I was astonished to read that a vintage brass 19th-century Howell torpedo has been recovered from the seabed off Coronado in California. What's more, its discovery was both serendipitous and probably unique. Stars & Stripes reports:
The so-called Howell torpedo was discovered by bottlenose dolphins being trained by the Navy to find undersea objects, including mines, that not even billion-dollar technology can detect.
. . .
At the Point Loma facility, 80 dolphins and 40 sea lions are being trained for mine detection, mine clearing and swimmer protection. When the U.S. led an invasion of Iraq in 2003, dolphins were rushed to the Persian Gulf to patrol for enemy divers and mines. Dolphins guard U.S. submarine bases in Georgia and Washington state. This fall, dolphins will deploy for a mine-hunting mission off Croatia.
To train the dolphins, Navy specialists sink objects in various shapes in rocky and sandy undersea areas where visibility is poor. The shapes mimic those of the mines used by U.S. adversaries.
A dolphin is then ordered to dive and search. If it finds something, it is trained to surface and touch the front of the boat with its snout. If it has found nothing, it touches the back of the boat.
When a dolphin named Ten surfaced from a shallow-water dive last month and touched the front of the boat, Navy specialists were nonplused. "It went positive in a place we didn't expect," said Mike Rothe, who heads the marine mammal program.
A week later, a dolphin named Spetz did the same thing in the same area. This time, the dolphin was ordered to take a marker to the object.
Navy divers and then explosive-ordnance technicians examined the object, which was in two pieces, and determined that the years had rendered it inert. On one piece was the stamp "USN No. 24."
The torpedo pieces were lifted to the surface and taken to a Navy base for cleaning and to await shipment to the Naval History and Heritage Command, located at the Washington Navy Yard.
There's more at the link.
The Howell torpedo was one of the first designs that actually worked as intended. You could 'fire it and forget it'; it would run in a straight line (albeit not very far) at the depth you pre-set, and explode on striking its target. Only one was previously known to exist, at the Naval Undersea Museum in Washington, DC. Here's a picture of that unit from the Museum's Web page about it.
There are more pictures at Wikipedia's article.
Kudos to the dolphins and their trainers. I hope they got extra fish for that - and not the 'tin fish' variety, either!