Subsea Vehicles
Inside WHOI
Submersible Technology Advances at Speed at WHOI
Woods Hole Oceanographic Institution is legendary for its subsea exploration and discovery. Central to its work are its fleet of crewed and uncrewed submersibles, and technological evolution is central to its missions. Andy Bowen, an ocean engineer and director of the National Deep Submergence Lab, and Bruce Strickrott, an Alvin Pilot, discuss the WHOI fleet.
By Greg Trauthwein, Editor
AUV Sentry underwater operating near the surface.
Photo by Luis Lamar/ © Woods Hole Oceanographic InstitutionThis audience knows the WHOI brand very well, can you give us an overview of the WHOI submersible fleet today?
ANDY BOWEN: What we're seeing is a more diverse ecosystem of access. The default has been human-occupied submersible exploration of the deep ocean, and Alvin has been an incredibly productive tool for that. But increasingly, we're adding tools that broaden the footprint and the presence in the deep ocean: tethered vehicles or autonomous systems, enabling a more diverse, broader group of researchers to have access into the deep ocean.
BRUCE STRICKROTT: Alvin is a submersible that takes people in a sphere wrapped inside of a submarine. And whereas Andy was talking about expanding the ability to join the experience, one thing about Alvin is we compartmentalize most of the experience inside the sphere on a day-to-day dive schedule. The technology that's used in the sub has leveraged off a lot of the technology that's being developed by some of the other (uncrewed) vehicles, making for a much more capable submersible. We use both technologies (crewed and uncrewed) on a cruise with the scientists, running the submarine in the daytime and the autonomous vehicle in the evening to double the impact of the technology for the science.
When you look strictly at the submersible assets, can you discuss how the vehicles themselves are evolving within WHOI, and today work together to advance deep sea research?
BOWEN: You’re hitting on a really important point, Greg: the coordination of assets, the collaboration between the technology, is a key aspect. The ability to work with an increasingly diverse set of tools, some of which might be operating in real time and in partnership with the submersible, I think that's a key area of development. So that the information that's being discovered by a robot, for example, can be shared in real time with the human explorers. And that's extremely exciting, I think, to the extent that we're taking the human exploration and amplifying it.
Director of the
National Deep Submergence Lab, WHOI
STRICKROTT: When I started, most of the navigation was ranges and bearings. We used primitive beacons that we would range off of and a lot of it was ‘out the window.’ We still do a lot of that, but recently we installed an inertial navigation system that was developed by WHOI engineer Stefano Suman. That was generated initially for the AUV Sentry and it ported into the submarine very well. Where we used to kind of dead reckon our way around, now we know exactly where we are relative to an initial GPS fix.
When you look at the submersible market today, what do you see as the main drivers? In that I mean, what are the demands that are driving development or tech development in your R&D centers today?
BOWEN: Some of the most important aspects are not ‘glamorous’ and are more about infrastructure, if you want to look at it that way. That has to do with communications and positioning. Improvements with regard to sensing and the increasing sophistication that robots are able to exhibit, vis-a-vis autonomy, all those elements combine together to make really important steps forward.
So, for example, an autonomous vehicle that has adaptive sampling strategies that might be used to sense things in the water column, to follow animals, for example, and then be able to report those through the use of acoustic communications in a very sparse or parsimonious way so that you can actually exploit the presence of that vehicle to redirect its activities. These are aspects that are really revolutionizing the exploration process, I think, because going there is difficult, it's an arduous and risky undertaking. And one of the things that's most important to us and our sponsors and those we serve is to make maximum use out of being there. Technologies really help in that regard.
AUV sentry operating below the water surface.
Alvin launches to a dive in the Puerto Rico Trench as part of the sub’s science verification expedition.
The human-occupied vehicle (HOV) Alvin at the surface after a dive, during its recent science verification expedition at locations on the Puerto Rico Trench and Mid-Cayman Rise in the Atlantic. The world’s most productive sub was certified to dive to a maximum depth of 6,500 meters (4 miles). The new maximum depth puts roughly 99% of the global seafloor in reach—including the lower Abyssal Zone and the upper Hadal Zone, home to ultra-high-temperature hydrothermal vents, newly discovered volcanic processes, untold mineral resources, and much more. This will also give the science community an unprecedented opportunity to visit a critically under-studied part of the planet that plays a role in carbon and nutrient cycling and that will offer a view into how life might be evolved to conditions in oceans beyond Earth.
What do you see as the key enabling technologies today, either developing or what you see coming soon, that will or are providing your submersibles the ability to do their jobs more effectively and more efficiently?
BOWEN: Well, that's a challenging question to answer and to not be tempted to go off into the weeds and sort of look at bundling these technologies together. I think for us, the ever-improving ability to communicate at high bandwidths and very low latencies through the use of low Earth orbiting satellites provides us with distant and reliable communications, obviously to our research vessels, but also to the platforms that might be exploring the undersea. And while of course those high-band communications are not possible underwater, it's utilizing these and the evolution of improved acoustic communications, as well as the intelligence, if you will, of those systems operating underwater, that is really revolutionizing and providing us with really rapid improvement in our capabilities to explore the ocean.
STRICKROTT: To add to what Andy said, the ability to have remote support for operations at sea. There's a lot of work looking at reducing crew sizes out at sea because it’s an expensive endeavor. But [with high bandwidth communications] you don't have to bring everybody with you because you have the ability to communicate with the folks on shore that can log into the systems and work on them.
Alvin Pilot, WHOI
BOWEN: To echo and emphasize, the early days of submersible exploration with white-scarved submersible pilots and observers was an incredibly exclusive exercise. There were only a few people that were ever able to explore the deep ocean. And I think that we are seeing advances in telepresence communications, machine autonomy and it's really creating a much more inclusive opportunity. So, some of our work involves scientists and even operators who are shore based and maybe distributed geographically. And that's making for a process that is vastly different than a historical norm.
STRICKROTT: For a while, people were arguing that this kind of capability would render sending people [out to sea] obsolete. I actually think it's done the opposite. It's added value to sending people out to do work. It's critical to send people to go down and see areas that are mapped and discovered. But the one technology isn't mutually exclusive of the other.
Can you discuss one project in detail, either recently completed or ongoing, that you believe really highlight the value of the submersibles in the quest to advance deep sea research?
BOWEN: I think one of the things that is satisfying is to develop some technology for high latitude work, and in particular working in a polar setting, whether it be on the sea floor at 87 degrees North in an icebound environment, or providing the opportunity to access, say, under glacial ice tongues for instance. That is in many ways an analog for exploring at the very extreme parts of the universe, if you want to go that far, looking at icebound parts of our solar system and potentially beyond. But it's really an extreme application of the technology. It's incredibly high risk. I can attest to that personally in terms of waiting for a vehicle to come up over the span of several days after it stopped working. And luckily we were able to retrieve it. But that's at the very periphery, I think, of what's possible today.
STRICKROTT: I could tell you a million stories about what I've seen by just taking people out to sea and enabling them to do their research; that experience changes people's lives [and allows them to share that experience with others].
I think the big thing that I've seen is how these technologies enable people to discover, or to think of problems in a different way. All of the advances that are happening will continue to open opportunities for people to think outside the box relative to global scale problem solving. And I think that's where the blue economy is built around.