Two years ago at Gadgetoff in New York City, I saw John Abele speak about his family's search for the USS Grunion [video], a submarine his father captained that was lost during WWII. The Navy listed it as "missing, presumed lost" and never discovered what had happened to it.
The three Abele brothers pooled their resources and funded an expedition to the Aleutian Islands in the Pacific to search for the Grunion near the area it was thought to have last had radio contact (they have chronicled the entire process on their blog). They not only wanted to locate it and verify that it had sunk, but they wanted to discover what had happened -- a weapons malfunction? An enemy torpedo?
First, they had to locate it. They knew approximately where it was last located; by using a sonar towfish towed by an Alaskan crab fishing boat, they obtained a gritty sonar image and rough GPS position of an object they thought was likely to be the Grunion. A year later -- due to weather conditions in that part of the Pacific, they only had a limited window each year in August to do this work -- they decided to go in closer. To do this, they used a MAX Rover ROV from Deep Sea Systems. The MAX Rover, weighing in at nearly a ton, is a boxy underwater vehicle with two manipulator arms, video cameras, and an imaging sonar. Piloting the ROV over its tether to a spot more than a mile under water, they were able to locate the wreck and get in close for imagery of the hull and what damage they could find.
This image from the Grunion blog shows what a submarine periscope looks like after more than half a century at the bottom of the ocean. All of the photographs -- including some incredible imagery from the ROV camera -- is here.
After the August 2007 ROV expedition, based on the shape of the wreck (things like the prop guards that are characteristic of certain classes of submarines) the Abeles were confident they had found what they were looking for and began comparing the imagery to historic accounts on what might have happened during its last enemy engagement that could have caused it to sink. Though full forensic analysis is still ongoing, they have a lot more information to work with, as the image below shows.
From the blog, an artist's rendition of the Grunion wreck, based on the imagery brought back from the ROV expedition.
This week, the Navy officially confirmed that the submarine they discovered was in fact the USS Grunion. As this and other articles indicate, some of the families refused to move on during the war -- not accepting payouts from the Navy or widows deciding not to remarry -- because of the hope that the crewmen could still be alive, since the Navy had never confirmed the loss of the sub. More than six decades later, these families finally have closure.
Nothing that this ROV did is particularly new or notable in robotics, but I think it's a really wonderful application of technology normally reserved for defense or scientific use. Without the ROV, finding this needle in a haystack would have been next to impossible.