not about me, it’s about the scientists and engineers, their work, and what they help us learn about the ocean. That’s what matters day-to-day and so that’s what I write about as objectively as possible. Occasionally I’ll feel brave and throw in a “we” here and there.
But today is different. Almost eleven years to the day after walking onto Atlantis for the first time to cover an Alvin cruise in the Gulf of Mexico, I made my first dive in the sub.
My bad luck with being selected to dive in the years since then had become sort of a running joke. Anytime someone asked me if I’d ever dived, I’d reply that I was the person the chief scientist would turn to at the end of an expedition, with the ship’s engines spooling up and the bow pointed toward our demobilization port, and say, “If we’d had one more dive, you would have gone down.” There’s more truth to that than not. But while I’ve born the disappointment with good humor (again, it’s not about me), not being able to dive always been a little bit of a sore spot that I’ve salved with other work. I wrote, I photographed, I interviewed, I put in late nights and early mornings. As a result, I have hundreds, if not thousands of images (some good, most mediocre) of everything that happens on the ship and in the water to get Alvin down to the seafloor and back each day. But the period in between deployment and recovery has always been a story for someone else tell.
No more.
Today, the choreographed intricacy and intense focus of launch and recovery were for others to watch and for me to experience from inside the sub. Today, when the pilot completed his checks and called up to the Launch Controller to load the sub, I made the climb to the top of the stairs leading to Alvin‘s sail. And I watched from inside the personnel sphere as the hatched closed above me.
Dozens of launches told me what to expect: the hoist and boom out over the water, the preparations by our swimmers to clear lines and confirm our vent valves, the call for final checks and request for permission to dive. But there was something I was completely unprepared for. For nearly 11 years, I’ve seen Alvin as a hulking, 43,000-pound machine. Don’t get me wrong, it’s a wonderful machine, but it’s also something so massive that it requires a 274-foot ship with 24 crew and a skilled team of engineers to move it around the world and to accomplish whatever science might call on it to do. I wasn’t prepared for this sumo wrestler to transform into a ballerina the instant it submerged.
As soon as there was water over its sail, it was as if Alvin breathed a sigh of relief, shook off its bulk and danced. It actually danced. And when we arrived on the seafloor, yes I was amazed to see the view in three dimensions as everyone told me I would be, but at some point I sat back from the porthole and laughed out loud, struck with the joy that Alvin radiated to be home again doing what it was meant to do.
This is a blog post, not a New Yorker essay, so I’ll spare you more prose and go back to being a correspondent for a moment. Bruce, Nick, and I were fortunate to be on Alvin‘s deepest dive ever. We settled on the seafloor at the end of the day and the depth readout clicked over to 5338 meters. We didn’t see much because we were on a mission to get Alvin deep-5000 meters at least, deeper if possible-so we flew high over the seafloor and, at 1 knot, relatively fast for Alvin. We surpassed the former and met the latter goal, so the dive was objectively a success. But at the surface, as you may have read elsewhere, the team found a problem with Alvin‘s syntactic foam that will put further dives on hold while the team sorts things out.
However, this fact does not detract from what is a remarkable achievement. Alvin is in an experimental phase, diving places it has never gone before, and it did so with ease and grace. It also underscores that what this team does is inherently difficult. They may make Alvin dives look easy and successful dives to the deep seafloor a matter of course, but as I once wrote during another expedition, the ocean does not give up its secrets easily. It’s a challenge-a solvable one, but a monumental challenge nonetheless.
What comes next will require long hours and considerable time and effort on the part of a talented and (temporarily) dispirited team. But I have no doubt they will make it right because that is what they do-they solve problems and make difficult tasks appear routine. I’m already seeing signs that they are turning to the challenge at hand, proposing solutions, and working through alternatives. I also have no doubt that Alvin will soon be back dancing across the seafloor because that, too, is what it was meant to do.
-Ken Kostel