Over the course of 4400 dives, Alvin has done just about everything. Its recovered lost nukes, explored the ruins of the HMS Titanic, and upturned our understanding of the deep sea with the discovery of hydrothermal vents bustling with unimaginable forms of life. But after 48 years of service, the venerable ROV is starting to show its age, and is quickly being eclipsed by newer models.
That's the story, at least, until Alvin gets $US40 million in upgrades and becomes the world's premiere deep submergence vehicle once again.
Alvin is the longest-serving deep submergence vehicle (DSV) on Earth. When it first entered active service in 1964, Alvin was nothing short of revolutionary. Designed as a replacement for earlier, less-mobile bathysphere technologies, the 7m long, 15-tonne manned submersible offered researchers the unprecedented opportunity to explore 4500m below the surface. Its 1.8m diameter personnel sphere offered just enough space to cram in two researchers and a pilot, while a trio of 13 cm-wide viewing ports allowed for at least a bit of scientific rubbernecking. However, as Cindy Van Dover, a former Alvin pilot describes to Nature, "sometimes it was a great view, but often it wasn't, so you'd end up watching a video of what the pilot was doing." And in the past few years, France, Russia, Japan, and China have all fielded research vessels with capabilities exceeding Alvin's. Well, that just won't do.
The Woods Hole Oceanographic Institution (WHOI), operators of the Navy-owned vessel, is currently in the first of a two-phase, $US40 million upgrade to bring Alvin back up to par. This first phase, scheduled to be completed by the end of this year, will include a bigger personnel sphere, cut from 15.5 tons of titanium with 18 per cent more interior space. Three new 18cm viewing ports will join the existing set. Researchers will be able to record more of their dives thanks to the addition of high-output lighting and HD cameras as well as a new work basket that effectively doubles its carrying capacity. Alvin will be more manoeuvrable as well, receiving a new command and control system, stronger thrusters, as well as revamped syntactic foam -- which provides buoyancy and structural rigidity when compressed at depth.
When Phase Two begins by 2015, Alvin will be completely retrofitted to withstand the immense pressure 6,500 meters of water exerts on a hull, opening up 98 per cent of the seafloor for exploration. (Only China's 7000m rated Jaolong will be able to dive deeper. This second round of improvements will also see Alvin's antiquated lead-acid batteries swapped out for lighter, higher-capacity stacks that should extend its maximum dive time from 10 to 12 hours.
You can check in on Alvin's ongoing evolution via the WHOI live workshop webcam.
Image: Kurt Uetz / Woods Hole Oceanographic Institution